12V AUXILIARY BATTERY BOX
The 12V Auxiliary Battery Box is a universal box that can be customized to suit the individual’s needs.
Additional output ports can be added as required.
This product is not a dual battery system and additional systems might be required.
Features:
Fused Outputs
Simple Installation
Built-in Battery Volt meter
Compatible with most vehicles
2 x USB charge ports standard
2 x DC Sockets standard (1 x Cigar , 1 x Hella)
2 x 50A Grey coupler plugs standard
4 x Spare pre-wired output ports
NL5 Intelligent Charger port (charger available separately)
Suitable for most automotive batteries
Dimensions – Black box (L x W x H) : 495mm x 255mm x 300mm
The 12V Auxiliary Battery Box is a universal box that can be customized to suit the individual’s needs.
Additional output ports can be added as required.
This product is not a dual battery system and additional systems might be required.
Features:
Fused Outputs
Simple Installation
Built-in Battery Volt meter
Compatible with most vehicles
2 x USB charge ports standard
2 x DC Sockets standard (1 x Cigar , 1 x Hella)
2 x 50A Grey coupler plugs standard
4 x Spare pre-wired output ports
NL5 Intelligent Charger port (charger available separately)
Suitable for most automotive batteries
Dimensions – Black box (L x W x H) : 495mm x 255mm x 300mm
WARN® ZEON® 10
10,000 lbs. of cutting-edge pulling muscle
Choose your way to conquer the terrain. The ZEON 10 is tough enough to tackle anything you will, with a look that is advanced, capable and strong. Muck-busting sealing keeps out everything but the good times. Add a hyper-durable cast-aluminum housing, satin-black finish, and 10,000 lbs. single-line pulling capacity and, well, you've got a workhorse unit you can trust for years to come.
10,000 lbs. of cutting-edge pulling muscle
Choose your way to conquer the terrain. The ZEON 10 is tough enough to tackle anything you will, with a look that is advanced, capable and strong. Muck-busting sealing keeps out everything but the good times. Add a hyper-durable cast-aluminum housing, satin-black finish, and 10,000 lbs. single-line pulling capacity and, well, you've got a workhorse unit you can trust for years to come.
- 10,000 lb. (4536 kg) single-line pulling capacity.
- Includes 80' of 3/8" galvanized steel wire rope
- Convertible control pack can be attached to the winch or remotely mounted, allowing for various winch mounting options and looks. (Relocation kit required and sold separately*)
- Updated planetary gear train and series-wound motor deliver fast, quiet, and reliable pulling power
- Satin-black powder-coated finish with stainless steel fasteners and clutch lever looks great and inhibits corrosion. Improved winch sealing to keep the elements out.
- Large diameter winch drum reduces rope wear, is light weight, and has an integrated rope anchor for easy rope installation.
The Warn guide to winching
How it works,What’s that noise?
Modern cars are a lot quieter than their older stable-mates, but as time goes by the general noise-level tend to rise, because most components tend to get noisier as they wear.
Noise is caused by a vibration that usually gets worse over time and is often a signal that some component needs attention. When an unwanted noise shows up, the cause should be investigated.
Any vibration that changes with engine speed is obviously related to some engine component. The alternator or water pump often rotate at speeds quite different from the engine’s rotation, but the speeds of these items still rise and fall together. If the vibration is gone when the car is stationary, but the engine is running, then the engine is blameless. This blog will concentrate on vibration and noise from the engine
What is normal?
The smoothness of most modern engines is due to multiple balance masses on the crankshaft and a vibration damper on the end of the crankshaft. Additional balance shafts in the cylinder block and sophisticated engine/gearbox mountings also play a role. The engines in some of the cheapest cars do not have all of these features, and this tends to increase their vibration levels. One should be familiar with a particular engine before making a judgment about what is normal.
Pinking
This noise is no longer as familiar as it used to be. It sounds like a tin can full of nails being shaken under the bonnet, and usually occurs every time the throttle is wide open. This could damage pistons or valves if it is allowed to occur all the time.
The temporary cure is to avoid large throttle openings so that pinking cannot occur. The permanent cure is to find out why the engine is pinking. Possible reasons include ignition timing that is too far advanced, running on fuel having too low an octane value, an overheating engine, using spark plugs having the wrong heat value, or a fuel mixture that is set too lean.
Some ECU-equipped engines will have a knock sensor that is supposed to retard ignition timing, and when this fails pinking may occur. Very often it is caused by a large carbon build-up inside the engine, and on modern engines it may also be due to a faulty EGR (exhaust gas recycling) valve.
Tappets
Engine tappets make a clicking sound that increases with engine revs when they’re set too loose, when some of the valve train components are worn or when the oil pressure is low. Loose tappets may not cause immediate damage, but should be reset soon. Some of the tappets may be too tight, even if the others are loose, and will be quiet, and this may result in burnt valve-seats.
These days most engines will be fitted with hydraulic tappets that tend to be noisy when the engine is cold, but should quieten down as the engine warms up. If the noise doesn’t go away, the tappets may be worn or there may be a dirt particle clogging one of the tappets. Dirty engine oil often causes valve noise, and may even be responsible for so much wear so that when it is replaced with fresh oil the noise will remain.
Piston pins
Noisy piston pins are quite rare, due to improved machining techniques. They tend to make a light clicking noise during idling when they have too much clearance. This usually does not mean that an immediate fix is needed, because they will remain noisy for a long time before causing any damage.
Crankshaft bearings
A deep rapping sound from the engine that starts or gets worse as the engine warms up is usually due to a big-end or main bearing that has too much clearance. This can be due to excessive wear brought on by a high mileage, low oil pressure, or faulty assembly. The knock from a big-end bearing is usually lighter than a main bearing knock, and the sound is more prominent when the engine is neither pulling nor slowing down.
Timing chain
A rattling noise when the engine is idling may be due to a worn timing chain. This is almost normal on some of the older cars, so that a mechanic’s advice is needed to decide whether it’s normal for the particular model, or whether you should have the chain replaced. If the engine has a timing belt instead of a chain the noise will sound more like a slap than a rattle, but a new belt should be quiet.
Accessories
Most engine accessories cause a noise rather than a vibration. Fan belts or serpentine belts respond to misalignment by making a noise. Air cleaners and their mounting brackets often vibrate noisily. Alternators and water pumps often get noisy long before they fail, and it’s sometimes difficult to decide where the noise is coming from. Many mechanics use a steel or wooden probe to isolate the source, but an automotive stethoscope is even more effective. A power steering pump drive pulley screech is a familiar sound. It occurs when the drive belt does not have enough tension, and is brought on as soon as the steering wheel gets near the full-lock position.
Noise is caused by a vibration that usually gets worse over time and is often a signal that some component needs attention. When an unwanted noise shows up, the cause should be investigated.
Any vibration that changes with engine speed is obviously related to some engine component. The alternator or water pump often rotate at speeds quite different from the engine’s rotation, but the speeds of these items still rise and fall together. If the vibration is gone when the car is stationary, but the engine is running, then the engine is blameless. This blog will concentrate on vibration and noise from the engine
What is normal?
The smoothness of most modern engines is due to multiple balance masses on the crankshaft and a vibration damper on the end of the crankshaft. Additional balance shafts in the cylinder block and sophisticated engine/gearbox mountings also play a role. The engines in some of the cheapest cars do not have all of these features, and this tends to increase their vibration levels. One should be familiar with a particular engine before making a judgment about what is normal.
Pinking
This noise is no longer as familiar as it used to be. It sounds like a tin can full of nails being shaken under the bonnet, and usually occurs every time the throttle is wide open. This could damage pistons or valves if it is allowed to occur all the time.
The temporary cure is to avoid large throttle openings so that pinking cannot occur. The permanent cure is to find out why the engine is pinking. Possible reasons include ignition timing that is too far advanced, running on fuel having too low an octane value, an overheating engine, using spark plugs having the wrong heat value, or a fuel mixture that is set too lean.
Some ECU-equipped engines will have a knock sensor that is supposed to retard ignition timing, and when this fails pinking may occur. Very often it is caused by a large carbon build-up inside the engine, and on modern engines it may also be due to a faulty EGR (exhaust gas recycling) valve.
Tappets
Engine tappets make a clicking sound that increases with engine revs when they’re set too loose, when some of the valve train components are worn or when the oil pressure is low. Loose tappets may not cause immediate damage, but should be reset soon. Some of the tappets may be too tight, even if the others are loose, and will be quiet, and this may result in burnt valve-seats.
These days most engines will be fitted with hydraulic tappets that tend to be noisy when the engine is cold, but should quieten down as the engine warms up. If the noise doesn’t go away, the tappets may be worn or there may be a dirt particle clogging one of the tappets. Dirty engine oil often causes valve noise, and may even be responsible for so much wear so that when it is replaced with fresh oil the noise will remain.
Piston pins
Noisy piston pins are quite rare, due to improved machining techniques. They tend to make a light clicking noise during idling when they have too much clearance. This usually does not mean that an immediate fix is needed, because they will remain noisy for a long time before causing any damage.
Crankshaft bearings
A deep rapping sound from the engine that starts or gets worse as the engine warms up is usually due to a big-end or main bearing that has too much clearance. This can be due to excessive wear brought on by a high mileage, low oil pressure, or faulty assembly. The knock from a big-end bearing is usually lighter than a main bearing knock, and the sound is more prominent when the engine is neither pulling nor slowing down.
Timing chain
A rattling noise when the engine is idling may be due to a worn timing chain. This is almost normal on some of the older cars, so that a mechanic’s advice is needed to decide whether it’s normal for the particular model, or whether you should have the chain replaced. If the engine has a timing belt instead of a chain the noise will sound more like a slap than a rattle, but a new belt should be quiet.
Accessories
Most engine accessories cause a noise rather than a vibration. Fan belts or serpentine belts respond to misalignment by making a noise. Air cleaners and their mounting brackets often vibrate noisily. Alternators and water pumps often get noisy long before they fail, and it’s sometimes difficult to decide where the noise is coming from. Many mechanics use a steel or wooden probe to isolate the source, but an automotive stethoscope is even more effective. A power steering pump drive pulley screech is a familiar sound. It occurs when the drive belt does not have enough tension, and is brought on as soon as the steering wheel gets near the full-lock position.
EFS Africa - World class 4x4 suspension
ABOUT EFS: Enhanced 4WD Suspensions Africa is a subsidiary of EFS Australia since late 2009. The Head Office is based in Jet Park in Johannesburg, backed by a distribution network throughout Southern Africa.
EFS suspensions is a quality driven product range which is designed and tested in Australia by Carol Springs. The complete suspension kits offer superior on-road handling characteristics and greater off-road ability.
EFS has designed and developed a high quality suspension system to combat the harsh African terrain and road conditions. The dedicated research and development team has excelled in the fine tuning of shock absorbers, coil and leaf springs and components, and is constantly reviewing the performance of the systems in order to stay in touch with changing operational conditions and technological improvements.
The EFS Engineers have spent countless hours at the EFS Shock Dynamometer Facility, where they have fine tuned the internal shock absorber valving modules to best suit different makes and models of vehicles. The end result is that the customer can enjoy “On road performance and Off road Excellence”
The approach of EFS Africa team is that of personal contact with all customers, superior product support and active participation in the local off-road lifestyle. The team participates in a wide variety of industry related activities – we “live” the product.
The EFS product range is backed by a 3 year/100 000 km warranty.
EFS suspensions is a quality driven product range which is designed and tested in Australia by Carol Springs. The complete suspension kits offer superior on-road handling characteristics and greater off-road ability.
EFS has designed and developed a high quality suspension system to combat the harsh African terrain and road conditions. The dedicated research and development team has excelled in the fine tuning of shock absorbers, coil and leaf springs and components, and is constantly reviewing the performance of the systems in order to stay in touch with changing operational conditions and technological improvements.
The EFS Engineers have spent countless hours at the EFS Shock Dynamometer Facility, where they have fine tuned the internal shock absorber valving modules to best suit different makes and models of vehicles. The end result is that the customer can enjoy “On road performance and Off road Excellence”
The approach of EFS Africa team is that of personal contact with all customers, superior product support and active participation in the local off-road lifestyle. The team participates in a wide variety of industry related activities – we “live” the product.
The EFS product range is backed by a 3 year/100 000 km warranty.
Conversion: Suspension TJM XGS
TJM XGS 4WD SUSPENSION
For over 30 years TJM have built upon their extensive expertise in the design, testing, manufacture and installation of specialist 4WD suspension for the enthusiast off-roader and many tradesman applications. This period of continuous development has culminated in today’s TJM XGS 4WD Suspension range.
YOU’LL NOTICE THE DIFFERENCE
TJM XGS 4WD Suspension will transform your vehicle to handle the rigours of off-road travel like corrugated roads . TJM XGS Gold Edition 4WD Suspension gives you an improved ride, handling and wheel travel, while carrying increased loads.
Whether you install a set of shock absorbers, a pair of springs or a full TJM XGS 4WD Suspension Kit, you’ll notice an immediate improvement in your vehicles ride, handling, load carrying capabilities and towing ability. We believe it’s the best ride ever that’s why we offer an industry leading Three Year / 50,000Km Warranty.
WHY SUSPENSION IS SO IMPORTANT
A vehicles’ suspension is one of the hardest working components on todays’ 4WDs. With more people experiencing this great country of ours and fitting load bearing accessories like bull bars, roof racks, fuel tanks and the like; suspension is often the most important component to be overlooked. How about starting with springs? With the ability to improve your ride or increase your load carrying characteristics, TJM have constant and variable rate Coil Spring and Leaf Spring designs that are tuned and matched to the range of TJM XGS Gold Edition Shock absorbers. In fact, good shock absorbers play an integral part in keeping your vehicle on all fours when braking, cornering and during wheel articulation. Shock absorbers may also increase your tyre life.
TJM are proud to provide you with suspension that’s a pleasure to use, whether on or off road. The XGS range is the result of the time and resources of a dedicated team and their idea of the ‘best ride ever’ that will continue to deliver the ride you expect.
For over 30 years TJM have built upon their extensive expertise in the design, testing, manufacture and installation of specialist 4WD suspension for the enthusiast off-roader and many tradesman applications. This period of continuous development has culminated in today’s TJM XGS 4WD Suspension range.
YOU’LL NOTICE THE DIFFERENCE
TJM XGS 4WD Suspension will transform your vehicle to handle the rigours of off-road travel like corrugated roads . TJM XGS Gold Edition 4WD Suspension gives you an improved ride, handling and wheel travel, while carrying increased loads.
Whether you install a set of shock absorbers, a pair of springs or a full TJM XGS 4WD Suspension Kit, you’ll notice an immediate improvement in your vehicles ride, handling, load carrying capabilities and towing ability. We believe it’s the best ride ever that’s why we offer an industry leading Three Year / 50,000Km Warranty.
WHY SUSPENSION IS SO IMPORTANT
A vehicles’ suspension is one of the hardest working components on todays’ 4WDs. With more people experiencing this great country of ours and fitting load bearing accessories like bull bars, roof racks, fuel tanks and the like; suspension is often the most important component to be overlooked. How about starting with springs? With the ability to improve your ride or increase your load carrying characteristics, TJM have constant and variable rate Coil Spring and Leaf Spring designs that are tuned and matched to the range of TJM XGS Gold Edition Shock absorbers. In fact, good shock absorbers play an integral part in keeping your vehicle on all fours when braking, cornering and during wheel articulation. Shock absorbers may also increase your tyre life.
TJM are proud to provide you with suspension that’s a pleasure to use, whether on or off road. The XGS range is the result of the time and resources of a dedicated team and their idea of the ‘best ride ever’ that will continue to deliver the ride you expect.
How to Drive on Rocks
More than any other type of four wheel driving, picking and climbing through rocks requires real feel for the vehicle. For some people ‘Rock Crawling’ is a competitive sport and an opportunity to customize a vehicle specifically to challenge the toughest of terrain.
For most people driving over large sections of good size rocks will simply be about with getting from point A to B and many people would prefer to take a longer route than subject their bodies and vehicles to the rigours of bundu-bashing. With a little patience driving over rock doesn’t have to be an experience that leaves your passengers regretting the trip or your car battered and bruised.
Thrashing It and Control
This is precisely the time a little self-control and planning needs to be employed. The take a run-up and thrash-it-over-the-hill approach just doesn’t cut it on the rocks. Most likely the car will end up stuck, with at least one flat tyre, probably some panel damage and possibly a fair bit of damage to the undercarriage.
Select low range 4x4, first or second gear, and choose a driving line. Think constantly about where each individual tyre will be placed and where the highest ground is so as to keep the car from bottoming out. Avoid having the car wedged atop a mound and see-sawing unable to move on. Likewise deep gullies are great places to lodge your front and rear bumpers and leave all four wheels swinging in the breeze.
Avoid dropping both front wheels over ledges together and approach them at an angle allowing each wheel to enter and depart the obstacle individually.
Focus and Rhythm
Don’t focus your eyes on the two metres at the front of your car. Because of your slow speed you have plenty of time to scan the route and modify it as you go. With practise you will always have a solid path picked out and the actual driving is just a matter of going through the motions.
Torque and rhythm are the keys and by selecting a low enough gear small throttle adjustments are all that is required to maintain smooth movement. The brake will really only be used to wash off momentum after surging over a larger obstacle while the low gearing nearly makes the clutch redundant. You certainly don’t want to be coasting over rocks with the clutch depressed letting the car drive itself. You need to propel the vehicle.
The aim is to maintain a forward rocking motion, ‘stepping’ from one rock to another and letting each individual wheel find traction. This is the 'feel' component. This combination of gearing, throttle control and wheel placement results in what can be a quite boring and hypnotic drive – albeit one that can involve quite a bit of rolling around from the occupants. It is about constant weight transfer and changes in traction while allowing the car to do its job.
Hills
Even the steepest of hills can be ascended and descended safely providing the car is not allowed to achieve such extreme angles as to roll. Because each wheel is involved in the climbing process it virtually wedges itself between each rock providing a sort of anchor for the next wheel to take over. Water, mud and loose rocks all change the dynamics of this situation and care and good judgement should be used before tackling any large slope.
Drive vertically up and down steep hills. Much like driving in sand dunes the constant weight shifting involved can present problems if the vehicle is driven across the face of hills.
Available ground clearance is vital when driving over rocks and if you are attempting to climb boulders larger than the gap under your car you are probably going to end up in trouble.
Tyre pressure for sand has been written about here, however, it also plays an important role in climbing rocks. We are trying to achieve a soft, flexible reaction from the tyres and by releasing some air we can get them to mould and grip the rocks. Reduced pressure also has the effect of making the tyres act like shock absorbers rather than a fully inflated tyre that bounces off the rocks. The image above illustrates how a fully inflated tyre bounces over rocks compared to a tyre deflated by about 25%.
Care should be taken not to pinch the vulnerable sidewalls between rocks and to not slam wheels into rocks and damage rims.
Driving through rocks is not the most comfortable way to travel but sometimes it is the only route to a destination. The key is care and control - bashing your way through eventually leaves bodies sore and 4WD's broken.
For most people driving over large sections of good size rocks will simply be about with getting from point A to B and many people would prefer to take a longer route than subject their bodies and vehicles to the rigours of bundu-bashing. With a little patience driving over rock doesn’t have to be an experience that leaves your passengers regretting the trip or your car battered and bruised.
Thrashing It and Control
This is precisely the time a little self-control and planning needs to be employed. The take a run-up and thrash-it-over-the-hill approach just doesn’t cut it on the rocks. Most likely the car will end up stuck, with at least one flat tyre, probably some panel damage and possibly a fair bit of damage to the undercarriage.
Select low range 4x4, first or second gear, and choose a driving line. Think constantly about where each individual tyre will be placed and where the highest ground is so as to keep the car from bottoming out. Avoid having the car wedged atop a mound and see-sawing unable to move on. Likewise deep gullies are great places to lodge your front and rear bumpers and leave all four wheels swinging in the breeze.
Avoid dropping both front wheels over ledges together and approach them at an angle allowing each wheel to enter and depart the obstacle individually.
Focus and Rhythm
Don’t focus your eyes on the two metres at the front of your car. Because of your slow speed you have plenty of time to scan the route and modify it as you go. With practise you will always have a solid path picked out and the actual driving is just a matter of going through the motions.
Torque and rhythm are the keys and by selecting a low enough gear small throttle adjustments are all that is required to maintain smooth movement. The brake will really only be used to wash off momentum after surging over a larger obstacle while the low gearing nearly makes the clutch redundant. You certainly don’t want to be coasting over rocks with the clutch depressed letting the car drive itself. You need to propel the vehicle.
The aim is to maintain a forward rocking motion, ‘stepping’ from one rock to another and letting each individual wheel find traction. This is the 'feel' component. This combination of gearing, throttle control and wheel placement results in what can be a quite boring and hypnotic drive – albeit one that can involve quite a bit of rolling around from the occupants. It is about constant weight transfer and changes in traction while allowing the car to do its job.
Hills
Even the steepest of hills can be ascended and descended safely providing the car is not allowed to achieve such extreme angles as to roll. Because each wheel is involved in the climbing process it virtually wedges itself between each rock providing a sort of anchor for the next wheel to take over. Water, mud and loose rocks all change the dynamics of this situation and care and good judgement should be used before tackling any large slope.
Drive vertically up and down steep hills. Much like driving in sand dunes the constant weight shifting involved can present problems if the vehicle is driven across the face of hills.
Available ground clearance is vital when driving over rocks and if you are attempting to climb boulders larger than the gap under your car you are probably going to end up in trouble.
Tyre pressure for sand has been written about here, however, it also plays an important role in climbing rocks. We are trying to achieve a soft, flexible reaction from the tyres and by releasing some air we can get them to mould and grip the rocks. Reduced pressure also has the effect of making the tyres act like shock absorbers rather than a fully inflated tyre that bounces off the rocks. The image above illustrates how a fully inflated tyre bounces over rocks compared to a tyre deflated by about 25%.
Care should be taken not to pinch the vulnerable sidewalls between rocks and to not slam wheels into rocks and damage rims.
Driving through rocks is not the most comfortable way to travel but sometimes it is the only route to a destination. The key is care and control - bashing your way through eventually leaves bodies sore and 4WD's broken.
10 Golden Rules when selecting a 4×4
Rule 1. Not all 4x4s are created equal.
Few 4x4s are really good at everything. Some are good for almost nothing relating to off-road. Every 4×4 is a compromise in some way: some that are good on road should never leave it, and others good off it, are a test of endurance on it. As a buyer, you will need to compromise just as the designers have done. Decide where your compromises are going to lie as you go about choosing a 4×4.
Rule 2. Know more than the showroom salesperson about 4x4s or you may be taken for an unsatisfactory ride.
It has taken years, but salespersons are at last beginning to learn more about the 4x4s they are selling. But this doesn’t prevent them selling you what you do not want. They will always make an effort to tell you what you want to hear, and rarely what you need to hear. The only way to outwit them is to do some homework and to have made a few fundamental decisions before meeting the sale force. The danger lies in that most of us are easily baffled by bull delivered by an experienced salesperson.
Rule 3. Beware of the phrase, “I don’t want to do anything serious”.
If you hear this in your mind, it’s a danger sign because what does serious really mean? It is vital to be clear on what you expect from your vehicle choice and to know if your choice can do it.
Rule 4. Beware of the myth that a 4×2 with a diff-lock can do almost as much off-road as a 4×4. It’s not even close!
This is because only when an axle on a surface where weight or grip is removed from one of the driven wheels will traction be assisted with an axle diff lock. Everywhere else it makes little or no difference to a vehicle’s ability off-road. A diff-lock does help in some situations, but to compare it to two additional driven wheels, on a completely separate axle, is ludicrous.
Rule 5. Beware of the other myth that says a 4×4 without low range can do almost as much as a 4×4 with low range.
Again their performance off-road is not even close! Low range extends a vehicle’s versatility beyond what is imaginable, as long as the vehicle is also equipped with reasonable clearance, so that the low gearing can be taken full advantage of.
Rule 6. Decent under chassis clearance is essential if any off-road driving is contemplated.
This seems obvious, but to some it appears not to be. The measurement of minimum clearance given in the sales brochure tells only half the story, so beware of comparing figures. It might seem simplistic, but one of the best ways to judge clearance is to stand back and look at the vehicle. If it looks low then it is!
Rule 7. Full-time four-wheel drive provides any vehicle a significant safety advantage.
The added grip, neutral steering and sheer pleasure of driving a full-time four-wheel drive transmission is often offset by the fact that most 4x4s have a high centre of gravity and therefore fall over easier. All in all, 4x4s are not necessarily safer than similar sized and equipped saloons. So if you are going 4×4 for safety reasons, the low-slung models are going to have a safety advantage.
Rule 8. Don’t be dazzled by the words, ‘diff-lock’ and ‘traction-control’.
Diff-locks and traction-control are not magical devices that prevent vehicles getting stuck, although they do, in many cases, go a long way toward it. It is so easy to be confused here and it is important to understand that one vehicle with one of these systems may behave utterly differently to another. Over simplified vehicle buyer’s guides that give a yes/no answer to the question of diff-locks and traction controls can be misleading because some traction-controls work brilliantly while others hardly work at all and diff locks can be located in varying locations in the transmissions, and as a result, have widely varying effects.
Rule 9. Bling and off-road should never be used in the same sentence.
Bling usually means big wheel rims, often shiny and always a hindrance off road. It isn’t the shine that is the problem, but a low profile tyre, when its pressure is reduced for flotation and traction off the road, it does not lengthen its footprint as much as a higher profile tyre does. Overly large rims are a sure way to take the shine off any attempt at going off road.
The second problem comes with outback travel because low profile tyres are far more prone to damage by rocks and stones, and when they are damaged, spare 17, 18 and 19-inch tyres can rarely, if ever be found in remote towns and villages. 16-inch rims seem to be the ideal size. And if a vehicle has a narrow, space-saving spare, it’s going to need to be changed for a real one before heading out.
Rule 10. Reliability means different things to different people.
Some vehicles have particularly good reputations for reliability and others less so. But reliability can mean two things: If you are capable of making repairs, serviceability is as important as reliability. If you are incapable of making more than basic repairs, reliability is probably the most important factor in choosing a 4×4 for outback travel. Establishing a vehicle’s reliability can only be done through clubs, friends and the Internet. For obvious reasons it’s pointless asking the salesperson.
Few 4x4s are really good at everything. Some are good for almost nothing relating to off-road. Every 4×4 is a compromise in some way: some that are good on road should never leave it, and others good off it, are a test of endurance on it. As a buyer, you will need to compromise just as the designers have done. Decide where your compromises are going to lie as you go about choosing a 4×4.
Rule 2. Know more than the showroom salesperson about 4x4s or you may be taken for an unsatisfactory ride.
It has taken years, but salespersons are at last beginning to learn more about the 4x4s they are selling. But this doesn’t prevent them selling you what you do not want. They will always make an effort to tell you what you want to hear, and rarely what you need to hear. The only way to outwit them is to do some homework and to have made a few fundamental decisions before meeting the sale force. The danger lies in that most of us are easily baffled by bull delivered by an experienced salesperson.
Rule 3. Beware of the phrase, “I don’t want to do anything serious”.
If you hear this in your mind, it’s a danger sign because what does serious really mean? It is vital to be clear on what you expect from your vehicle choice and to know if your choice can do it.
Rule 4. Beware of the myth that a 4×2 with a diff-lock can do almost as much off-road as a 4×4. It’s not even close!
This is because only when an axle on a surface where weight or grip is removed from one of the driven wheels will traction be assisted with an axle diff lock. Everywhere else it makes little or no difference to a vehicle’s ability off-road. A diff-lock does help in some situations, but to compare it to two additional driven wheels, on a completely separate axle, is ludicrous.
Rule 5. Beware of the other myth that says a 4×4 without low range can do almost as much as a 4×4 with low range.
Again their performance off-road is not even close! Low range extends a vehicle’s versatility beyond what is imaginable, as long as the vehicle is also equipped with reasonable clearance, so that the low gearing can be taken full advantage of.
Rule 6. Decent under chassis clearance is essential if any off-road driving is contemplated.
This seems obvious, but to some it appears not to be. The measurement of minimum clearance given in the sales brochure tells only half the story, so beware of comparing figures. It might seem simplistic, but one of the best ways to judge clearance is to stand back and look at the vehicle. If it looks low then it is!
Rule 7. Full-time four-wheel drive provides any vehicle a significant safety advantage.
The added grip, neutral steering and sheer pleasure of driving a full-time four-wheel drive transmission is often offset by the fact that most 4x4s have a high centre of gravity and therefore fall over easier. All in all, 4x4s are not necessarily safer than similar sized and equipped saloons. So if you are going 4×4 for safety reasons, the low-slung models are going to have a safety advantage.
Rule 8. Don’t be dazzled by the words, ‘diff-lock’ and ‘traction-control’.
Diff-locks and traction-control are not magical devices that prevent vehicles getting stuck, although they do, in many cases, go a long way toward it. It is so easy to be confused here and it is important to understand that one vehicle with one of these systems may behave utterly differently to another. Over simplified vehicle buyer’s guides that give a yes/no answer to the question of diff-locks and traction controls can be misleading because some traction-controls work brilliantly while others hardly work at all and diff locks can be located in varying locations in the transmissions, and as a result, have widely varying effects.
Rule 9. Bling and off-road should never be used in the same sentence.
Bling usually means big wheel rims, often shiny and always a hindrance off road. It isn’t the shine that is the problem, but a low profile tyre, when its pressure is reduced for flotation and traction off the road, it does not lengthen its footprint as much as a higher profile tyre does. Overly large rims are a sure way to take the shine off any attempt at going off road.
The second problem comes with outback travel because low profile tyres are far more prone to damage by rocks and stones, and when they are damaged, spare 17, 18 and 19-inch tyres can rarely, if ever be found in remote towns and villages. 16-inch rims seem to be the ideal size. And if a vehicle has a narrow, space-saving spare, it’s going to need to be changed for a real one before heading out.
Rule 10. Reliability means different things to different people.
Some vehicles have particularly good reputations for reliability and others less so. But reliability can mean two things: If you are capable of making repairs, serviceability is as important as reliability. If you are incapable of making more than basic repairs, reliability is probably the most important factor in choosing a 4×4 for outback travel. Establishing a vehicle’s reliability can only be done through clubs, friends and the Internet. For obvious reasons it’s pointless asking the salesperson.
Vehicle Recovery
Understanding the basics:
A lot of people make the mistake of just pulling out a winch line, wrapping it around a tree, and powering the winch in. No, no, no. That may get you unstuck, but it’s risky and can be dangerous. There are proper methods and proper steps that should be followed that can reduce the risks inherent to off road vehicle recovery. I’ll take you through the process step by step in the following article.
Before proceeding with any recovery steps or tactics, the basics need to be discussed. The most basic thing to understand is that any recovery process creates large loads through the equipment that is in the system (‘the system’ refers to any component in use during the recovery, including the vehicles and anchor points). An important thing to understand is the WLL, or working load limit, of the equipment. By understanding the loads that the system can possibly experience, and exceeding those limits with the strength of the components in the system, you increase your safety factor. A safety factor is the breaking strength of the weakest component of the system, divided by the force being exerted on that component. A high safety factor is desired to ensure that no breakage can occur.
All good recovery equipment has WLLs labelled on them, or at least on their packaging. Some components are labelled in tons, some in kilograms, and some in pounds. Make sure you know the conversions between the units and understand your weakest link. You often want to design your system so the weakest link is the pulling mechanism (you or a motor). If your pulling component isn’t the weakest link, it is actually possible to fail a component in the system. The weakest component in the system is known as the ‘fuse’.
It’s important to understand how the forces transfer, not only through the recovery equipment, but also through the vehicle. Make sure the recovery points on the vehicle can withstand the forces involved in a recovery situation, and that they can transmit the forces to the frame. Even then, make sure you understand where the stuck-forces are coming from. If you have a vertical rock face in front of one of your tires, a recovery force could end up bending your tie rod before moving the vehicle.
It’s also important to understand the three main categories of recovery.
§ Static – not putting impulse loads on the system: winching
§ Dynamic – recovery by momentum: yanked rope, snatch strap
§ Passive – use of traction aids, not inducing horizontal loads on the vehicle
A static recovery loads the recovering system without any stretching component. The recovery force is derived from a positive displacement element, such as a winch, or hand ratchet. Dynamic elements, such as ‘snatch’ straps, should not be used in a static recovery unless it is a last resort.
A dynamic recovery can be useful for a quick recovery, provided you have a second vehicle present. The recovery force is derived from the other vehicle’s momentum. If a dynamic strap is not used in this type of recovery, extreme damage can result.
A passive recovery does not utilize horizontal forces at all to recover the vehicle. The recovery is performed by simply increasing the wheel traction through various methods.
These three methods will be covered in depth on the coming pages.
Lastly… whenever a vehicle gets stuck or needs aid remember the 3 P`s before performing any recovery. Patience, Plan and then Practice. I’ve adapted the 3 P`s into the following four steps:
1 - Assess
2 - Plan
3 - Envision
4 - Perform
A lot of people make the mistake of just pulling out a winch line, wrapping it around a tree, and powering the winch in. No, no, no. That may get you unstuck, but it’s risky and can be dangerous. There are proper methods and proper steps that should be followed that can reduce the risks inherent to off road vehicle recovery. I’ll take you through the process step by step in the following article.
Before proceeding with any recovery steps or tactics, the basics need to be discussed. The most basic thing to understand is that any recovery process creates large loads through the equipment that is in the system (‘the system’ refers to any component in use during the recovery, including the vehicles and anchor points). An important thing to understand is the WLL, or working load limit, of the equipment. By understanding the loads that the system can possibly experience, and exceeding those limits with the strength of the components in the system, you increase your safety factor. A safety factor is the breaking strength of the weakest component of the system, divided by the force being exerted on that component. A high safety factor is desired to ensure that no breakage can occur.
All good recovery equipment has WLLs labelled on them, or at least on their packaging. Some components are labelled in tons, some in kilograms, and some in pounds. Make sure you know the conversions between the units and understand your weakest link. You often want to design your system so the weakest link is the pulling mechanism (you or a motor). If your pulling component isn’t the weakest link, it is actually possible to fail a component in the system. The weakest component in the system is known as the ‘fuse’.
It’s important to understand how the forces transfer, not only through the recovery equipment, but also through the vehicle. Make sure the recovery points on the vehicle can withstand the forces involved in a recovery situation, and that they can transmit the forces to the frame. Even then, make sure you understand where the stuck-forces are coming from. If you have a vertical rock face in front of one of your tires, a recovery force could end up bending your tie rod before moving the vehicle.
It’s also important to understand the three main categories of recovery.
§ Static – not putting impulse loads on the system: winching
§ Dynamic – recovery by momentum: yanked rope, snatch strap
§ Passive – use of traction aids, not inducing horizontal loads on the vehicle
A static recovery loads the recovering system without any stretching component. The recovery force is derived from a positive displacement element, such as a winch, or hand ratchet. Dynamic elements, such as ‘snatch’ straps, should not be used in a static recovery unless it is a last resort.
A dynamic recovery can be useful for a quick recovery, provided you have a second vehicle present. The recovery force is derived from the other vehicle’s momentum. If a dynamic strap is not used in this type of recovery, extreme damage can result.
A passive recovery does not utilize horizontal forces at all to recover the vehicle. The recovery is performed by simply increasing the wheel traction through various methods.
These three methods will be covered in depth on the coming pages.
Lastly… whenever a vehicle gets stuck or needs aid remember the 3 P`s before performing any recovery. Patience, Plan and then Practice. I’ve adapted the 3 P`s into the following four steps:
1 - Assess
2 - Plan
3 - Envision
4 - Perform
4x4 Driving Techniques
Driving a 4x4 off-road is an acquired skill. Think safety at all times. DON'T TAKE RISKS. Practise techniques first before having to use them in earnest. Better still; learn them correctly at a 4x4 off road centre. Advice here is biased towards environmentally friendly codes of conduct. On a serious 4x4 expeditions, vehicle safety may take preference over environmental issues. Your life may depend on it.
Deep Ruts and Ditches:
Be aware of your vehicles ground clearance and location of its lowest points. Allow wheels to follow their own route inside a deep rut and avoid over steering. Grip the wheel lightly but be prepared to take firm control if necessary. Cross ditches at an angle, never direct on. Learn about your vehicle's approach and departure angles beforehand.
Deep Water:
You need to check for submerged objects, underwater potholes and whether the bottom is solid or soft mud. If you can't see bottom then walk where the left tyre will go and return by where the right tyre will go. Sideways currents can affect directional steering. Turn off air con. If the water could reach the cooling fan then it's best to switch off the engine and let it cool. That way an electric fan won't start up in the crossing. Rotating fan blades can bend in the water and damage the radiator. Remember your tyres act as floats, lowering the pressure your vehicle puts on the ground. It's therefore easier for the vehicle to be pushed sideways. You are usually safe up to the hubs and probably up to the door sills. Go slow and steady pushing a bow wave in front. The wave causes a lower water level inside the engine bay. Nurture the wave. Don't stop or accelerate through it. Keep the engine running; if water enters the exhaust it's very difficult to re-start. Check braking after leaving the water. Light pressure on the brake pedal whilst driving a short distance will dry brake shoes and drums. Discs are quicker to dry out. If the water was muddy then brake drums should be removed and cleaned out when possible. If the axles were submerged they may have sucked water in through the breather valve or oil seals when they suddenly cooled. All breather tubes should be raised up above possible water level if you intentionally go deep water crossing. It's a good idea to let hot axles cool before entering cold water. Changing the oil is cheaper than changing the diff and bearings.|
Well fitted snorkels are needed in deep water but all electrics in the engine bay need to be waterproofed also. In emergency, with no snorkel, a radiator blind can be made from tarpaulin. The idea is to stop water passing through the radiator and guide it under the engine. Keep the tarp clear of the wheels and tie it back behind the engine bay securely, avoiding the hot exhaust. If you stall the engine in water you may need to dry all electrics before it will restart, otherwise, cranking the engine in gear will move the vehicle forward or backward.
Hill Climb/Descent
Eyeball it first, walk it if possible. Pick the easiest route avoiding rocks, stumps, holes etc. Check for problematic departure and approach angles. What is at the top of the hill? Tie everything down inside. Select your gear. Go for a steady pace, use as little accelerator as possible but enough to avoid stalling. Stay on the power but if a wheel spins, back off the power a little to get traction again. If you stop on the hill, apply brakes and clutch and immediately select REVERSE. Release the brake and engage the clutch fully. DO NOT BRAKE on the way down. If the wheels lock you'll lose steering and slide sideways and maybe roll over. Reverse down the hill in gear in the straightest line you can WITHOUT BRAKING. The engine will brake safely for you. You can safely back down a hill far too steep to climb without braking.
Use engine braking to slow your descent down a hill not the brakes. If the back end starts to slide around then ACCELERATE slightly to re-gain control. If you brake when driving down a hill and a skid develops EASE OFF THE BRAKE. It goes against instinct but you will gain traction again and therefore be able to steer. Wheels must be turning to be steerable. If the vehicle turns sideways it will probably roll.
Long Grass
This can wrap around the crank pulley, block the radiator, catch fire on the hot exhaust and hide the most amazing obstacles and holes.
Mud
Progress ultimately depends upon the tread on your tyres. The more aggressive the tread, the more likely you are to reach your destination. Even the most aggressive treads cannot cope with wet clay. Turning the steering left and right will often find a bit more grip when progress is about to holt. Steady momentum is again the key to success, frequent gear changing and acceleration are not. You can lower tyre pressures by half, in the same way as driving on sand. Braking should be checked after driving deep mud. Remove mud from your vehicle to prolong chassis life. This is where pressure washers are useful!
Rock Crawling
Generally, large rocks should be hit squarely. The most vulnerable part of a tyre is the sidewall; you need to avoid cuts scratches. Slow steady progress in low gear with your foot off the clutch pedal. With manual gearboxes, brake only if essential. Automatic boxes give less engine braking so you may have to brake gently on the down side of a rock. It's easier to maintain a slow steady momentum than to start off again after a stalled engine. You need to know where all your wheels are and where they will be a few feet further on. Pick a course to avoid getting high-centred. If in doubt, move a rock or pack smaller ones near it.
Sand
Moist or wet sand is not a major problem. If you can see tyre patterns then the sand is firm, but if tyre tracks are narrow vies then the sand is soft. Check that there isn't mostly dry sand just below the surface. If following a vehicle which is breaking through a thin crust, don't follow in their tracks; drive your own crust - less chance of losing critical momentum. The golden rule in soft sand is to MAINTAIN MOMENTUM, AVOID BRAKING and SHARP TURNS. When starting off, do it slowly, even slipping the clutch if necessary -in automatics use 2nd gear. Never change gear or slip the clutch when under load - you will come to a stop quickly. You may need a running start to get the required momentum but you should be in the highest gear that will do the job but we are not talking SPEED here. Reducing tyre pressures by half reduce the requirement for momentum. This is where compressor air pumps are useful! A spinning wheel will dig the vehicle down to the chassis in seconds. If you come to a stop, get out and take a look first, you may need a recovery technique, don't try to power your way out. On sandy steep descents accelerate out of a slide don't brake. Drive straight up or down a dune, don't traverse it and don't drive blind over the top of one. Desert terrain is most easily judged when the sun is low or when the spot lights are placed high on the vehicle. Don't drive through a sand storm - park the vehicle downwind and sit it out. Drive corrugations at the best speed to minimise vibration. If you drive sand regularly, invest in a long handled shovel.
Snow
The secret is to use a low enough gear to keep the engine revving happily, to maintain momentum and avoid changing gear unnecessarily. Remember snow can hide rocks, branches, frozen streams etc. Drive the crown of the track, leave a wide margin for ditches and keep to the high side on a slope.
Turn the steering left and right if climbing and you begin to loose traction. Don't change gear on ice. Drives down a snow slope don’t coast down and then you will maintain control.
Driving through slush in freezing conditions can cause ice to build up around the steering and suspension. In remote areas in winter it makes sense to plan for overnight survival.
The Environment
Care for the land you drive over. Don't use more aggressive tyres than is necessary, lower tyre pressures on fragile land. Don't make tracks, follow the ones that exist. Four driven wheels spread the traction effort needed and are less damaging than two driven wheels. Don't travel in large groups and be aware of the interests of wildlife.
Safety Tips When Taking Your Vehicle Off-Highway
Remember to breathe frequently and sit back and enjoy the ride. All too often, I find people stressing out and clutching the wheel hunched over with the back and shoulder muscles tensed. Relax. That is what you are in the bush for, right? The Zen of the destination is the journey!
Drive as slow as possible, but as fast as necessary. There are times when in soft sand like beaches and washes, speed needs to be moderate and flotation through mud and snow needs to be kept up, hence "as fast as necessary." But usually taking your time on the trail will allow you to pick a smooth path and allow you time to react/act to the varieties of terrain like moving rocks and logs under the tires. If you have a ground clearance deficiency, going slow helps here, in that, if you do hit a rock with the diff or other rock grabber, it will usually stop the vehicle on impact or you will lightly scrape over it. If you were going too fast and hit a rock or other obstacle, it could knock a hole in the oil pan, diff or even knock off the oil filter.
Don't get caught up in the Camel Trophy syndrome. They don't use those rigs as daily drivers. At the end of those events, the keys are handed over to a mechanic and a corporation that has deep pockets to refurbish them. Plus, you could get hurt!
Survey the trail ahead to avoid any "surprises." When in doubt, get out and recon! Make sure the trail goes beyond the obstacle, doesn't become a bottomless quagmire, has no back side to the hill (cliff?) or just plain ends. You can get a good idea where to place your tires and the differentials and have a plan of approach. And follow through to beyond the obstacle.
Don't stop in the middle of the challenge to check it out.Get through it, then walk back and check it out again. See where you actually went. Observe your tire tracks.
Drive directly up and down hills. Traveling diagonally may result in a sideways slide -- worst case, a rollover.
Know your approach and departure angles, the bumper to tire distance. Some trails will require off-camber driving. Just go slow, keeping the tires in the tracks. Don't lose attention and climb up a rock or stump on the up hillside. Vehicles will tend to slide sideways before rolling over. The tires will slip sideways a little. Stop if the slide puts you off the edge of the track. If it is clear downhill and a rollover is imminent, immediately turn the vehicle into the slide and drive it down. If that is not an option, and you are going over, turn the vehicle off and hold on to your seat-bottom and hope the seat belt works properly. You did have it on? There are other scenarios, but this is the least drastic. Use enough momentum to get up and over the hill. Avoid high centering on the crest. Use the engine brake method for the descent.
DO NOT TURN AROUND WHEN ON A HILL. Rollover CAN happen. Practice backing down.
Reduce the tire pressure. This improves traction in all conditions, especially sand. Remember that ground clearance has been compromised. Reinflate before driving on the pavement for any distance.
The easiest way to improve off-highway traction and performance is to "air-down." Depending on the tire you have and type of vehicle, you could go to as much as 1.5bar, even lower, if needed; for soft sand, 1bar.
Be careful to not turn fast and push the tire off the bead.
Read the manufacturer's label. The air pressure difference between the front and rear is due to the tire and auto manufacturers' experimentation for over/under steer and load variances. Carry a mini-compressor to reinflate, or know that an air pump is not far from the trail end.
Cross ditches or logs at an angle so that one wheel at a time goes over the obstacle; the other three help the one wheel to climb over. Dropping the tire into a ditch or crack in a rock is scary! Sometimes the vehicle pitches and one or more tires will catch air. Be very deliberate and careful when approaching this challenge section of any trail. Logs can bounce up and catch the undercarriage, so come off these things slowly and carefully. Turn the vehicle at an angle to facilitate the one tire at a time approach. Be careful not to allow one of the front tires and one of the rear tires to get in the ditch at the same time.
Get to know your vehicle and its performance potential. SQUEEZE the accelerator gently to avoid wheelspin, backing off the pedal when spin does occur, then gaining traction again. A spinning wheel/tire combo, no matter how large, does not give traction. That dirt pile doesn't know the difference from a Mud terrain or a Duel terrain tyre if it is spinning. You still won't get traction. You can't steer, brake or go with a spinning tire! Feel the point where the vehicle is about to stall, squeeze the throttle lightly, then back off the throttle, especially during rock crawling, up hill and snowed-in trails. With automatics you may have to use the left foot on the brake sometimes. Usually when you take your foot off the accelerator, the vehicle seems to "stall," so you put your foot back on the gas pedal and then the vehicle goes too fast. This "herky-jerky" method can be avoided by using finesse with left foot braking and proper throttle modulation. Know your vehicle and the actions and noises of the engine and suspension as you go over the trail.
Avoid lengthy wheelspin; digging into the track only gets you more stuck and ruins the environment. If stuck into the track, use a jack to lift the vehicle. Build up the ground under the tires. Placing brushwood and blankets, etc. under the tires will sometimes help with clearance. On the other hand, once in a while, you will have to let the tires "dig" a little to help forward momentum. If you feel the vehicle starting to lose traction or forward motion, try backing off the throttle then giving a short "blip" on the throttle. Try this a few times in quick succession. If this fails, back up and get another look at the obstacle and try a different approach.
When you think you are getting stuck and the driving tricks don't seem to be helping, immediately back out of the obstacle. Use the winch to get through or go somewhere else. Don't drive off the trail and around the challenge unless there is a legitimate by-pass.
Rocking the vehicle back and forth only serves to dig you in deeper. Sometimes it helps to rock back and forth, then to back out of the obstacle, but usually I don't like to dig deeper. Check under the vehicle to see what is holding it; a rock? a stump? or other grabber thing? Make sure those things are clear before winching or using the recovery strap. I always carry a well-stocked recovery kit!
Keep the use of the brakes to an absolute minimum to keep the wheels from locking up on wet, muddy, loose rock Descend steep slopes in low range and first gear. Rely on engine compression to slow the vehicle. If sliding occurs, drive the vehicle forward to gain traction once again, then back off the throttle. Sometimes when in extreme rocky descents with ledges and shelf steps, the clutch must be pushed in and the brakes used to allow the vehicle to creep forward ever so slowly. This should only be done in those cases. Usually engine control through throttle modulation is best served by engine compression on descents. A locked sliding tire gets no traction.
BEWARE of the LURCH and SURGE! Unless you have lockers engaged on both axles, the lurch and surge will scare the heck out of you until you have experienced it many times. When in gear, no brakes, and open diffs, the vehicle has traction from only one tire on an axle--you know what happens when going uphill and getting traction to only one tire per axle. Well, when going downhill, if the tire that has contact to the transmission gets air or slides, the vehicle will lurch forward because the non-tractive tire has no resistance from the gear box. Usually it is a short surge, and control is gained when the tire contacts good terrain. When that is likely, a light foot pressure on the brake pedal will help to prevent the next lurch. The vehicle will actually "shoot" forward fast for a short distance. If not controlled or anticipated, you could gain momentum and quickly get out of control, especially on long descents.
The same happens when backing down off an ascent as well. When backing down, always be in reverse gear. The same procedure pertains as in the descent. This is especially important when backing down, as the front end becomes light and the steering tires won't give the afforded traction for steering, traction and braking.
Do not oversteer - especially while in ruts or deep tracks. The steering wheel may look centered, but the tires may be at full turn. Murphy's law says-when traction is gained, there will be a big tree or rock at that point. Driving on a trail, many obstacles will be encountered that will move the steering wheel all around. The tire gets lifted up or drops down in a hole and causes the steering wheel to move as if it were turning on a curve. This "wallowing" of the front end and "bump steering" creates the false impression that you must correct the original steering course. Get used to the feeling of the front end articulating over the trail, and hold the steering wheel on-center. Just hold the wheel firmly and "aim" the rig over the trail in those rough sections.
What happens is the steering wheel gets tugged to one side, you correct to the other side, then the next minute the wheel comes right back and you have to correct it again, or actually re-correct it. Now, all you are doing is over-correcting and turning the steering wheel back and forth, wearing out your arms! You do have to steer on the trail and keep the rig centered, but don't oversteer! When in mud or deep ruts, sometimes quickly turning the steering wheel so that with your hands at the "3 and 9" position, you move it halfway round and back almost touching your wrists in a cross over position. This will make the front tires turn back and forth, causing the sidewall edges to help claw their way through.
Make slow, steady progress through deep water to create a "bow wave" and an air pocket in and around the engine compartment and front wheels. This minimizes risk of water drowning the engine. Water does not compress as well as air. Don't let hydrostatic lock ruin your day. Check the brakes after coming out.
Having a plastic sheet or poncho to cover the front of the vehicle, especially around the radiator grill, will help keep most of the water out of the engine bay. Smooth progress through deep water or mud will keep the air pocket stable. A big rock or drop-off will affect the steady progress and "burst your bubble," so be careful! Generally speaking, a deep crossing should be no more than just over the tires. Mud that deep will stick you before the front axle gets half-way. Carry an extra air filter element in case you do drown the engine. Get the vehicle out of the creek, then work on it.
If the engine does swallow some water pull the spark plugs, air filter. Crank the engine over and blow the water out of the cylinders. Check the engine oil before cranking! I have seen the engine completely fill with water. You might have to drain the engine, so do it for the environment and use water jugs or coolers to collect the watered oil.
Deep Ruts and Ditches:
Be aware of your vehicles ground clearance and location of its lowest points. Allow wheels to follow their own route inside a deep rut and avoid over steering. Grip the wheel lightly but be prepared to take firm control if necessary. Cross ditches at an angle, never direct on. Learn about your vehicle's approach and departure angles beforehand.
Deep Water:
You need to check for submerged objects, underwater potholes and whether the bottom is solid or soft mud. If you can't see bottom then walk where the left tyre will go and return by where the right tyre will go. Sideways currents can affect directional steering. Turn off air con. If the water could reach the cooling fan then it's best to switch off the engine and let it cool. That way an electric fan won't start up in the crossing. Rotating fan blades can bend in the water and damage the radiator. Remember your tyres act as floats, lowering the pressure your vehicle puts on the ground. It's therefore easier for the vehicle to be pushed sideways. You are usually safe up to the hubs and probably up to the door sills. Go slow and steady pushing a bow wave in front. The wave causes a lower water level inside the engine bay. Nurture the wave. Don't stop or accelerate through it. Keep the engine running; if water enters the exhaust it's very difficult to re-start. Check braking after leaving the water. Light pressure on the brake pedal whilst driving a short distance will dry brake shoes and drums. Discs are quicker to dry out. If the water was muddy then brake drums should be removed and cleaned out when possible. If the axles were submerged they may have sucked water in through the breather valve or oil seals when they suddenly cooled. All breather tubes should be raised up above possible water level if you intentionally go deep water crossing. It's a good idea to let hot axles cool before entering cold water. Changing the oil is cheaper than changing the diff and bearings.|
Well fitted snorkels are needed in deep water but all electrics in the engine bay need to be waterproofed also. In emergency, with no snorkel, a radiator blind can be made from tarpaulin. The idea is to stop water passing through the radiator and guide it under the engine. Keep the tarp clear of the wheels and tie it back behind the engine bay securely, avoiding the hot exhaust. If you stall the engine in water you may need to dry all electrics before it will restart, otherwise, cranking the engine in gear will move the vehicle forward or backward.
Hill Climb/Descent
Eyeball it first, walk it if possible. Pick the easiest route avoiding rocks, stumps, holes etc. Check for problematic departure and approach angles. What is at the top of the hill? Tie everything down inside. Select your gear. Go for a steady pace, use as little accelerator as possible but enough to avoid stalling. Stay on the power but if a wheel spins, back off the power a little to get traction again. If you stop on the hill, apply brakes and clutch and immediately select REVERSE. Release the brake and engage the clutch fully. DO NOT BRAKE on the way down. If the wheels lock you'll lose steering and slide sideways and maybe roll over. Reverse down the hill in gear in the straightest line you can WITHOUT BRAKING. The engine will brake safely for you. You can safely back down a hill far too steep to climb without braking.
Use engine braking to slow your descent down a hill not the brakes. If the back end starts to slide around then ACCELERATE slightly to re-gain control. If you brake when driving down a hill and a skid develops EASE OFF THE BRAKE. It goes against instinct but you will gain traction again and therefore be able to steer. Wheels must be turning to be steerable. If the vehicle turns sideways it will probably roll.
Long Grass
This can wrap around the crank pulley, block the radiator, catch fire on the hot exhaust and hide the most amazing obstacles and holes.
Mud
Progress ultimately depends upon the tread on your tyres. The more aggressive the tread, the more likely you are to reach your destination. Even the most aggressive treads cannot cope with wet clay. Turning the steering left and right will often find a bit more grip when progress is about to holt. Steady momentum is again the key to success, frequent gear changing and acceleration are not. You can lower tyre pressures by half, in the same way as driving on sand. Braking should be checked after driving deep mud. Remove mud from your vehicle to prolong chassis life. This is where pressure washers are useful!
Rock Crawling
Generally, large rocks should be hit squarely. The most vulnerable part of a tyre is the sidewall; you need to avoid cuts scratches. Slow steady progress in low gear with your foot off the clutch pedal. With manual gearboxes, brake only if essential. Automatic boxes give less engine braking so you may have to brake gently on the down side of a rock. It's easier to maintain a slow steady momentum than to start off again after a stalled engine. You need to know where all your wheels are and where they will be a few feet further on. Pick a course to avoid getting high-centred. If in doubt, move a rock or pack smaller ones near it.
Sand
Moist or wet sand is not a major problem. If you can see tyre patterns then the sand is firm, but if tyre tracks are narrow vies then the sand is soft. Check that there isn't mostly dry sand just below the surface. If following a vehicle which is breaking through a thin crust, don't follow in their tracks; drive your own crust - less chance of losing critical momentum. The golden rule in soft sand is to MAINTAIN MOMENTUM, AVOID BRAKING and SHARP TURNS. When starting off, do it slowly, even slipping the clutch if necessary -in automatics use 2nd gear. Never change gear or slip the clutch when under load - you will come to a stop quickly. You may need a running start to get the required momentum but you should be in the highest gear that will do the job but we are not talking SPEED here. Reducing tyre pressures by half reduce the requirement for momentum. This is where compressor air pumps are useful! A spinning wheel will dig the vehicle down to the chassis in seconds. If you come to a stop, get out and take a look first, you may need a recovery technique, don't try to power your way out. On sandy steep descents accelerate out of a slide don't brake. Drive straight up or down a dune, don't traverse it and don't drive blind over the top of one. Desert terrain is most easily judged when the sun is low or when the spot lights are placed high on the vehicle. Don't drive through a sand storm - park the vehicle downwind and sit it out. Drive corrugations at the best speed to minimise vibration. If you drive sand regularly, invest in a long handled shovel.
Snow
The secret is to use a low enough gear to keep the engine revving happily, to maintain momentum and avoid changing gear unnecessarily. Remember snow can hide rocks, branches, frozen streams etc. Drive the crown of the track, leave a wide margin for ditches and keep to the high side on a slope.
Turn the steering left and right if climbing and you begin to loose traction. Don't change gear on ice. Drives down a snow slope don’t coast down and then you will maintain control.
Driving through slush in freezing conditions can cause ice to build up around the steering and suspension. In remote areas in winter it makes sense to plan for overnight survival.
The Environment
Care for the land you drive over. Don't use more aggressive tyres than is necessary, lower tyre pressures on fragile land. Don't make tracks, follow the ones that exist. Four driven wheels spread the traction effort needed and are less damaging than two driven wheels. Don't travel in large groups and be aware of the interests of wildlife.
Safety Tips When Taking Your Vehicle Off-Highway
Remember to breathe frequently and sit back and enjoy the ride. All too often, I find people stressing out and clutching the wheel hunched over with the back and shoulder muscles tensed. Relax. That is what you are in the bush for, right? The Zen of the destination is the journey!
Drive as slow as possible, but as fast as necessary. There are times when in soft sand like beaches and washes, speed needs to be moderate and flotation through mud and snow needs to be kept up, hence "as fast as necessary." But usually taking your time on the trail will allow you to pick a smooth path and allow you time to react/act to the varieties of terrain like moving rocks and logs under the tires. If you have a ground clearance deficiency, going slow helps here, in that, if you do hit a rock with the diff or other rock grabber, it will usually stop the vehicle on impact or you will lightly scrape over it. If you were going too fast and hit a rock or other obstacle, it could knock a hole in the oil pan, diff or even knock off the oil filter.
Don't get caught up in the Camel Trophy syndrome. They don't use those rigs as daily drivers. At the end of those events, the keys are handed over to a mechanic and a corporation that has deep pockets to refurbish them. Plus, you could get hurt!
Survey the trail ahead to avoid any "surprises." When in doubt, get out and recon! Make sure the trail goes beyond the obstacle, doesn't become a bottomless quagmire, has no back side to the hill (cliff?) or just plain ends. You can get a good idea where to place your tires and the differentials and have a plan of approach. And follow through to beyond the obstacle.
Don't stop in the middle of the challenge to check it out.Get through it, then walk back and check it out again. See where you actually went. Observe your tire tracks.
Drive directly up and down hills. Traveling diagonally may result in a sideways slide -- worst case, a rollover.
Know your approach and departure angles, the bumper to tire distance. Some trails will require off-camber driving. Just go slow, keeping the tires in the tracks. Don't lose attention and climb up a rock or stump on the up hillside. Vehicles will tend to slide sideways before rolling over. The tires will slip sideways a little. Stop if the slide puts you off the edge of the track. If it is clear downhill and a rollover is imminent, immediately turn the vehicle into the slide and drive it down. If that is not an option, and you are going over, turn the vehicle off and hold on to your seat-bottom and hope the seat belt works properly. You did have it on? There are other scenarios, but this is the least drastic. Use enough momentum to get up and over the hill. Avoid high centering on the crest. Use the engine brake method for the descent.
DO NOT TURN AROUND WHEN ON A HILL. Rollover CAN happen. Practice backing down.
Reduce the tire pressure. This improves traction in all conditions, especially sand. Remember that ground clearance has been compromised. Reinflate before driving on the pavement for any distance.
The easiest way to improve off-highway traction and performance is to "air-down." Depending on the tire you have and type of vehicle, you could go to as much as 1.5bar, even lower, if needed; for soft sand, 1bar.
Be careful to not turn fast and push the tire off the bead.
Read the manufacturer's label. The air pressure difference between the front and rear is due to the tire and auto manufacturers' experimentation for over/under steer and load variances. Carry a mini-compressor to reinflate, or know that an air pump is not far from the trail end.
Cross ditches or logs at an angle so that one wheel at a time goes over the obstacle; the other three help the one wheel to climb over. Dropping the tire into a ditch or crack in a rock is scary! Sometimes the vehicle pitches and one or more tires will catch air. Be very deliberate and careful when approaching this challenge section of any trail. Logs can bounce up and catch the undercarriage, so come off these things slowly and carefully. Turn the vehicle at an angle to facilitate the one tire at a time approach. Be careful not to allow one of the front tires and one of the rear tires to get in the ditch at the same time.
Get to know your vehicle and its performance potential. SQUEEZE the accelerator gently to avoid wheelspin, backing off the pedal when spin does occur, then gaining traction again. A spinning wheel/tire combo, no matter how large, does not give traction. That dirt pile doesn't know the difference from a Mud terrain or a Duel terrain tyre if it is spinning. You still won't get traction. You can't steer, brake or go with a spinning tire! Feel the point where the vehicle is about to stall, squeeze the throttle lightly, then back off the throttle, especially during rock crawling, up hill and snowed-in trails. With automatics you may have to use the left foot on the brake sometimes. Usually when you take your foot off the accelerator, the vehicle seems to "stall," so you put your foot back on the gas pedal and then the vehicle goes too fast. This "herky-jerky" method can be avoided by using finesse with left foot braking and proper throttle modulation. Know your vehicle and the actions and noises of the engine and suspension as you go over the trail.
Avoid lengthy wheelspin; digging into the track only gets you more stuck and ruins the environment. If stuck into the track, use a jack to lift the vehicle. Build up the ground under the tires. Placing brushwood and blankets, etc. under the tires will sometimes help with clearance. On the other hand, once in a while, you will have to let the tires "dig" a little to help forward momentum. If you feel the vehicle starting to lose traction or forward motion, try backing off the throttle then giving a short "blip" on the throttle. Try this a few times in quick succession. If this fails, back up and get another look at the obstacle and try a different approach.
When you think you are getting stuck and the driving tricks don't seem to be helping, immediately back out of the obstacle. Use the winch to get through or go somewhere else. Don't drive off the trail and around the challenge unless there is a legitimate by-pass.
Rocking the vehicle back and forth only serves to dig you in deeper. Sometimes it helps to rock back and forth, then to back out of the obstacle, but usually I don't like to dig deeper. Check under the vehicle to see what is holding it; a rock? a stump? or other grabber thing? Make sure those things are clear before winching or using the recovery strap. I always carry a well-stocked recovery kit!
Keep the use of the brakes to an absolute minimum to keep the wheels from locking up on wet, muddy, loose rock Descend steep slopes in low range and first gear. Rely on engine compression to slow the vehicle. If sliding occurs, drive the vehicle forward to gain traction once again, then back off the throttle. Sometimes when in extreme rocky descents with ledges and shelf steps, the clutch must be pushed in and the brakes used to allow the vehicle to creep forward ever so slowly. This should only be done in those cases. Usually engine control through throttle modulation is best served by engine compression on descents. A locked sliding tire gets no traction.
BEWARE of the LURCH and SURGE! Unless you have lockers engaged on both axles, the lurch and surge will scare the heck out of you until you have experienced it many times. When in gear, no brakes, and open diffs, the vehicle has traction from only one tire on an axle--you know what happens when going uphill and getting traction to only one tire per axle. Well, when going downhill, if the tire that has contact to the transmission gets air or slides, the vehicle will lurch forward because the non-tractive tire has no resistance from the gear box. Usually it is a short surge, and control is gained when the tire contacts good terrain. When that is likely, a light foot pressure on the brake pedal will help to prevent the next lurch. The vehicle will actually "shoot" forward fast for a short distance. If not controlled or anticipated, you could gain momentum and quickly get out of control, especially on long descents.
The same happens when backing down off an ascent as well. When backing down, always be in reverse gear. The same procedure pertains as in the descent. This is especially important when backing down, as the front end becomes light and the steering tires won't give the afforded traction for steering, traction and braking.
Do not oversteer - especially while in ruts or deep tracks. The steering wheel may look centered, but the tires may be at full turn. Murphy's law says-when traction is gained, there will be a big tree or rock at that point. Driving on a trail, many obstacles will be encountered that will move the steering wheel all around. The tire gets lifted up or drops down in a hole and causes the steering wheel to move as if it were turning on a curve. This "wallowing" of the front end and "bump steering" creates the false impression that you must correct the original steering course. Get used to the feeling of the front end articulating over the trail, and hold the steering wheel on-center. Just hold the wheel firmly and "aim" the rig over the trail in those rough sections.
What happens is the steering wheel gets tugged to one side, you correct to the other side, then the next minute the wheel comes right back and you have to correct it again, or actually re-correct it. Now, all you are doing is over-correcting and turning the steering wheel back and forth, wearing out your arms! You do have to steer on the trail and keep the rig centered, but don't oversteer! When in mud or deep ruts, sometimes quickly turning the steering wheel so that with your hands at the "3 and 9" position, you move it halfway round and back almost touching your wrists in a cross over position. This will make the front tires turn back and forth, causing the sidewall edges to help claw their way through.
Make slow, steady progress through deep water to create a "bow wave" and an air pocket in and around the engine compartment and front wheels. This minimizes risk of water drowning the engine. Water does not compress as well as air. Don't let hydrostatic lock ruin your day. Check the brakes after coming out.
Having a plastic sheet or poncho to cover the front of the vehicle, especially around the radiator grill, will help keep most of the water out of the engine bay. Smooth progress through deep water or mud will keep the air pocket stable. A big rock or drop-off will affect the steady progress and "burst your bubble," so be careful! Generally speaking, a deep crossing should be no more than just over the tires. Mud that deep will stick you before the front axle gets half-way. Carry an extra air filter element in case you do drown the engine. Get the vehicle out of the creek, then work on it.
If the engine does swallow some water pull the spark plugs, air filter. Crank the engine over and blow the water out of the cylinders. Check the engine oil before cranking! I have seen the engine completely fill with water. You might have to drain the engine, so do it for the environment and use water jugs or coolers to collect the watered oil.
Glossary of 4x4 terms
A-arm Triangular-shaped suspension component with two pivot points connected to the truck's frame and one point attached to the spindle.
ABS Antilock Braking System
add-a-leaf An extra spring leaf that is added to the spring pack.
after-cat system An aftermarket exhaust system that attaches to the outlet side of the catalytic converter and generally consists of a free-flow muffler, new tubing, and mounting equipment.
airbox Enclosed chamber that routes fresh air to the carburetor or intake manifold. Some trucks use an airbox with an integral filter; some use a remote filter at the airbox's intake duct.
air dam Full-width panel just below the bumper, designed to reduce or modify airflow under the truck, which improves aerodynamics but limits ground clearance.
air-down To lower the air pressure in tires. Airing down increases traction and smooths out the ride over rough terrain.
air/fuel mixture The ratio of air to gasoline that makes the fuel mixture. Theoretically, the perfect ratio is 14.7:1.
Air Locker A selectable locking differential manufactured by ARB that uses compressed air to engage the side gears.
all-wheel drive (AWD) A system in which all four wheels are driven but that lacks a multirange transfer case.
analog Gauge or display that shows a reading such as mph, rpm, or fuel level with a dial and moveable needle indicator.
anodize To apply a colored or clear oxide coating to an aluminum component through an electrical charge.
antisway bar Suspension component that prevents excessive side-to-side body sway. Syn. sway bar.
approach angle The maximum incline angle that a truck can climb or descend without hitting its front.
ARB 1. Air Resources Board. 2. Manufacturer of the Air Locker differential and other off-road products.
aspiration An engine's breathing system.
axle hop When a truck's axlehousing rotates opposite the direction as the tires under acceleration, then snaps back to its original position relative to the chassis. Sometimes, this motion is repetitive until the driver reduces the degree of acceleration. Syn. axlewrap.
axlehousing Exterior nonrotating housing that contains the axleshafts, differential, and the gears that drive the wheels.
axlewrap A condition where the rotational load from an axle is placed on the leaf spring. Springs are flexed into an "S" shape, storing spring energy until the tires slip.
backpressure Resistance to the free flow of exhaust gases.
backspacing The distance between a wheel's outer inboard edge and its mounting flange.
baffle 1. Plates, panels, or barriers inside a muffler that reduce sound. 2. A condition resulting from mysterious vehicle vibrations.
balance tube Short, laterally positioned pipe connecting the exhaust pipes on a dual-exhaust system. Used to equalize gas pressure between the two pipes.
ball joint A flexible joint consisting of a ball used in a socket, mainly in front suspensions because it can accommodate a wide range of angles.
BDC Bottom Dead Center, the lowest point of a piston's travel within the cylinder.
bead 1. The inner lip of a tire that attaches to the wheel. The exterior rubber bead conceals an embedded wire reinforcement. 2. In welding, a narrow half-round line where two pieces of metal have been joined.
bead lock A two-piece system that clamps the tire to the rim, especially helpful when airing down your tires for off-roading.
beater A truck that is rough or dented on the outside but might be mechanically sound. Syn. Bomber.
beefed-up 1. A 4x4 that is stronger than stock. 2. An after-dinner condition on the trail.
beltline 1. Body line running from front to back on a truck's side that visually separates the lower body from the lower edge of the greenhouse, the roof, and window assembly. 2. A measurement that increases as we get older.
bench race To talk about your truck and your driving feats as if they were fish stories.
bezel Trim ring, usually chromed or polished, that surrounds headlights or gauges.
bicycle To ride on either both right- or left-side wheels.
bikini top 1. A soft top that covers only the front seats and leaves the rear uncovered. 2. What many of us like our significant others to wear on the trail.
bellhousing Bell-shaped enclosure for the clutch and flywheel on a manual transmission or the flexplate and torque converter on an automatic transmission.
billet A part machined from a single piece of metal, not a casting.
bleed 1. To remove air in a hydraulic system by pumping out fluid. 2. What hands often do while working on trucks.
blip Quick touch of the throttle to momentarily rev an engine.
blower 1. Supercharger. 2. Ventilation system's motor.
blown engine 1. A seriously damaged engine. 2. A supercharged engine.
blow the doors off To defeat a competitor during a speed contest.
blueprint To rebuild an engine to its OE design specs, machining and checking the weight, size, and fit of each component against a factory blueprint.
bobbed The rear of the truck, SUV, of Jeep has been shortened, usually adjusted for better departure angle.
body roll 1. Tendency of a truck's body and chassis to lean toward the outside of a turn as the result of cornering forces. 2. The flesh that protrudes over our beltlines.
bog 1. Running an engine below its intended operating range by driving in too high of a gear for the speed or load. 2. The mud pit at a mud-bog race.
bogger 1. A vehicle built for mud racing. 2. One who mud-races. 3. (cap.) Type of tire
boiling the balonies Spinning the tires.
bolt-on Aftermarket part or component that can be installed without special modifications or major disassembly.
boneyard 1. Wrecking yard, junkyard, salvage yard. 2. The Back 40 of many 4x4 owner's homes.
boost The increase in intake pressure above atmospheric pressure provided by a supercharger or turbocharger. Boost is measured in psi.
bore 1. The diameter of a cylinder. 1. The act of machining a cylinder to fit larger pistons.
bored-and-stroked Combination of an enlarged cylinder bore and a lengthened piston stroke, resulting in an increase in overall engine displacement and power; rarely boring.
bottom end 1. The crankshaft, connecting rods, and main bearings of an engine. 2. Power at low engine speed.
bottom-out When the truck's suspension is fully compressed and its bumpstops won't allow further suspension travel.
boxed Strengthen a frame by adding a metal plate to an open-channel framerail or crossmember, thereby turning a three-sided framerail into a four-sided rail.
brake fade A loss of braking power, the result of the brakes' friction surface or the brake fluid becoming overheated.
broach to pierce or open, sometimes referring to a splined cut on a gear or flange.
bulletproof An allegedly indestructible truck or component.
bump 1. A horizontal obstacle. 2. To blip the accelerator. 3. To back off an obstacle, then hit it again with momentum.
bumpsteer A situation in which the steering jerks when a truck encounters a bump in the road. Bumpsteer is often caused by improper steering geometry.
bumpstick Camshaft
bumpstop Rubber or urethane block used to limit suspension compression travel.
burnout Deliberate spinning of the rear tires to heat and clean the tires' tread in preparation of maximum acceleration from a standing start. Can also be used to impress onlookers.
butt-scratcher A trail obstacle that scrapes on a truck's rear end.
cam 1. An eccentric device which converts rotating motion to reciprocating movement 2. Camshaft.
camber The tilt of the front tires toward or away from the center of the truck relative to vertical. When the top of the tire leans out the camber is positive; if the tire leans inward, camber is negative.
cam duration Amount of time, expressed in degrees of crankshaft rotation, that a cam holds open the intake or exhaust valves.
cam lift Distance, expressed in thousandths of an inch, at which a cam opens the valves.
candlepower A light brightness rating. Not all manufacturers use the same method to determine candlepower.
caster The fore or aft tilt of the steering axis relative to vertical. Lifting a truck can cause too much negative caster, which results in wandering.
catalytic converter An emissions-control device that routes exhaust gases through an oval-shaped canister filled with palladium and platinum pellets, thereby converting the toxic exhaust gases to water vapor, carbon dioxide, and less-toxic gases. Syn. cat.
CB Citizens band radio. A two-way radio commonly used for communication between trucks on the trail.
center disconnect A four-wheel-drive system that engages the front axles at an inboard location rather than the outboard hubs.
center of gravity The theoretical center of mass in a vehicle. It can change dramatically due to passenger load and cargo.
cherry Clean, in unusually fine shape.
CFM Cubic feet per minute, generally used to measure airflow through a port, intake manifold, or carburetor; a system used to determine carburetor and fuel-injection capacity.
chaindrive A system in which a chain and sprockets drive gears instead of the gears being meshed together.
chick-deflector Repulsively ugly vehicle. Ant. chick magnet
chicken-handle A handle for passengers to grab when the going gets rough; also known by other, unprintable names.
chip A computer's microprocessor, computer. A nick in the paint.
chirp the tires To shift quickly during hard acceleration so that the tires momentarily lose traction.
chunk 1. Slang for the ring-and-pinion gear assembly inside a differential housing. 2. When parts eject from their functional location.
clip A truck's entire front sheetmetal section, including the fenders, hood, and cowl.
coilover A suspension that uses shocks with an integral coil surrounding the shock body, often used with custom-fabricated multilink suspensions because they offer the advantages of easy preload and ride-height adjustments, lots of wheel travel, and accurate spring dampening rates.
collector Device that collects exhaust gases from the exhaust manifold's (or header's) primary tubes and routes them into a single-exhaust pipe.
combustion chamber A cavity within the cylinder head(s), just above the piston(s), where combustion takes place.
compression ratio The ratio of cylinder volume with the piston at BDC to the volume remaining in the cylinder chamber when the piston reaches TDC. The greater the difference, the higher the compression ratio, generally producing more power. If the compression ratio is too high, however, it can cause detonation and an increase in pollutants.
contact patch Portion of a tire tread in contact with the road surface.
Cornbinder Slang for any 4x4 made by InternationalHarvester because the company is known for making farm equipment. Syn. 'Binder.
crank it 1. To turn the steering wheel hard left or right. 2. To start the engine.
crankshaft Shaft with large, U-shaped cranks that are connected to the pistons' connecting rods and transforms the pistons' reciprocal motion to a rotational motion, which powers the drivetrain. Syn. crank.
crawl-ratio The lowest gear ratio in the truck, found by multiplying the First gear ratio of the tranny by the low-range gear ratio of the transfer case by the axle gear ratio.
cross-drilled crank Crankshaft with additional lubrication holes drilled opposite the existing main journal oil feed holes, providing improved high-rpm-bearing lubrication.
curb weight Total weight of a truck with the fuel tank full, the engine oil at its proper level, and the cooling system full, but without a payload or passengers.
CV joint Constant velocity joint, two U-joints in tandem or a Rzeppa joint which allows for increased angularity of driveline components. Commonly found on front driveshafts and front-drive axles.
cylinder head The part of an engine that contains the valvetrain and the combustion chambers and covers the tops of the cylinders and pistons.
deck The surface of the engine block on which the head gasket and cylinder sit.
degreeing a cam Using a dial indicator and a degree wheel to verify that a cam's lift and duration is accurate.
departure angle The maximum angle a truck can descend before hitting the rear bumper or other components located behind the rear tires.
Detroit Locker A popular brand of automatic locking differential.
dial-in 1. To set up a truck's engine, chassis, drivetrain, stereo, or other system so that maximum performance results. 2. To set up a mechanical component for trouble-free operation.
direct ignition system Ignition system that has no distributor; ignition is sent directly from the multiple modulators (coils to the spark plugs).
directional tire Tire with an asymmetrical tread that is designed to produce superior traction when rotating in one direction only.
double-line A type of winch rigging that runs the cable to an anchor point and back to the vehicle, thereby doubling the pulling power.
Double-pumper A four-barrel Holley carburetor with mechanical linkage to open both the primary and secondary barrels and mechanical accelerator pumps in both the primary and secondaries.
drag link Steering link that connects the pitman arm to the steering arm.
droop Any downward suspension travel.
drop the hammer To accelerate rapidly from a stop.
dropped pitman arm An offset arm that lessens the angle between the steering box and drag link.
dualie A truck that has dual rear tires on each side.
dual plane An intake manifold with runners that do not share a common plenum, usually designed for low- to midrange engine performance.
dyno Abbreviation for dynamometer, a machine used to measure engine torque either at the flywheel (engine dyno) or rear tires (chassis dyno).
ECU Electronic Control Unit, computer unit for engine management.
EFI Electronic Fuel Injection; computer-controlled fuel delivery system.
EGR Exhaust Gas Recirculation, an emissions-controlled device that reintroduces burned exhaust gases to an engine's combustion chamber.
electronic ignition Ignition system that uses transistorized circuits instead of breaker points.
E.O. Number Executive Order Number, the number assigned to a part by the California Air Resources Board when it becomes legal to use on emissions-controlled vehicles.
exhaust backpressure Resistance to the free flow of exhaust gases through an exhaust system
exhaust headers Performance exhaust manifold built from equal-length steel tubes that is designed to speed the flow of exhaust gases exiting the cylinder head(s).
exhaust manifold Tubular cast-iron component that routes exhaust gases from the cylinders to the exhaust system.
fairlead A steel guide installed onto a winch mount to help direct the winch cable. Fairleads come in two styles: roller, which uses steel rollers, or Hawse, which features a simple bracket with large radiused edges for the cable to ride against.
fan clutch Thermostatically controlled clutch device that engages or disengages a mechanical radiator cooling fan according to the engine's cooling needs.
flathead An early engine design that located the valves in the block beside the cylinders, rather than the head (overhead valves) as is currently done.
flat spot Momentary decrease in engine power at some point within the powerband.
flat-top 1. A piston without a dish or a dome. 2. A popular '50s haircut.
forced induction Supercharged or turbocharged
four-banger A four-cylinder engine.
four-bolt main A crankshaft's main bearing caps held in place by four bolts.
freewheeling When the front hubs are unlocked and the wheels spin because of momentum rather than power.
fuelie Old slang referring to a fuel-injected engine or vehicle.
fuel injector Electromechanical device that squirts fuel into an engine.
full-floater An axle assembly designed to hold the weight of the vehicle on the axlehousing instead of on the axleshafts; has bearings at both the differential and wheel ends.
gas shock Damper shock absorber with two separate compartments, one containing hydraulic fluid, one containing nitrogen gas. The gas keeps pressure on a flexible, in some cases, moveable separating disc, that, in turn, keeps pressure on the fluid, thereby reducing the fluid's tendency to foam during aggressive driving.
g-force Measurement of the force generated during cornering, acceleration, or deceleration, expressed in units of gravity.
glasspacks Tubular style of muffler that uses fiberglass packing to absorb sound.
gnarly A difficult portion of a trail that may or may not make you nervous. Syn. exceptional.
granny gear An extremely low First gear in a manual transmission. For example, an SM465 has a 6.55:1 First gear ratio.
grenade Catastrophic failure of an expensive part. Engines, transmissions, and axle assemblies can all grenade.
greenhouse Upper portion of a truck's body; the structure above the beltline, including the roof, windows, and pillars. Syn. office.
ground effect Reduced airflow under a truck provided by an air dam and side skirts. Less pressure underneath a truck allows the air passing over its top to push downward, thus creating an improved grip on the road as well as improved top speed and fuel efficiency. Impedes ground clearance in 4x4s.
gumbo Deep, sticky mud.
gun it To deliberately rev an engine.
gusset Triangular metal support used to add strength; is welded in place where two framerails connect or where two tubes of a rollcage are welded together.
GVWR Gross Vehicle Weight Rating, the combined weight of a vehicle and its rated cargo capacity.
halogen light High-output headlight or driving light that has halogen gas inside the bulb. When surrounded by a halogen gas, the bulb's tungsten filament can carry a higher current, thus producing a more brilliant white light.
hammered 1. A truck that's thoroughly destroyed. 2. A truck that has a chopped top or a severely lowered suspension.
handle The nickname you use on the CB.
H.E.I. High-Energy Ignition, a powerful and reliable GM distributor assembly with a self-contained coil.
Heliarc welding A form of tungsten inert gas welding used primarily on aluminum and stainless steel.
Helicoil Stripped thread repair system, consisting of small coil-spring inserts that thread into place on damaged female screw threads.
high-centered When a truck is firmly stuck, usually caught on its frame on an obstacle unable to move.
high-pinion See reverse-rotation.
hi-Po High-performance.
hole shot Beating a competitor at the start of a race; coming off of a dead stop quicker; coming out of the hole quicker.
hook up 1. To gain traction. 2. To gain a date.
hub Wheel mounting surface.
huffer A beltdriven supercharger.
hydraulic'd Past tense only, said of an engine that has been submerged in water and has sucked water into its cylinders through the intake and will no longer rotate because the pistons moving up the cylinders cannot compress the water.
IFS Independent Front Suspension, a type of suspension system that allows the two tires on one axlehousing to move separately from one another.
intake ports Passages within a cylinder head that route air and fuel to the intake valves.
juicebox An automatic transmission.
kick-down Quick downshift on an automatic transmission when the engine is given full throttle.
kicker shocks Shocks mounted in a near horizontal position between the axlehousing and the leaf springs. Kicker shocks are valved with a high rate of compression damping and are intended to reduce axlewrap.
kick-up Section of a frame that is curved up to clear an axlehousing.
ladder bars Longitudinal suspension control arms that connect the axle to the frame, preventing axle wind-up and hop.
lash Amount of clearance between a valve and a rocker arm or between a rocker arm and a lifter or pushrod.
lateral link Tubular suspension rod that positions the axlehousing so that side-to-side movement is minimized during cornering.
LED Light-emitting diode, a small semiconductor that lights up when current is passed through it. Used on some dashboard displays and taillights.
lifted Any 4x4 that is raised either by a suspension or body lift.
lift-block A spacer placed between the axle assembly and the springs to lift a truck inexpensively. These are only safe on rear-axle assemblies.
light it off Start an engine.
limited-slip differential Final-drive system where the two axleshafts are mechanically connected with a series of clutchlike plates to prevent wheelspin on slippery surfaces and to ensure that the engine's power is transmitted equally between the two tires.
line A driver-selected path that gives a truck the best route to climb over an obstacle or through a pathway. Choosing the right line is essential to successful four-wheeling.
locked in To have engaged the manual front hubs into the lock position.
locker A device in either the front or rear differential that sends engine power to both wheels regardless of traction.
lockers front and rear One of the most common truck-owner fibs.
Loctite A product used on fasteners to maintain torque.
long-block Engine assembly consisting of a cylinder block, a crankshaft, a camshaft, bearings, pistons and rings, connecting rods, an oil pump, an oil pan, a timing cover, seals, cylinder heads, and an intake manifold.
loud pedal Accelerator.
low gears Gears that increase the amount of reduction in the transmission, transfer case, or axle. In an axle, they are expressed as the ratio of ring-gear teeth to pinion teeth, so low gears are numerically higher than high gears. (Example: 4.10 gears are lower than 3.55 gears.) Rockcrawlers typically have low gears.
low-lock To have the transfer case in 4-Lo therefore locking out the center differential, if so equipped.
mandrel bend Hydraulic or mechanical tube-bending machine that uses dies and mandrels (forms) to bend tubing in such a manner that the walls don't collapse.
manifold cooking To use a hot intake manifold as a heat source for cooking on the trail. Burritos and cans of beans or chili are favorite manifold delicacies.
MAS Mass Airflow Sensor, a device that measures the amount of airflow into the intake manifold. This information, as well as data from other sensors, is sent to the engine's computer, which calibrates the optimum air (fuel and adjusts the EFI system as required.
meats Tires, particularly large, aggressively treaded ones. Syn. skins, shoes.
MIG welding Metal Inert Gas welding is a wire-feed welding system that uses argon gas as a shielding agent for the weld. Steel, stainless steel, aluminum, and other metals are commonly welded with a MIG welder.
mill 1. Engine 2. Milling machine.
modular wheel Custom or racing wheel with an inner, an outer, and a centersection that are bolted or riveted together.
monochrome Styling inspired by European performance cars where the bumpers, grille, body trim, and door handles are painted the same color as the body.
mountain motor Big-block engine, typically bored and stroked to at least 500 cubic inches.
Mouse motor Chevy small-block V-8 engine, named Mouse because of its small overall physical size, and because, some say, GM executives wanted to scare Chrysler's "elephant" Hemi engine with the new, powerful small-block Chevy.
Multilink Solid-axle suspension design where coil springs are used instead of leaf springs, and the axle is located by longitudinal and lateral suspension control arms, or links.
nail it To apply full throttle.
negative offset When the wheel's mounting surface is outboard of its centerline.
normally aspirated An engine that relies on vacuum through its intake manifold and cylinders to draw in an air-fuel mixture; an engine without a forced-induction supercharger or turbocharger.
NOS 1. New old stock; original equipment, unused parts for vintage trucks, often found in their factory cartons at dealerships. Ant. repro, reproduction. 2. A nitrous oxide injection company. 3. Slang for nitrous.
OEM Original equipment manufacturer. Syn. stock.
off-camber A situation in which the truck is sideways on an incline, increasing the likelihood of a rollover.
oil gallery Small passages within the engine block and cylinder heads through which lubricating oil circulates.
one-off 1. Custom part or component that is fabricated from plans; no other identical copy exists. 2. Wide-production modifications to an existing vehicle, such as a Saleen Explorer.
out to lunch Worthless, a truck that doesn't run well or look right.
oversteer Cornering condition where the rear tires slide toward the outside of the turn.
Panhard rod A transverse link (rod that attaches to the truck's frame at one end and to the axlehousing at the opposite end), providing lateral positioning of the axlehousing relative to the chassis.
paperweight A part that's broken beyond repair can be used as an excellent paperweight.
payload Maximum weight a truck can carry, calculated by subtracting the curb weight of the truck and a 150-pound allowance for each passenger from the gross vehicle weight rating.
peg-leg An open differential. Syn. one-legger.
pickle fork Fork-like tool used to separate suspension components, such as ball joints and tie-rod ends, for repair.
pinion angle The angle of the pinion yoke on an axlehousing in relation to its driveshaft.
pitman arm Steering lever that converts the rotary motion of the steering box to the linear motion of the steering system's centerlink.
plenum Box or cavity at the intake manifold's entrance that stores the air/fuel mix for distribution to the intake runners.
plow Understeer.
port injection Electronic fuel-injection system that injects fuel directly into the cylinder-head ports.
posi Short for Posi-traction, a limited-slip differential used by General Motors. The term is often used generically for any limited-slip device.
positive offset When the wheel's mounting surface is inboard of its centerline.
prerunner An off-road truck that's built to prerun a desert race course so that the driver can study and practice on the course before the race.
progressive-rate springs Suspension springs that become progressively stiffer as they are compressed.
proportioning valve Hydraulic braking valve that varies the braking force at the front or rear wheels, depending on pedal pressure, load, and weight transfer, to reduce or eliminate wheel lockup.
P.T.O. Power take-off, an accessory powered by engine output, usually a winch.
pumpkin The centersection of an axlehousing that contains the differential carrier and gearset. Syn. coconut, third member.
pushrod Thin metal rods that transmit the motion from the camshaft and lifters to the rocker arms, and thus operate the valves on an overhead-valve (OHV) engine.
quad 1. Four-barrel carburetor. 2. A four-wheeled all-terrain vehicle.
quarter-panel Body shop term for the front or rear corner sheetmetal assembly.
radius arms Brackets used by Ford that locate the front axlehousing on coil-spring suspensions. Dodge and Jeep use similar brackets. Syn. trailing or control arms.
rack-and-pinion A steering system that uses a pinion gear at the end of the steering shaft to engage a horizontal-toothed bar, the rack, which is attached to the tie rods and the steering knuckles.
rake When the frontend of a truck sits lower than the rear.
ramp breakover angle The angle formed by lines drawn from the front and rear tires' contact patches and the midpoint of the wheelbase on the chassis; the greater the angle, the less likelihood of high-centering.
Rat Chevy big-block V-8 engines, normally offered in 396ci, 402ci, 427ci, and 454ci sizes. Named because it was a large companion to Chevrolet's small-block Mouse V-8.
rebound After a suspension spring is compressed by a bump, the spring naturally tries to return to its previous length, extending the suspension upward toward its original ride height.
recirculating ball steering Steering assembly that uses a worm gear on the end of the steering shaft to turn a sector gear that is within the steering box and attached to the pitman arm. Ball bearings are used between the worm and sector gears for smooth operation.
redline Absolute maximum engine speed, expressed in rpm, at which an engine can/should be operated; indicated by a red line on the tachometer. Syn. rev limit.
repro Aftermarket reproduction parts, manufactured to appear, fit, and function as originals. Not the same as OE or N.O.S., which are both factory-issued parts.
restify To build a truck that is basically restored but has been updated with modern convenience and performance enhancements.
retrofit Installing new parts or systems on an older truck for the purpose of upgrading, such as retrofitting a modern fuel-injection system in place of the original carburetor.
rev limiter An adjustable electronic device that restricts engine rpm to a predetermined limit so engine damage does not occur.
reverse-rotation Refers to an axle design where the pinion is positioned above the axle centerline.
ring-and-pinion Gearset that drives the wheels; the pinion is a gear attached to the rear of the driveshaft, and the ring gear is part of the differential that turns the axles.
rock magnet A low-hanging component of a 4x4, such as a ladder bar, that seems to catch on every obstacle.
rock massaging Body damage caused by rocks and other obstacles on the trail.
rocker arm Pivoting valvetrain levers. One end of an engine's rocker arms are moved by the pushrods/lifters and the opposite end's open intake or exhaust valves.
rocker panel The sheetmetal section of a truck's body located below the doors and between the front and rear wheel openings.
Roots supercharger Positive-displacement, beltdriven supercharger; originally designed in 1859 by Francis Roots for use as a water pump.
RTI Ramp travel index, a measurement of suspension flexibility and articulation that's calculated by dividing the distance the hub's centerline travels up a (usually 20-degree) ramp by the vehicle's wheelbase in inches, multiplied by 1,000.
sanitary Well designed, engineered, and constructed; cleanly built; superior mechanical workmanship. Syn. sano.
semi-floater An axle assembly that carries the weight of the vehicle on the axleshafts. These are typically weaker than full-floaters.
serpentine belt Engine accessory drivebelt that is long and follows a snaking path while driving the alternator, water pump, A/C unit, and power-steering pulleys.
shackle Connector between the rear of a leaf-spring pack and the frame; allows the spring to lengthen as the suspension is compressed.
shift kit Package of high-performance components for an automatic transmission that firms the shifts, alters the shift points, and improves overall performance.
shiny-side down When a truck rolls over. Syn. rubber-side up.
short-block An engine block that has a complete bottom end, including the crankshaft, rods, pistons, and camshaft, but without the cylinder heads, intake and exhaust manifolds, water pump, and other accessories.
sidehill A portion of a trail that leads across a steep hill instead of up or down. See off-camber.
single-plane manifold Intake manifold with a single plenum feeding all of the engine's intake runners.
skin Body sheetmetal.
skins Tires.
slickrock A type of sandstone dominant in Moab, Utah. Slickrock actually isn't slick and provides excellent traction.
slushbox An automatic transmission. Syn. juicebox.
small-block A V-8 engine typically having 400 or less cubic inches of displacement.
snatch-block A pulley device used in assisting with getting unstuck; it doubles as a winch cable's pulling power.
snatch strap A thick nylon strap used to pull out stuck vehicles. Syn. tow strap, yank strap.
spool out To pull the winch cable off the drum after releasing the brake.
spotter A codriver who helps guide the driver over obstacles, often using hand signals.
spring rate The force required to deflect a spring 1 inch, expressed in pounds per inch of spring compression or deflection. The higher the per-inch spring rate, the stiffer the spring.
spun bearing A bearing that is either worn or frozen and has rotated in its retainer. In an engine, this causes the bearing to block off its oil passage and results in major damage.
stair-step An obstacle that contains one or more ledges that must be climbed in succession. Stair steps are common on trails that follow washes or creek beds.
stand on it Full-throttle acceleration.
swamped To drown the engine; to drown the entire truck.
synthetic oil Manmade lubricants; they generally have a greater capacity to lubricate and resist heat than standard mineral oil.
tachometer Device used to measure and display engine speed, expressed in revolutions per minute. Syn. tach.
tack welds Series of small welds, spaced approximately 1 inch apart, which are used to hold together two pieces of metal until the final welding can be performed.
taco'd Axlehousings, frames, or other components that have been severely bent, usually from jumping the truck.
tail gunner The last vehicle/driver on a trail ride. The tail gunner is responsible for making sure everyone completes the trail.
tall gears The opposite of low gears, they are represented in ratios that are numerically lower than "low" gears; e.g., 3.08s are taller than 4.10s.
TBI Throttle-body fuel injection.
threshold braking Applying as much pressure to the brake pedal as possible without going to wheel lockup.
throwout bearing On a clutch assembly, a shaft-mounted bearing that is moved from pressure on the clutch pedal and disengages the clutch disc from the engine.
T-case Transfer case.
tie rod Steering linkage between the pitman or idler arm and a steering arm that moves the steering knuckles.
TIG welding Tungsten Inert Gas welding, also referred to as heliarc welding, usually used for joining aluminum and stainless steel.
timing chain/gears Chain or gears that transmit rotation from the crankshaft to the camshaft.
toe-in, toe-out Inclination of a pair of front wheels slightly inward or outward as viewed from the truck's front.
torque converter Fluid coupling between the engine and the automatic transmission. The engine powers a fan-shaped impeller inside the torque converter, which splashes oil onto a turbine (another fan-shaped device), and the turbine transmits its power to the transmission's gearbox.
torsion bar Suspension spring that looks like a long metal rod. One end is attached to the truck's frame, and the other end is attached to the suspension's A-arm. When the A-arm moves, the torsion bar is twisted and then springs back to its original shape, thus its springing action.
TPI Tuned-port fuel injection.
trail boss The leader of a trail ride.
trailer queen A vehicle that's built primarily for show and is trailered to events.
TTB Twin-Traction Beam, a type of Ford front suspension that utilizes an axle assembly with pivot points, allowing the tires to move independently.
tunnel ram Intake manifold with a large plenum and long, straight runners, used for high-rpm engines.
turned turtle A truck that's rolled upside down.
two-bolt main Engine block with its main crankshaft caps held in place by two bolts.
two-wheeling When tires lift off the ground during a tricky maneuver. Syn. bicycling.
U-bolt U-shaped bolt commonly used to attach an axlehousing to a leaf-spring pack.
U-joint Mechanical joint that can transmit rotary motion while swiveling. Used at both ends of a driveshaft to transmit power from the transfer case to the differential.
understeer Cornering condition where a truck's front tires lose grip before the rear tires, causing the front end to slide or push toward the outside of the corner.
unglued 1. Damaged or destroyed; a blown-up engine has become unglued. 2. The codriver's mental state following a rollover.
vacuum advance Device that advances or retards ignition timing according to the degree of engine vacuum. At low engine speed, there is plenty of engine vacuum, so the ignition is advanced; at wide-open throttle, there is little vacuum, so the ignition remains at its original timing advance.
vacuum secondaries Secondary carburetor barrels that are pulled open by engine vacuum.
valve lift Circular, stemmed device used to control the airflow in and out of an engine; operated by the camshaft/pushrods/rocker arms.
valvetrain The valve lifters, pushrods, rocker arms, and valve springs.
vaporlock Condition where fuel boils within the fuel line or carburetor, causing bubbles to form that impede the fuel flow or cause excessive fuel to flood the carburetor.
variable-ratio steering Power-steering box that varies the steering ratio. At low speeds, the steering response is quicker for maneuverability; at high speeds, the steering ratio is reduced for stability.
ventilate the block To throw a connecting rod through the side of an engine block due to component failure or excessive revs.
venturi Carburetor barrel or throat with a slightly narrowed or hourglass shape to its interior. The small, narrowed area speeds up airflow and helps pull the fuel past the carburetor jets and into the air stream.
VIN Vehicle identification number, a serial number that identifies a vehicle.
wail To perform at peak power or efficiency.
wheel adapter Metal plate with wheel studs that allows a wheel with one bolt pattern to be used on a truck with a dissimilar bolt pattern.
wheelbase Distance from the center of a truck's front wheel to the center of the rear wheel on the same side.
wheel travel The total distance a wheel can move up and down; affected by suspension travel and wheelwell clearance. More wheel travel means a more flexible suspension and more potential traction.
white-knuckle An obstacle that is scary enough to make the driver grip the steering wheel extremely tight.
windage tray An internal engine shield, mounted close to the crankshaft and intended to deflect oil away from the crank as it rotates.
wiring harness Major part of a truck's electrical wiring system; a group of wires bundled together.
WOT Wide Open Throttle.
wrist pin Hollow metal tubular pin that attaches the piston to the connecting rod.
zerk fitting Nipplelike fitting on suspension and chassis parts and on U-joints, through which lubricant is pumped under pressure to lubricate the components' internals.
ABS Antilock Braking System
add-a-leaf An extra spring leaf that is added to the spring pack.
after-cat system An aftermarket exhaust system that attaches to the outlet side of the catalytic converter and generally consists of a free-flow muffler, new tubing, and mounting equipment.
airbox Enclosed chamber that routes fresh air to the carburetor or intake manifold. Some trucks use an airbox with an integral filter; some use a remote filter at the airbox's intake duct.
air dam Full-width panel just below the bumper, designed to reduce or modify airflow under the truck, which improves aerodynamics but limits ground clearance.
air-down To lower the air pressure in tires. Airing down increases traction and smooths out the ride over rough terrain.
air/fuel mixture The ratio of air to gasoline that makes the fuel mixture. Theoretically, the perfect ratio is 14.7:1.
Air Locker A selectable locking differential manufactured by ARB that uses compressed air to engage the side gears.
all-wheel drive (AWD) A system in which all four wheels are driven but that lacks a multirange transfer case.
analog Gauge or display that shows a reading such as mph, rpm, or fuel level with a dial and moveable needle indicator.
anodize To apply a colored or clear oxide coating to an aluminum component through an electrical charge.
antisway bar Suspension component that prevents excessive side-to-side body sway. Syn. sway bar.
approach angle The maximum incline angle that a truck can climb or descend without hitting its front.
ARB 1. Air Resources Board. 2. Manufacturer of the Air Locker differential and other off-road products.
aspiration An engine's breathing system.
axle hop When a truck's axlehousing rotates opposite the direction as the tires under acceleration, then snaps back to its original position relative to the chassis. Sometimes, this motion is repetitive until the driver reduces the degree of acceleration. Syn. axlewrap.
axlehousing Exterior nonrotating housing that contains the axleshafts, differential, and the gears that drive the wheels.
axlewrap A condition where the rotational load from an axle is placed on the leaf spring. Springs are flexed into an "S" shape, storing spring energy until the tires slip.
backpressure Resistance to the free flow of exhaust gases.
backspacing The distance between a wheel's outer inboard edge and its mounting flange.
baffle 1. Plates, panels, or barriers inside a muffler that reduce sound. 2. A condition resulting from mysterious vehicle vibrations.
balance tube Short, laterally positioned pipe connecting the exhaust pipes on a dual-exhaust system. Used to equalize gas pressure between the two pipes.
ball joint A flexible joint consisting of a ball used in a socket, mainly in front suspensions because it can accommodate a wide range of angles.
BDC Bottom Dead Center, the lowest point of a piston's travel within the cylinder.
bead 1. The inner lip of a tire that attaches to the wheel. The exterior rubber bead conceals an embedded wire reinforcement. 2. In welding, a narrow half-round line where two pieces of metal have been joined.
bead lock A two-piece system that clamps the tire to the rim, especially helpful when airing down your tires for off-roading.
beater A truck that is rough or dented on the outside but might be mechanically sound. Syn. Bomber.
beefed-up 1. A 4x4 that is stronger than stock. 2. An after-dinner condition on the trail.
beltline 1. Body line running from front to back on a truck's side that visually separates the lower body from the lower edge of the greenhouse, the roof, and window assembly. 2. A measurement that increases as we get older.
bench race To talk about your truck and your driving feats as if they were fish stories.
bezel Trim ring, usually chromed or polished, that surrounds headlights or gauges.
bicycle To ride on either both right- or left-side wheels.
bikini top 1. A soft top that covers only the front seats and leaves the rear uncovered. 2. What many of us like our significant others to wear on the trail.
bellhousing Bell-shaped enclosure for the clutch and flywheel on a manual transmission or the flexplate and torque converter on an automatic transmission.
billet A part machined from a single piece of metal, not a casting.
bleed 1. To remove air in a hydraulic system by pumping out fluid. 2. What hands often do while working on trucks.
blip Quick touch of the throttle to momentarily rev an engine.
blower 1. Supercharger. 2. Ventilation system's motor.
blown engine 1. A seriously damaged engine. 2. A supercharged engine.
blow the doors off To defeat a competitor during a speed contest.
blueprint To rebuild an engine to its OE design specs, machining and checking the weight, size, and fit of each component against a factory blueprint.
bobbed The rear of the truck, SUV, of Jeep has been shortened, usually adjusted for better departure angle.
body roll 1. Tendency of a truck's body and chassis to lean toward the outside of a turn as the result of cornering forces. 2. The flesh that protrudes over our beltlines.
bog 1. Running an engine below its intended operating range by driving in too high of a gear for the speed or load. 2. The mud pit at a mud-bog race.
bogger 1. A vehicle built for mud racing. 2. One who mud-races. 3. (cap.) Type of tire
boiling the balonies Spinning the tires.
bolt-on Aftermarket part or component that can be installed without special modifications or major disassembly.
boneyard 1. Wrecking yard, junkyard, salvage yard. 2. The Back 40 of many 4x4 owner's homes.
boost The increase in intake pressure above atmospheric pressure provided by a supercharger or turbocharger. Boost is measured in psi.
bore 1. The diameter of a cylinder. 1. The act of machining a cylinder to fit larger pistons.
bored-and-stroked Combination of an enlarged cylinder bore and a lengthened piston stroke, resulting in an increase in overall engine displacement and power; rarely boring.
bottom end 1. The crankshaft, connecting rods, and main bearings of an engine. 2. Power at low engine speed.
bottom-out When the truck's suspension is fully compressed and its bumpstops won't allow further suspension travel.
boxed Strengthen a frame by adding a metal plate to an open-channel framerail or crossmember, thereby turning a three-sided framerail into a four-sided rail.
brake fade A loss of braking power, the result of the brakes' friction surface or the brake fluid becoming overheated.
broach to pierce or open, sometimes referring to a splined cut on a gear or flange.
bulletproof An allegedly indestructible truck or component.
bump 1. A horizontal obstacle. 2. To blip the accelerator. 3. To back off an obstacle, then hit it again with momentum.
bumpsteer A situation in which the steering jerks when a truck encounters a bump in the road. Bumpsteer is often caused by improper steering geometry.
bumpstick Camshaft
bumpstop Rubber or urethane block used to limit suspension compression travel.
burnout Deliberate spinning of the rear tires to heat and clean the tires' tread in preparation of maximum acceleration from a standing start. Can also be used to impress onlookers.
butt-scratcher A trail obstacle that scrapes on a truck's rear end.
cam 1. An eccentric device which converts rotating motion to reciprocating movement 2. Camshaft.
camber The tilt of the front tires toward or away from the center of the truck relative to vertical. When the top of the tire leans out the camber is positive; if the tire leans inward, camber is negative.
cam duration Amount of time, expressed in degrees of crankshaft rotation, that a cam holds open the intake or exhaust valves.
cam lift Distance, expressed in thousandths of an inch, at which a cam opens the valves.
candlepower A light brightness rating. Not all manufacturers use the same method to determine candlepower.
caster The fore or aft tilt of the steering axis relative to vertical. Lifting a truck can cause too much negative caster, which results in wandering.
catalytic converter An emissions-control device that routes exhaust gases through an oval-shaped canister filled with palladium and platinum pellets, thereby converting the toxic exhaust gases to water vapor, carbon dioxide, and less-toxic gases. Syn. cat.
CB Citizens band radio. A two-way radio commonly used for communication between trucks on the trail.
center disconnect A four-wheel-drive system that engages the front axles at an inboard location rather than the outboard hubs.
center of gravity The theoretical center of mass in a vehicle. It can change dramatically due to passenger load and cargo.
cherry Clean, in unusually fine shape.
CFM Cubic feet per minute, generally used to measure airflow through a port, intake manifold, or carburetor; a system used to determine carburetor and fuel-injection capacity.
chaindrive A system in which a chain and sprockets drive gears instead of the gears being meshed together.
chick-deflector Repulsively ugly vehicle. Ant. chick magnet
chicken-handle A handle for passengers to grab when the going gets rough; also known by other, unprintable names.
chip A computer's microprocessor, computer. A nick in the paint.
chirp the tires To shift quickly during hard acceleration so that the tires momentarily lose traction.
chunk 1. Slang for the ring-and-pinion gear assembly inside a differential housing. 2. When parts eject from their functional location.
clip A truck's entire front sheetmetal section, including the fenders, hood, and cowl.
coilover A suspension that uses shocks with an integral coil surrounding the shock body, often used with custom-fabricated multilink suspensions because they offer the advantages of easy preload and ride-height adjustments, lots of wheel travel, and accurate spring dampening rates.
collector Device that collects exhaust gases from the exhaust manifold's (or header's) primary tubes and routes them into a single-exhaust pipe.
combustion chamber A cavity within the cylinder head(s), just above the piston(s), where combustion takes place.
compression ratio The ratio of cylinder volume with the piston at BDC to the volume remaining in the cylinder chamber when the piston reaches TDC. The greater the difference, the higher the compression ratio, generally producing more power. If the compression ratio is too high, however, it can cause detonation and an increase in pollutants.
contact patch Portion of a tire tread in contact with the road surface.
Cornbinder Slang for any 4x4 made by InternationalHarvester because the company is known for making farm equipment. Syn. 'Binder.
crank it 1. To turn the steering wheel hard left or right. 2. To start the engine.
crankshaft Shaft with large, U-shaped cranks that are connected to the pistons' connecting rods and transforms the pistons' reciprocal motion to a rotational motion, which powers the drivetrain. Syn. crank.
crawl-ratio The lowest gear ratio in the truck, found by multiplying the First gear ratio of the tranny by the low-range gear ratio of the transfer case by the axle gear ratio.
cross-drilled crank Crankshaft with additional lubrication holes drilled opposite the existing main journal oil feed holes, providing improved high-rpm-bearing lubrication.
curb weight Total weight of a truck with the fuel tank full, the engine oil at its proper level, and the cooling system full, but without a payload or passengers.
CV joint Constant velocity joint, two U-joints in tandem or a Rzeppa joint which allows for increased angularity of driveline components. Commonly found on front driveshafts and front-drive axles.
cylinder head The part of an engine that contains the valvetrain and the combustion chambers and covers the tops of the cylinders and pistons.
deck The surface of the engine block on which the head gasket and cylinder sit.
degreeing a cam Using a dial indicator and a degree wheel to verify that a cam's lift and duration is accurate.
departure angle The maximum angle a truck can descend before hitting the rear bumper or other components located behind the rear tires.
Detroit Locker A popular brand of automatic locking differential.
dial-in 1. To set up a truck's engine, chassis, drivetrain, stereo, or other system so that maximum performance results. 2. To set up a mechanical component for trouble-free operation.
direct ignition system Ignition system that has no distributor; ignition is sent directly from the multiple modulators (coils to the spark plugs).
directional tire Tire with an asymmetrical tread that is designed to produce superior traction when rotating in one direction only.
double-line A type of winch rigging that runs the cable to an anchor point and back to the vehicle, thereby doubling the pulling power.
Double-pumper A four-barrel Holley carburetor with mechanical linkage to open both the primary and secondary barrels and mechanical accelerator pumps in both the primary and secondaries.
drag link Steering link that connects the pitman arm to the steering arm.
droop Any downward suspension travel.
drop the hammer To accelerate rapidly from a stop.
dropped pitman arm An offset arm that lessens the angle between the steering box and drag link.
dualie A truck that has dual rear tires on each side.
dual plane An intake manifold with runners that do not share a common plenum, usually designed for low- to midrange engine performance.
dyno Abbreviation for dynamometer, a machine used to measure engine torque either at the flywheel (engine dyno) or rear tires (chassis dyno).
ECU Electronic Control Unit, computer unit for engine management.
EFI Electronic Fuel Injection; computer-controlled fuel delivery system.
EGR Exhaust Gas Recirculation, an emissions-controlled device that reintroduces burned exhaust gases to an engine's combustion chamber.
electronic ignition Ignition system that uses transistorized circuits instead of breaker points.
E.O. Number Executive Order Number, the number assigned to a part by the California Air Resources Board when it becomes legal to use on emissions-controlled vehicles.
exhaust backpressure Resistance to the free flow of exhaust gases through an exhaust system
exhaust headers Performance exhaust manifold built from equal-length steel tubes that is designed to speed the flow of exhaust gases exiting the cylinder head(s).
exhaust manifold Tubular cast-iron component that routes exhaust gases from the cylinders to the exhaust system.
fairlead A steel guide installed onto a winch mount to help direct the winch cable. Fairleads come in two styles: roller, which uses steel rollers, or Hawse, which features a simple bracket with large radiused edges for the cable to ride against.
fan clutch Thermostatically controlled clutch device that engages or disengages a mechanical radiator cooling fan according to the engine's cooling needs.
flathead An early engine design that located the valves in the block beside the cylinders, rather than the head (overhead valves) as is currently done.
flat spot Momentary decrease in engine power at some point within the powerband.
flat-top 1. A piston without a dish or a dome. 2. A popular '50s haircut.
forced induction Supercharged or turbocharged
four-banger A four-cylinder engine.
four-bolt main A crankshaft's main bearing caps held in place by four bolts.
freewheeling When the front hubs are unlocked and the wheels spin because of momentum rather than power.
fuelie Old slang referring to a fuel-injected engine or vehicle.
fuel injector Electromechanical device that squirts fuel into an engine.
full-floater An axle assembly designed to hold the weight of the vehicle on the axlehousing instead of on the axleshafts; has bearings at both the differential and wheel ends.
gas shock Damper shock absorber with two separate compartments, one containing hydraulic fluid, one containing nitrogen gas. The gas keeps pressure on a flexible, in some cases, moveable separating disc, that, in turn, keeps pressure on the fluid, thereby reducing the fluid's tendency to foam during aggressive driving.
g-force Measurement of the force generated during cornering, acceleration, or deceleration, expressed in units of gravity.
glasspacks Tubular style of muffler that uses fiberglass packing to absorb sound.
gnarly A difficult portion of a trail that may or may not make you nervous. Syn. exceptional.
granny gear An extremely low First gear in a manual transmission. For example, an SM465 has a 6.55:1 First gear ratio.
grenade Catastrophic failure of an expensive part. Engines, transmissions, and axle assemblies can all grenade.
greenhouse Upper portion of a truck's body; the structure above the beltline, including the roof, windows, and pillars. Syn. office.
ground effect Reduced airflow under a truck provided by an air dam and side skirts. Less pressure underneath a truck allows the air passing over its top to push downward, thus creating an improved grip on the road as well as improved top speed and fuel efficiency. Impedes ground clearance in 4x4s.
gumbo Deep, sticky mud.
gun it To deliberately rev an engine.
gusset Triangular metal support used to add strength; is welded in place where two framerails connect or where two tubes of a rollcage are welded together.
GVWR Gross Vehicle Weight Rating, the combined weight of a vehicle and its rated cargo capacity.
halogen light High-output headlight or driving light that has halogen gas inside the bulb. When surrounded by a halogen gas, the bulb's tungsten filament can carry a higher current, thus producing a more brilliant white light.
hammered 1. A truck that's thoroughly destroyed. 2. A truck that has a chopped top or a severely lowered suspension.
handle The nickname you use on the CB.
H.E.I. High-Energy Ignition, a powerful and reliable GM distributor assembly with a self-contained coil.
Heliarc welding A form of tungsten inert gas welding used primarily on aluminum and stainless steel.
Helicoil Stripped thread repair system, consisting of small coil-spring inserts that thread into place on damaged female screw threads.
high-centered When a truck is firmly stuck, usually caught on its frame on an obstacle unable to move.
high-pinion See reverse-rotation.
hi-Po High-performance.
hole shot Beating a competitor at the start of a race; coming off of a dead stop quicker; coming out of the hole quicker.
hook up 1. To gain traction. 2. To gain a date.
hub Wheel mounting surface.
huffer A beltdriven supercharger.
hydraulic'd Past tense only, said of an engine that has been submerged in water and has sucked water into its cylinders through the intake and will no longer rotate because the pistons moving up the cylinders cannot compress the water.
IFS Independent Front Suspension, a type of suspension system that allows the two tires on one axlehousing to move separately from one another.
intake ports Passages within a cylinder head that route air and fuel to the intake valves.
juicebox An automatic transmission.
kick-down Quick downshift on an automatic transmission when the engine is given full throttle.
kicker shocks Shocks mounted in a near horizontal position between the axlehousing and the leaf springs. Kicker shocks are valved with a high rate of compression damping and are intended to reduce axlewrap.
kick-up Section of a frame that is curved up to clear an axlehousing.
ladder bars Longitudinal suspension control arms that connect the axle to the frame, preventing axle wind-up and hop.
lash Amount of clearance between a valve and a rocker arm or between a rocker arm and a lifter or pushrod.
lateral link Tubular suspension rod that positions the axlehousing so that side-to-side movement is minimized during cornering.
LED Light-emitting diode, a small semiconductor that lights up when current is passed through it. Used on some dashboard displays and taillights.
lifted Any 4x4 that is raised either by a suspension or body lift.
lift-block A spacer placed between the axle assembly and the springs to lift a truck inexpensively. These are only safe on rear-axle assemblies.
light it off Start an engine.
limited-slip differential Final-drive system where the two axleshafts are mechanically connected with a series of clutchlike plates to prevent wheelspin on slippery surfaces and to ensure that the engine's power is transmitted equally between the two tires.
line A driver-selected path that gives a truck the best route to climb over an obstacle or through a pathway. Choosing the right line is essential to successful four-wheeling.
locked in To have engaged the manual front hubs into the lock position.
locker A device in either the front or rear differential that sends engine power to both wheels regardless of traction.
lockers front and rear One of the most common truck-owner fibs.
Loctite A product used on fasteners to maintain torque.
long-block Engine assembly consisting of a cylinder block, a crankshaft, a camshaft, bearings, pistons and rings, connecting rods, an oil pump, an oil pan, a timing cover, seals, cylinder heads, and an intake manifold.
loud pedal Accelerator.
low gears Gears that increase the amount of reduction in the transmission, transfer case, or axle. In an axle, they are expressed as the ratio of ring-gear teeth to pinion teeth, so low gears are numerically higher than high gears. (Example: 4.10 gears are lower than 3.55 gears.) Rockcrawlers typically have low gears.
low-lock To have the transfer case in 4-Lo therefore locking out the center differential, if so equipped.
mandrel bend Hydraulic or mechanical tube-bending machine that uses dies and mandrels (forms) to bend tubing in such a manner that the walls don't collapse.
manifold cooking To use a hot intake manifold as a heat source for cooking on the trail. Burritos and cans of beans or chili are favorite manifold delicacies.
MAS Mass Airflow Sensor, a device that measures the amount of airflow into the intake manifold. This information, as well as data from other sensors, is sent to the engine's computer, which calibrates the optimum air (fuel and adjusts the EFI system as required.
meats Tires, particularly large, aggressively treaded ones. Syn. skins, shoes.
MIG welding Metal Inert Gas welding is a wire-feed welding system that uses argon gas as a shielding agent for the weld. Steel, stainless steel, aluminum, and other metals are commonly welded with a MIG welder.
mill 1. Engine 2. Milling machine.
modular wheel Custom or racing wheel with an inner, an outer, and a centersection that are bolted or riveted together.
monochrome Styling inspired by European performance cars where the bumpers, grille, body trim, and door handles are painted the same color as the body.
mountain motor Big-block engine, typically bored and stroked to at least 500 cubic inches.
Mouse motor Chevy small-block V-8 engine, named Mouse because of its small overall physical size, and because, some say, GM executives wanted to scare Chrysler's "elephant" Hemi engine with the new, powerful small-block Chevy.
Multilink Solid-axle suspension design where coil springs are used instead of leaf springs, and the axle is located by longitudinal and lateral suspension control arms, or links.
nail it To apply full throttle.
negative offset When the wheel's mounting surface is outboard of its centerline.
normally aspirated An engine that relies on vacuum through its intake manifold and cylinders to draw in an air-fuel mixture; an engine without a forced-induction supercharger or turbocharger.
NOS 1. New old stock; original equipment, unused parts for vintage trucks, often found in their factory cartons at dealerships. Ant. repro, reproduction. 2. A nitrous oxide injection company. 3. Slang for nitrous.
OEM Original equipment manufacturer. Syn. stock.
off-camber A situation in which the truck is sideways on an incline, increasing the likelihood of a rollover.
oil gallery Small passages within the engine block and cylinder heads through which lubricating oil circulates.
one-off 1. Custom part or component that is fabricated from plans; no other identical copy exists. 2. Wide-production modifications to an existing vehicle, such as a Saleen Explorer.
out to lunch Worthless, a truck that doesn't run well or look right.
oversteer Cornering condition where the rear tires slide toward the outside of the turn.
Panhard rod A transverse link (rod that attaches to the truck's frame at one end and to the axlehousing at the opposite end), providing lateral positioning of the axlehousing relative to the chassis.
paperweight A part that's broken beyond repair can be used as an excellent paperweight.
payload Maximum weight a truck can carry, calculated by subtracting the curb weight of the truck and a 150-pound allowance for each passenger from the gross vehicle weight rating.
peg-leg An open differential. Syn. one-legger.
pickle fork Fork-like tool used to separate suspension components, such as ball joints and tie-rod ends, for repair.
pinion angle The angle of the pinion yoke on an axlehousing in relation to its driveshaft.
pitman arm Steering lever that converts the rotary motion of the steering box to the linear motion of the steering system's centerlink.
plenum Box or cavity at the intake manifold's entrance that stores the air/fuel mix for distribution to the intake runners.
plow Understeer.
port injection Electronic fuel-injection system that injects fuel directly into the cylinder-head ports.
posi Short for Posi-traction, a limited-slip differential used by General Motors. The term is often used generically for any limited-slip device.
positive offset When the wheel's mounting surface is inboard of its centerline.
prerunner An off-road truck that's built to prerun a desert race course so that the driver can study and practice on the course before the race.
progressive-rate springs Suspension springs that become progressively stiffer as they are compressed.
proportioning valve Hydraulic braking valve that varies the braking force at the front or rear wheels, depending on pedal pressure, load, and weight transfer, to reduce or eliminate wheel lockup.
P.T.O. Power take-off, an accessory powered by engine output, usually a winch.
pumpkin The centersection of an axlehousing that contains the differential carrier and gearset. Syn. coconut, third member.
pushrod Thin metal rods that transmit the motion from the camshaft and lifters to the rocker arms, and thus operate the valves on an overhead-valve (OHV) engine.
quad 1. Four-barrel carburetor. 2. A four-wheeled all-terrain vehicle.
quarter-panel Body shop term for the front or rear corner sheetmetal assembly.
radius arms Brackets used by Ford that locate the front axlehousing on coil-spring suspensions. Dodge and Jeep use similar brackets. Syn. trailing or control arms.
rack-and-pinion A steering system that uses a pinion gear at the end of the steering shaft to engage a horizontal-toothed bar, the rack, which is attached to the tie rods and the steering knuckles.
rake When the frontend of a truck sits lower than the rear.
ramp breakover angle The angle formed by lines drawn from the front and rear tires' contact patches and the midpoint of the wheelbase on the chassis; the greater the angle, the less likelihood of high-centering.
Rat Chevy big-block V-8 engines, normally offered in 396ci, 402ci, 427ci, and 454ci sizes. Named because it was a large companion to Chevrolet's small-block Mouse V-8.
rebound After a suspension spring is compressed by a bump, the spring naturally tries to return to its previous length, extending the suspension upward toward its original ride height.
recirculating ball steering Steering assembly that uses a worm gear on the end of the steering shaft to turn a sector gear that is within the steering box and attached to the pitman arm. Ball bearings are used between the worm and sector gears for smooth operation.
redline Absolute maximum engine speed, expressed in rpm, at which an engine can/should be operated; indicated by a red line on the tachometer. Syn. rev limit.
repro Aftermarket reproduction parts, manufactured to appear, fit, and function as originals. Not the same as OE or N.O.S., which are both factory-issued parts.
restify To build a truck that is basically restored but has been updated with modern convenience and performance enhancements.
retrofit Installing new parts or systems on an older truck for the purpose of upgrading, such as retrofitting a modern fuel-injection system in place of the original carburetor.
rev limiter An adjustable electronic device that restricts engine rpm to a predetermined limit so engine damage does not occur.
reverse-rotation Refers to an axle design where the pinion is positioned above the axle centerline.
ring-and-pinion Gearset that drives the wheels; the pinion is a gear attached to the rear of the driveshaft, and the ring gear is part of the differential that turns the axles.
rock magnet A low-hanging component of a 4x4, such as a ladder bar, that seems to catch on every obstacle.
rock massaging Body damage caused by rocks and other obstacles on the trail.
rocker arm Pivoting valvetrain levers. One end of an engine's rocker arms are moved by the pushrods/lifters and the opposite end's open intake or exhaust valves.
rocker panel The sheetmetal section of a truck's body located below the doors and between the front and rear wheel openings.
Roots supercharger Positive-displacement, beltdriven supercharger; originally designed in 1859 by Francis Roots for use as a water pump.
RTI Ramp travel index, a measurement of suspension flexibility and articulation that's calculated by dividing the distance the hub's centerline travels up a (usually 20-degree) ramp by the vehicle's wheelbase in inches, multiplied by 1,000.
sanitary Well designed, engineered, and constructed; cleanly built; superior mechanical workmanship. Syn. sano.
semi-floater An axle assembly that carries the weight of the vehicle on the axleshafts. These are typically weaker than full-floaters.
serpentine belt Engine accessory drivebelt that is long and follows a snaking path while driving the alternator, water pump, A/C unit, and power-steering pulleys.
shackle Connector between the rear of a leaf-spring pack and the frame; allows the spring to lengthen as the suspension is compressed.
shift kit Package of high-performance components for an automatic transmission that firms the shifts, alters the shift points, and improves overall performance.
shiny-side down When a truck rolls over. Syn. rubber-side up.
short-block An engine block that has a complete bottom end, including the crankshaft, rods, pistons, and camshaft, but without the cylinder heads, intake and exhaust manifolds, water pump, and other accessories.
sidehill A portion of a trail that leads across a steep hill instead of up or down. See off-camber.
single-plane manifold Intake manifold with a single plenum feeding all of the engine's intake runners.
skin Body sheetmetal.
skins Tires.
slickrock A type of sandstone dominant in Moab, Utah. Slickrock actually isn't slick and provides excellent traction.
slushbox An automatic transmission. Syn. juicebox.
small-block A V-8 engine typically having 400 or less cubic inches of displacement.
snatch-block A pulley device used in assisting with getting unstuck; it doubles as a winch cable's pulling power.
snatch strap A thick nylon strap used to pull out stuck vehicles. Syn. tow strap, yank strap.
spool out To pull the winch cable off the drum after releasing the brake.
spotter A codriver who helps guide the driver over obstacles, often using hand signals.
spring rate The force required to deflect a spring 1 inch, expressed in pounds per inch of spring compression or deflection. The higher the per-inch spring rate, the stiffer the spring.
spun bearing A bearing that is either worn or frozen and has rotated in its retainer. In an engine, this causes the bearing to block off its oil passage and results in major damage.
stair-step An obstacle that contains one or more ledges that must be climbed in succession. Stair steps are common on trails that follow washes or creek beds.
stand on it Full-throttle acceleration.
swamped To drown the engine; to drown the entire truck.
synthetic oil Manmade lubricants; they generally have a greater capacity to lubricate and resist heat than standard mineral oil.
tachometer Device used to measure and display engine speed, expressed in revolutions per minute. Syn. tach.
tack welds Series of small welds, spaced approximately 1 inch apart, which are used to hold together two pieces of metal until the final welding can be performed.
taco'd Axlehousings, frames, or other components that have been severely bent, usually from jumping the truck.
tail gunner The last vehicle/driver on a trail ride. The tail gunner is responsible for making sure everyone completes the trail.
tall gears The opposite of low gears, they are represented in ratios that are numerically lower than "low" gears; e.g., 3.08s are taller than 4.10s.
TBI Throttle-body fuel injection.
threshold braking Applying as much pressure to the brake pedal as possible without going to wheel lockup.
throwout bearing On a clutch assembly, a shaft-mounted bearing that is moved from pressure on the clutch pedal and disengages the clutch disc from the engine.
T-case Transfer case.
tie rod Steering linkage between the pitman or idler arm and a steering arm that moves the steering knuckles.
TIG welding Tungsten Inert Gas welding, also referred to as heliarc welding, usually used for joining aluminum and stainless steel.
timing chain/gears Chain or gears that transmit rotation from the crankshaft to the camshaft.
toe-in, toe-out Inclination of a pair of front wheels slightly inward or outward as viewed from the truck's front.
torque converter Fluid coupling between the engine and the automatic transmission. The engine powers a fan-shaped impeller inside the torque converter, which splashes oil onto a turbine (another fan-shaped device), and the turbine transmits its power to the transmission's gearbox.
torsion bar Suspension spring that looks like a long metal rod. One end is attached to the truck's frame, and the other end is attached to the suspension's A-arm. When the A-arm moves, the torsion bar is twisted and then springs back to its original shape, thus its springing action.
TPI Tuned-port fuel injection.
trail boss The leader of a trail ride.
trailer queen A vehicle that's built primarily for show and is trailered to events.
TTB Twin-Traction Beam, a type of Ford front suspension that utilizes an axle assembly with pivot points, allowing the tires to move independently.
tunnel ram Intake manifold with a large plenum and long, straight runners, used for high-rpm engines.
turned turtle A truck that's rolled upside down.
two-bolt main Engine block with its main crankshaft caps held in place by two bolts.
two-wheeling When tires lift off the ground during a tricky maneuver. Syn. bicycling.
U-bolt U-shaped bolt commonly used to attach an axlehousing to a leaf-spring pack.
U-joint Mechanical joint that can transmit rotary motion while swiveling. Used at both ends of a driveshaft to transmit power from the transfer case to the differential.
understeer Cornering condition where a truck's front tires lose grip before the rear tires, causing the front end to slide or push toward the outside of the corner.
unglued 1. Damaged or destroyed; a blown-up engine has become unglued. 2. The codriver's mental state following a rollover.
vacuum advance Device that advances or retards ignition timing according to the degree of engine vacuum. At low engine speed, there is plenty of engine vacuum, so the ignition is advanced; at wide-open throttle, there is little vacuum, so the ignition remains at its original timing advance.
vacuum secondaries Secondary carburetor barrels that are pulled open by engine vacuum.
valve lift Circular, stemmed device used to control the airflow in and out of an engine; operated by the camshaft/pushrods/rocker arms.
valvetrain The valve lifters, pushrods, rocker arms, and valve springs.
vaporlock Condition where fuel boils within the fuel line or carburetor, causing bubbles to form that impede the fuel flow or cause excessive fuel to flood the carburetor.
variable-ratio steering Power-steering box that varies the steering ratio. At low speeds, the steering response is quicker for maneuverability; at high speeds, the steering ratio is reduced for stability.
ventilate the block To throw a connecting rod through the side of an engine block due to component failure or excessive revs.
venturi Carburetor barrel or throat with a slightly narrowed or hourglass shape to its interior. The small, narrowed area speeds up airflow and helps pull the fuel past the carburetor jets and into the air stream.
VIN Vehicle identification number, a serial number that identifies a vehicle.
wail To perform at peak power or efficiency.
wheel adapter Metal plate with wheel studs that allows a wheel with one bolt pattern to be used on a truck with a dissimilar bolt pattern.
wheelbase Distance from the center of a truck's front wheel to the center of the rear wheel on the same side.
wheel travel The total distance a wheel can move up and down; affected by suspension travel and wheelwell clearance. More wheel travel means a more flexible suspension and more potential traction.
white-knuckle An obstacle that is scary enough to make the driver grip the steering wheel extremely tight.
windage tray An internal engine shield, mounted close to the crankshaft and intended to deflect oil away from the crank as it rotates.
wiring harness Major part of a truck's electrical wiring system; a group of wires bundled together.
WOT Wide Open Throttle.
wrist pin Hollow metal tubular pin that attaches the piston to the connecting rod.
zerk fitting Nipplelike fitting on suspension and chassis parts and on U-joints, through which lubricant is pumped under pressure to lubricate the components' internals.