Driver Knowledge Tests

What do you need in a vehicle for off-road driving?

If you’re interested in getting into some off-road driving, there are some features that are important to have on your vehicle.

Four-wheel drive

You’ll soon get stuck if you don’t have four-wheel drive, and it’s preferable if your four-wheel-drive system has a diff-lock function, otherwise it’s basically a two-wheel-drive (one at the front and one at the back) if you get beached. A lockable diff gives you three wheels providing power. Four-wheel-drive is a misnomer: the differentials at the front and rear mean that if you lift one wheel at the front and back, they will both spin while the other two have no rotational force at all.

Off-road tyres

Road tyres will fill up with mud quickly and you’ll have no grip. Off-road tyres are designed to shed the mud quickly. They have wider, deeper grooves that bite into mud.

You don’t have to go this extreme, but it will get you places that other vehicles have no chance of reaching

Off-road suspension

If you’re in the serious rough stuff, your suspension will need to have sufficient height so that you don’t get beached on minor humps, and you don’t bottom out and damage the underside of your vehicle.

This 4wd is at risk of becoming beached with its long wheelbase and low running boards. This determines the ramp breakover angle
This has plenty of ground clearance but looks like it’s all show

Suspension articulation is important. This is the ability for the suspension to keep as many wheels on the ground as possible at any one time.

How to keep four wheels on the ground even in big ruts. Note that the differential between the rear wheels is usually the lowest point for ground clearance – you can’t change this much without going to much bigger wheels

Tools and emergency gear

You will have breakages. It is inevitable. A good tool kit and some common spares is essential.

Flat tyre means you’re going to get dirty changing it

You will get stuck occasionally so a good, strong towing strop is important.

Keep a strong D shackle rated to tow the weight of your vehicle. Always tow using the designated towing points.

D shackle: the safe working load will be stamped onto the body of the shackle

A winch is optional, but handy if you’re mostly adventuring on your own. You can attach it to something solid, like a rock or tree, and have it give you extra pulling force to get unstuck.

Running out the winch when you’re stuck is your passenger’s job

Snorkel

For river crossings, you’ll need a snorkel if it’s deeper than the air intake on the engine.

Bull bars

If you’re bashing through the bush, you can save your paintwork with some bull bars and other protective tubing.

Buy the size suitable for your requirements

Hardcore off-road vehicles tend to have a short wheelbase with the wheels at each corner as this gives the best approach and departure angles (the angle of slope you can ascend from a flat surface without the front bumper hitting the slope and the angle of slope you can leave without the back bumper hitting the slope.

The front wheels on this vehicle are partially ahead of the front of the vehicle, meaning it can cope with extreme angles
Part of the success of the Land Rover is that it has a wheel at each corner, giving it excellent approach and departure performance.

Darren is an expert on driving and transport, and is a member of the Institute of Advanced Motorists

Posted in Advice