Four-wheel drive tips for intermediate off-roading

Last year we took a look at the basics of four-wheel driving with our Beginners Guide to Off-roading.

The three-part series served as a how-to guide for those new to the world of four-wheel driving, imparting the fundamental skills required to get yourself off the beaten track – and back again!

This time round we’ll build on those skills by focussing on the specific challenges novice off-roaders can struggle with: steep terrain, water fording and sand driving.

As is the case with all advice offered on this site, we stress that the following material is general of nature and may not apply to your specific circumstances. We recommend undertaking an off-road driver training course with a reputable four-wheel drive club or training facility to further your experience.

But it’s also an exciting activity that, done right, is rather rewarding. Climbing or descending a precipitous grade is also a pretty important staple skill, especially if you plan on getting anywhere interesting.

Ruts, alternating surfaces and other hazards – including protruding rocks and tree roots – are worth making a note of, as is the correct approach. Remember: never drive across a steep hill or ruts on an angle as this will significantly increase your risk of a roll-over! If you have to stop on a steep incline for any reason, set the parking brake securely, select Park (or leave manuals in first gear) and chock the wheels.

Make sure you have your recovery gear at the ready as it may be difficult to access these items should you become stuck half-way up. If you have a winch, be sure it’s in working order before setting off, and make sure any connections you needed are made prior to setting off. Finally, be sure to wear your seatbelt.

Your next objective is to maintain motive traction. Encountering wheel spin half way up a hill is a sure-fire way to lose momentum, which could see you sliding back down the way you came. It’s a great idea to lower your tyre pressure a little when climbing steep grades, assuming you haven’t done so already.

Select low-range four-wheel drive and select a low gear (first or second), and climb the hill with a steady throttle to maintain momentum – do not stop. Try to complete the ascent in one smooth attempt. Be sure to stick to your line, and if necessary, get a friend to guide you up via two-way radio to avoid becoming stuck in a rut – or hitting an obstacle.

If you don’t make it up, or stall your vehicle mid-way, be sure to know how to recover – an uncontrolled descent in reverse is a recipe for disaster!

Make sure your vehicle remains in gear (do not descend in neutral or with the clutch depressed), and avoid using the brake – locking the wheels on a steep descent means you lose the ability to steer! Use only light brake pressure where necessary and always engage reverse gear while remaining in low-range four-wheel drive. This will give you ample engine braking to make the descent safely, gravity will do the rest.

Again, if you have a guide, have them direct you down the hill, but be sure they remain to the side of the track and not directly behind the vehicle. And if you’re travelling in convoy, be sure to leave plenty of space between yourself and the car ahead of you.

Once you’re down safely and ready for another attempt, try to figure out where it went wrong the first time. It may be that you need to find a different line, lower your tyre pressure some more, or engage your differential locks (where fitted)… or find another way around.

Technique wise it’s actually quite similar to reversing down the hill we mentioned a moment ago. Except this time you can see where you’re going.

As with heading uphill, heading downhill is all about motive traction. As with most off-road obstacles, a steep incline is one best assessed before you begin. If necessary, hop out of the cabin to get a better view, and consider walking the climb first to understand potential risks. Ruts, alternating surfaces and other hazards – including protruding rocks and tree roots – are as much of an issue heading downhill as they are heading up. If you need to, spend some time constructing a smoother path by moving rocks and tree branches to help you out.

Get as much traction as you can. Drop your tyre pressure, and select low-range and a low gear ratio (we recommend first or second depending on the severity of the grade). You can opt to use hill descent control if fitted; however, this does use the brakes, which in turn could mean losing motive traction.

Travel slowly, and use your brakes lightly. Braking hard could lead to a lack of control and a lack of steering! In manual vehicles, it could also stall the engine, resulting in a loss of engine braking (and perhaps control). Remember, just because your wheels have stopped moving doesn’t mean your vehicle will, especially on loose or slippery surfaces.

Finally, as is the case when travelling up hill, remember to never drive across a steep hill or ruts on an angle as this will significantly increase your risk of a roll-over. If you have to stop on a steep decline for any reason, remember to set the parking brake securely, select Park (or leave manuals in reverse gear) and chock the wheels.

Water fording
As with ascending and descending hills, water fording (or water crossing) is a challenge with near infinite variables. The depth of the water is an obvious consideration, as is the rate at which the current is flowing (both could cause the vehicle to float), and the underwater surface (mud, rock, sand, etc.) you’ll need for traction.

It’s also very important to know the wading depth of your vehicle. Some four-wheel drives have very limited water fording abilities while others are substantial. The reasons for this vary, though usually it relates to the position of the engine’s air intake. Remember: never exceed the manufacturer’s recommended wading depth as water and internal combustion engines don’t mix!

We also need to stress that a typical water crossing is a very different prospect to driving through flood water, and can’t emphasise strongly enough how dangerous this can be.

It’s a great idea to attach your recovery strap before heading in. There’s nothing more unpleasant than trying to connect your snatch strap underwater. Make sure, however, these can’t come lose and be dragged under your wheels.

For extended (or multiple) deeper crossings, consider coating your engine bay’s electrical connections with a thin film of water repellent; and as counter-intuitive as it may sound, leave your windows down to act as an emergency exit, just in case the worst happens. We also recommend slackening the fan belt of engines fitted with a direct-drive cooling fan (just don’t forget to tighten it once across), and make sure you’ve set an appropriate tyre pressure for the terrain beneath the water.

Always make sure it’s safe to cross before driving in. If you’re in the tropics, check for crocodiles, then hop out of the cabin and assess the depth and current. Allow a hot engine, transmission or differential to cool before you head in, and avoid deep holes or submerged obstacles (if you can’t see these from the bank it may be worth walking across first).

Select the right gear ratio for the crossing – you want to maintain a steady pace. Enter the water slowly, and once the front wheels are in, accelerate gently so as to create a bow wave in front of the vehicle (not only will this help prevent excessive water from entering the engine bay but it also makes an easier ‘path’ for the vehicle to follow). Do not change gears mid-crossing, and follow your line until you reach the other side.

When you’ve made it to the other side, stop for a moment to allow water to drain from your vehicle – but do this in a place that won’t make the climb out more slippery for others – and remember to dry your brakes by cycling the pedal a couple of times.

If you don’t make it, don’t panic. Leave the engine running to prevent water ingress through the exhaust. It’s expected that as the stranded driver you’ll get the wettest, so jump out, get wet and connect your recovery gear for rescue.

Sand Driving
Like much of the terrain you’ll encounter when four-wheel driving, sand can vary. Depending on the size of the grain, how wet or dry it is, and even the time of day, sand can change from compact and predictable to soft and unstable.

The techniques below, therefore, are general of nature, but should help you through anywhere soft sand is present.

As was the case with tackling steep terrain (above), we emphasise that you should avoid driving diagonally across a grade – this also applies to sand dunes – as this can result in a vehicle roll-over. Otherwise, the fundamentals to sand driving are essentially tyre pressure, momentum and a little common sense.

From here it’s a matter of maintaining momentum. Floating across the surface requires less effort from tyres and engine alike. It’s important to remember, however, that excessive speed is not recommended on lower tyre pressure, nor are sudden changes of direction.

Keep a look-out for vehicles approaching. Wear a sand flag to be seen over dunes, and when cresting a dune remember to lift of the throttle to prevent the vehicle from ‘launching’ over the top – you never know how steep the other side may be.

Of course there’s no perfect sand, and soft spots (which can be very hard to see in bright sunlight), or driver error, can see you become bogged. If you get stuck, don’t spin your wheels – this will result in digging yourself deeper in to the sand. Instead, hop out of the cabin and assess the best plan of attack. Use gravity wherever possible to make it easier on yourself (and your vehicle), and try reducing your tyre pressure even further to help gain traction.

Reversing out is generally a good idea. The sand you’ve just travelled across is better compacted than what lies ahead! If this doesn’t work, try digging a trench for your wheels to follow, using a traction aid (like Max Trax) or have a companion tow you out.

Finally, if you’re driving on the beach, don’t get too close to the surf. Not only will the salt water damage your vehicle over time, but the sand is unpredictable, and can easily swallow a four-wheel drive, especially when the tide is changing.

Gear essentials
We see a lot of four-wheel drivers carrying everything on their trips – including the kitchen sink. But there are a few essentials we recommend carrying with you, or having fitted, that may help get you out of bother.

>> Suitable recovery points (factory tow hooks are not always strong enough)
>> Heavy-duty D-shackles
>> Snatch strap (with tree protector and/or bridle)
>> Max Trax
>> Air compressor
>> Tyre deflator
>> Tyre pressure gauge
>> Torch
>> Long-handled shovel
>> Sand flag (for sand driving)
>> UHF radio
>> Satellite phone (optional, may be hired for longer trips)