Off-road driving challenges the traveller in a completely new way, and driving techniques vary with the ability and weight of the vehicle, as well as with the driver. Some vehicles have greater capabilities than many drivers can handle and there may often be more than one way of solving a particular problem.

Before you start

Before driving off-road, look under your vehicle and note the position of its lowest points: exhaust pipes, towing plates, springs, axles, differentials, transfer box and gearbox. These may be lower than expected, on some vehicles they are not in line, and the differentials are usually off-centre. Remember their clearance and position when traversing obstacles. Position the number plates and lights above bumper level, to avoid damage from the terrain. Ensure there are strong towing eyes.

Rules of the road

Alert but restrained driving is essential. A light foot, and low gears in four-wheel drive, will usually get vehicles through difficult situations. Sometimes sheer speed may be better, but if you lose control at speed, you could suffer damage or injury. Careful driving saves time, money and effort. Careless driving breaks chassis, springs, half-shafts and clutches. And remember: never hook your thumbs around the steering wheel. A sudden twist of the wheel, when a front wheel hits a stone or rut, can easily break them.

Always travel at a sensible speed, watching for problems ahead. If you are on a track where it is possible that another vehicle may come the other way, have a passenger keep a lookout further ahead, while you concentrate on negotiating difficulties. Travel only at speeds that allow you to stop easily within the limit of clear vision. Travel slowly to the brows of humps or sharp bends; there may be large boulders, holes, or steep drops beyond them. Make use of the rhythm of the suspension, touch the brakes lightly as you approach the crest of a hump and release them as you pass over it; this stops the vehicle from flying.

When you come to a sharp dip, ditch, or rut, cross it at an angle, so that only one wheel at a time drops into it. Steer the wheels towards and over the terrain's high points to maintain maximum ground clearance. Always change to a lower gear before you reach problems, to remain in control. With permanent four-wheel drive systems, remember to engage lock before entering difficult situations.

Apart from soft sand and snow, most situations where four-wheel drive is needed also require low-range for better traction, torque and control. They will normally also require you to stop and inspect the route on foot first, so you can engage low- range before starting off again.

On soft sand it is useful to be able to engage low-range on the move. On some vehicles, this requires practice at double-declutching. For most situations, first gear low-range is too low and you might spin the wheels; use second or third gear, except over large rocks.

Watch the ground

Keep an eye on previous vehicle tracks, they will indicate trouble spots that you might be able to avoid.

If you cannot see the route or obstacles clearly from the driving seat, get a passenger to stand in a safe place where he or she can see the problem clearly and direct you. Arrange a clear system of hand signals with the person beforehand, since vocal directions can be drowned by engine noise. Only delegate one person to do this: more than one becomes confusing.

On slopes

Do not drive on the outside edge of tracks with a steep drop, they may be undermined by water and collapse under the weight.

Do not tackle steep hills diagonally, if you lose traction and slip sideways, you may turn over. Only cross slopes if it is absolutely necessary. If you must do so, take the least possible angle and make any turns quickly.

Before descending any steep incline, check that the vehicle is still in gear in both the main gearbox and the transfer box. When descending steep, loose or muddy inclines, there is a high chance of skidding. Use second gear, low-range engine- braking in four-wheel drive with any centre differential locked in. With automatic transmission, use first gear plus left-foot braking, and use the accelerator to keep the wheels moving. Depress the accelerator gently, when correcting a skid.

If you lose traction going uphill, swing the steering wheel from side to side - you may get a fresh bite and make the top. If you fail going up a steep hill, change quickly into reverse, make sure you are in four-wheel drive with the centre differential locked if you have one and use the engine as a brake to back down the same way you came up. Do not try to turn round or go down on the brakes.

Be prepared to stop quickly on the top of a steep hill, the way down the other side may be at a different angle.

Surface effects

All braking on loose surfaces or corrugations should be cadence braking, i.e. several short pumps, unless you have ABS brakes. In really loose situations, turn ABS systems off.

If you have been in four-wheel drive on a hard surface, when you change back into two-wheel drive (or, for permanent four-wheel drive systems, you unlock the centre differential lock) you might find this change and the steering difficult, due to wind- up between the axles. This scrubs tyres and damages the drive train. If you are lightly loaded, free it by driving backwards while swinging the steering wheel from side to side. If you are heavily loaded, free it by jacking up one front wheel clear of the ground; keep clear of the wheel, which may spin violently.

On loose surfaces, don't change gear going up or downhill, you'll lose traction.

Overcoming obstacles

If you cannot avoid a rock, drive over it square on with a tyre, which is more resilient and more easily repaired than your chassis. To traverse large boulders, use first gear low-range and crawl over, using the engine for both drive and braking. Avoid slipping the clutch or touching the brakes.

You may have to build up a route, putting stones or sand ladders across drainage ditches, or weak bridges, chipping away high corners, or levering aside large boulders. If you have to rebuild a track or fill in a hole completely, do so from above, rolling boulders down instead of wasting energy lifting them from below. Where possible, bind them together by mixing with tree branches or bushes.

Pistes and dirt tracks

Except on soft sand, use two-wheel drive: this gives more positive steering and avoids transmission wind-up. Tyres should be at correct pressures.

Watch out for stones thrown up by other vehicles, never overtake when you cannot see through the dust of the vehicle ahead, and use the horn to warn vehicles you are about to overtake. Culverts do not always extend to the full width of dirt roads, watch out for these when overtaking.

Avoid driving at night: potholes, culverts, broken-down trucks, bullock carts and people are difficult to see; many trucks drive at speed without lights and then blind you with full beam when spotting you. Many countries have unlit chains and logs across roads at night, as checkpoints.

Bull dust

Bull dust hangs in the air, obscuring vision. When travelling downwind you have to stop often to let it clear. If you cannot see to overtake, drop back and wait until the piste changes direction so that the wind blows the dust to one side, providing clear vision.

Corrugations

Corrugations give an effect similar to sitting on a pneumatic drill to both vehicles and their occupants. Corrugations also find weaknesses in the suspension and electrical cable insulation: coil springs dislodge, leaf springs break, shock absorbers fail and electrical shorts cause vehicle fires; a battery isolator is essential.

Avoid travelling beside the corrugations: other vehicles will have tried that before and given up - hence the corrugations. Take it steady and be patient.

Except on sand, long-wheelbase vehicles should not use four-wheel drive on corrugations. The rear axle supports most of the load and has the strongest differential; in four-wheel drive, snatch loads could damage the front differential or half-shafts.

Light vehicles may 'smooth out' the bumps by achieving enough speed to skim over the tops. Going fast over corrugations increases tyre temperatures, causing punctures. Softly sprung vehicles can go faster more smoothly, but often blow tyres and turn over. With minimal area of tyre in contact with the ground at any time, braking should be light cadence, and any turns of the steering wheel should be gentle. Short-wheelbase vehicles often become unstable on corrugations.

Radial tyres give a more comfortable ride. But do not lower the tyre pressures: there are usually sharp stones, and soft tyres run hotter.

Ruts and gullies

Where possible, you should straddle ruts with your wheels on either side. Larger ridges or ditches should be crossed at an angle in four-wheel drive. Ditches can be bridged or ramps built up to ridges with supported sand ladders. Ditches can be filled in with logs or stones; clear them again afterwards to avoid local flooding.

There will be points where the lowest parts under your vehicle may ground. Where these occur, try to remove the problem, or fill in the ruts with stones or brushwood: continually grounding differentials causes drain plugs that are not recessed to come undone and drop out.

Ruts negate steering. Even in four-wheel drive, turning the steering wheel has little effect on the vehicle's direction of travel. Check regularly out of the driver's window to ensure that the front wheels point straight ahead: otherwise, if they find some traction or the side of the rut is broken away, the vehicle may suddenly veer off the track.

If you are stuck in a rut on firm ground, try rocking out by quickly shifting from first to reverse gear. Do not try this on sand or mud, you will sink in deeper. If this fails, jack up the offending wheel and fill in the rut with stones or logs. A high-lift jack makes this easier and can, with care, also be used to shunt the vehicle sideways out of the rut.

Deserts and sand

Deserts are not all impassable sand dunes. Even large dunes are passable, and most deserts have larger areas of stone than of sand.

Most deserts freeze overnight in winter, making the surface crust firmer. Even if not frozen, there will be dew in the surface crust, making it firmest around dawn. This is the time to tackle dunes and the softest sections. Avoid travelling in the late afternoon, when low sun makes it difficult to spot sudden changes in dune strata (many accidents occur as vehicles fly off the end of steep drops).

Watch out for any changes in surface colour. If the surface you are driving on is firm and the surface colour remains the same, then the going is likely to be the same. If the colour changes, you should be prepared for possible softer sand. Moving sand dunes and dry riverbeds produce the most difficult soft sand.

Do not travel in other vehicles' tracks: the crust has already been broken and your vehicle's chassis will be that much lower and therefore nearer to sticking, to start with. Keeping your eye on other people's tracks will warn you of soft sections, but do not follow them for navigation, they may be 50 years old.

Never use aggressive-tread tyres on sand. Only a small percentage of desert sand is really soft; use tyres at normal pressures so that you can travel at comfortable speeds on the firm sections and make full use of speed where you have room on soft sections. Only lower tyre pressures where necessary.

In general, flat sand with pebbles or grass on its surface, or obvious windblown corrugations, will support a vehicle. If in doubt, get out and walk the section first. Stamp your feet, if you get a firm footprint then it should support your vehicle; but if you get a vague oval, then it is too soft.

If the soft section is short, you can make a track with sand ladders. Long sections require low tyre pressures and low-range four-wheel drive. Bedford trucks will not handle soft sand without the assistance of perforated plates and lots of human pushing power.

The key to soft sand is flotation and steady momentum; any abrupt changes in speed or direction can break through the firmer surface crust, putting the wheels into the softer sand below. Use as high a gear as is possible to avoid wheelspin. Speed up as you approach a soft section and try to maintain an even speed and a straight line across it. If you find yourself sticking, press down gently on the accelerator. If you have to change down, do so smoothly.

Dry river beds can be very soft and difficult to get out of. Drift sand will always be soft. If you wish to stop voluntarily on soft sand, find a place on top of a rise, preferably pointing downhill and roll to a stop without using the brakes and breaking the crust.

Most vehicles have too much weight on the rear wheels when loaded. These wheels often break through and dig in, leaving the front wheels spinning uselessly on the surface. A couple of passengers sitting on the bonnet can help for short bad sections; but you must not overload the front continuously or you will damage the front axle.

On firm sand, two-wheel drive (or with modern Land Rovers, the centre differential locked-out) gives more positive steering, avoids transmission wind-up and allows higher speeds.

Sand dunes require high-flotation sand tyres. You need speed to get up a dune, but you must be able to stop on top, as there may be a steep drop on the other side. Dunes are best climbed where the angle is least, so known routes, in opposing directions, are often some distance apart to make use of the easiest angles.

When descending steep dunes, use second gear low-range and drive straight down, applying some accelerator to control any slipping and retain steering control. If the vehicle noses in, use third gear low-range with your left foot on the brake and enough accelerator to keep the wheels moving.

The bottom of the well between dunes and the leeward faces of dunes have the softest sand.

If you have to sit out a sandstorm, turn the rear of the vehicle to face the wind and cover all windows, to prevent them becoming etched by sand.

Getting unstuck in sand

Once you are stuck in sand, do not spin the wheels or try to rock out: you will sink deeper and may damage the transmission. First off-load the passengers and, with them pushing, try to reverse out in low-range. The torque on the propeller shafts tends to tilt the front and rear axles in opposite directions relative to the chassis. So, if you have not dug in too deep, when you engage reverse, you tend to tilt the axles in the opposite direction to the direction involved when you got stuck, thus getting traction on the wheels that lost it before. If you stopped soon enough in the first instance, then this technique will get you out. If it does not, then the only answer is to start digging and use sand ladders.

It is tempting to do only half of the digging required, but this usually fails and you finish up working twice as hard in the end. Self-recovery with a winch does not work well either. Sand deserts do not abound with trees, and burying the spare wheel or several stakes deep enough to winch you out is just as hard as digging out the vehicle. Another vehicle on firm ground with a winch or tow rope can help, but you must dig out the stuck vehicle first.

Reconnoitre the area and decide whether the vehicle must come out forwards or backwards. Dig the sand clear of all points that are touching it. Long-handled shovels are required to get under the differentials: folding tools are useless. Dig the wheels clear and then dig a sloping ramp from all wheels to the surface, in the intended direction of travel.

Lay down sand ladders in the ramps - rear wheels only, if things are not bad, all four wheels if things are bad. Push the ends of the ladders under the wheels as far as possible, so that they do not shoot out. A high-lift jack helps here. Mark their position in the sand with upright shovels, because they often disappear when used and can be hard to find later. Then, with only the driver in the vehicle, and all passengers pushing, the vehicle should come out using low-range four- wheel drive.

Very fit passengers can dig up the sand ladders quickly and keep placing them under the wheels of the moving vehicle. Sometimes, if a ladder is not properly under a rear wheel when a vehicle first mounts it, it can tip up and damage a body panel or exhaust pipe; so an agile person has to keep a foot on the free end to keep it down. (Remember to move very quickly once the ladder settles, or you'll get run over.) Some sand ladder designs are articulated in the centre, or sectional and tied together, to correct this problem.

Do not tie the ladders to the rear of the vehicle, in the hope of towing them: they may cause you to bog down again. With a large convoy, a ramp of several ladders can be laid down on bad sections.

Driving the vehicle out backwards is usually the shortest way to reach firm ground, but you will still have to get across or around the bad section. Once out, the driver should not stop until he reaches firm ground. The passengers may then have a long, hot walk, carrying sand ladders and shovels, so they should also carry bottles of drinking water.

Vehicles of one tonne or under need only carry sand ladders that are just long enough to fit comfortably between the wheelbase. A single vehicle should carry four ladders; but vehicles in convoy require only two each, as they can help each other. Heavier vehicles require perforated steel or aluminium alloy plate.

Sand ladders and perforated plates bend in use. You can flatten them out again by laying them on hard ground, with the ends on the ground and the bend in the air, and driving over them.

Beaches

Where a beach is the only route, wait for low tide. Beaches are usually firm enough for vehicles between the high tide mark and a line four metres from the sea. In the sea itself there is likely to be an undertow. Beware of the incoming tide, which is often faster than you envisaged and can cut off your exit. Where there are large puddles or streaming water on a sea beach, beware of quicksand.

Salt flats

These behave like quicksand. You sink quickly and if you cannot be towed out quickly, it can be permanent! In areas known for salt flats (sebkhas or chotts), stick to the track, and convoy with other four-wheel drive vehicles. If you hit a salt flat, try to drive back to firm ground in a wide arc. Do not stop or try to reverse out.

Mud

Mud problems are found not only off-road but on main pistes after rain. Many routes immediately south of the Sahara and in South-East Asia become almost impassably muddy for months during their wet seasons.

If mud is heavy with clay, even ultra-aggressive tread tyres clog up. The answer is normal tyres fitted with heavy-duty snow chains.

Winches are useful among trees, but unless you are operating regularly in these conditions the extra weight and cost of these plus ground anchors are rarely worth it. More important is to adapt your vehicle to accept a high-lift jack without it slipping. Fit small sections of angle iron or tube longitudinally to front bumpers and rear chassis, or longer pieces transversely, with suitable notches cut out, to stop jacks slipping. Adaptors are available for fitting high-lift jacks to late-model Land Rover jacking sockets and Toyota Land Cruiser bumpers.

Choose the firmest ground, avoid boulders and tree roots. If necessary engineer a route, dig channels to drain away water, and dig away high points that could be awkward to climb or may cause the vehicle to lean or slip sideways. If the track slopes sideways over a drop, level it out. If the area freezes overnight, or the water is fed by glacier meltwater, then the route will be easier at dawn.

The key to getting through mud is momentum in four-wheel drive, using as high a gear as possible: but there may be unseen problems beneath it. If there are existing tracks or ruts that are not deep enough to ground your transmission, then use them. Otherwise, slog through, avoiding sudden changes in speed or direction.

If you get 'high centred', either jack up one side of the vehicle and build up the ground under the wheels, or shunt the vehicle to one side using a high-lift jack. If you have lost traction, but the vehicle chassis is not grounded, then locked-up drum brakes on wheels that have them, 'heeling and toeing' or left-foot braking if you have automatic transmission, are alternatives, to stop wheels spinning and divert traction to wheels that have grip.

When seriously stuck, digging out is heavy work and leaves the vehicle with a rise to climb. Jack up the vehicle and fill in under the wheels with stones, logs, brushwood and even spare wheels.

Perforated plate, placed upside down (i.e. rough side up), will give more grip to the wheels; but sand ladders become slippery.

Trying to tow out a stuck vehicle, if the towing vehicle is also on mud, usually fails. If the stuck vehicle is of similar size to the rescue vehicle, 'snatch- tow' (Kinetic Energy Rope Recovery using the correct KERR ropes) is the most effective solution; but you must thoroughly understand the technique and its dangers.

When you return to paved road, clear as much mud as possible off the wheels and propeller shafts, because the extra weight will put them out of balance and cause damage. Drive steadily for ten minutes to clear the treads, or you could skid.

Crossing water

If a turbocharger is fitted, allow it to cool before entering water.

The latest vehicles may have catalytic converters; in rough terrain these break up and cold water destroys hot catalysts. For Third World use, remove the unit to avoid an expensive replacement on returning home. If you cannot do this, or will be wading back home, fit a raised exhaust outlet. Any serious wading in cold water can damage catalysts.

Coat petrol engine ignition components with silicone sealant, including any breather holes in the bottom of the distributor; clear these breather holes as soon as possible after the crossing. Silicone sealant is preferable to grease, which melts in hot climates and runs onto electrical contacts.

On Land Rover vehicles, fit the clutch bell housing wading plug and, where supplied, the camshaft drive belt housing wading plug. These plug the holes that drain any leaking oil to prevent it getting onto the camshaft timing belt or clutch-driven plate. They should be removed after wading - not necessarily immediately, but within a few days. For regular wading, leave these plugs fitted; but remove them weekly, allow any oil to drain out, and then replace them.

Late-model vehicles should have remote axle breather tubes, venting above the engine; check their condition regularly. Older vehicles may have Poppet valves; check that these are clean and in working order. Hot axles fitted with poppet valves, if stuck in water for any length of time, will produce a vacuum on cooling and suck water in through oil seals. Poppet valve systems are easily converted to remote breather tubes.

Inspect the water on foot first. In warm climates, avoid wading in bare feet: in slow- flowing water there may be Schistosomiasis (bilharzia). In Africa, going about in bare feet is asking for worm and tick infections. Waders are more sensible than Wellington boots, as there may be unseen deeper sections. Use a shovel or staff to prod for depth, boulders or soft sections.

Choose a sensible angle of drive into the water and out on the other side. You may flood your engine if the angle in is too steep, and may not be able to get up the other side if the angle is too difficult.

If the riverbed is soft, lower the tyre pressures. Fast-flowing rivers will be faster and deeper, with more difficult entry and exit, where they narrow. If possible choose a wider section. Moving or stagnant water with an unbroken surface may be deep and is more likely to have a silt bottom, which vehicles could sink into. Moving water with a rippling or broken surface usually denotes a stony bottom, will be shallower and clear of silt; this is easier to cross. If there are dry patches, you can break up your crossing into stages. Rivers fed by glaciers or melting snow will be at their slowest and lowest level at dawn.

If the water will reach above bumper level, fix a waterproof sheet across the front of the vehicle to help create an efficient bow wave. If a waterproof sheet is not available, consider crossing the water in reverse.

If the water will come above the fan, remove the fan belt to cut down the spray onto ignition components. This is important with nylon or aluminium fan blades, which may flex and damage the radiator core, and essential if you decide to wade in reverse or have to back out. Only remove a fan belt for short periods, since the water pump no longer operates.

If the water will come above the floor, raise any articles that could be damaged by it. Have the rear door open and all baggage lashed down. The vehicle may float slightly, therefore losing traction.

Vehicles in convoy should cross one at a time. On deep crossings, the rear of a vehicle and its chassis take in water, which pours out on climbing the far bank, making this slippery and more difficult for following vehicles. Later vehicles should try alternative exits or allow time for the exit to drain and dry out.

Cross difficult water in second gear, low-range four-wheel drive, with any centre differential locked in, and avoid changing gear while in the water. Keep engine speed high enough for the exhaust pressure to stop the back pressure of the water from stalling the engine. It is worth adjusting the engine tick-over speed to a faster setting. Forward speed should be high enough to create a small bow wave. The trough created behind this bow wave keeps the engine bay and side doors in shallower water, lessening any spray over the engine. A fast walking pace is about right; if spray comes over the bonnet you are going too fast. In very deep water you will require first gear, to push the wave of water ahead of the vehicle.

If you stall in the water, remove the sparking plugs or injectors and try driving out in bottom gear low-range on the starter motor. This works for short distances.

If the bow wave cannot be maintained and there is a chance of the water being deep enough to reach the air intake, switch off before the engine stops. This is essential with a diesel. Water does not compress, so catastrophic damage can occur.

If fast-moving water is above bumper height, keep the vehicle at 45 to the direction of flow. The full force of water at 90to the body will force the vehicle downstream and negate steering.

On easy crossings, keep the brakes dry by keeping your left foot lightly on the brake pedal. Once out of the water, dry out the brakes by driving for a few minutes this way. Disc brakes are self-cleaning, but drum brakes fill up with water and sediment; clean these regularly and don't forget the transmission brake.

If a petrol engine stalls or misfires, spraying WD-40 over all ignition components may get it firing again; if not, dry them all out thoroughly.

Flash floods in riverbeds

Although you may be in a river bed under a cloudless sky, heavy rain elsewhere can cause a flash flood that envelopes you. Most flash floods are seasonal, but freaks can occur at any time. Always be prepared and never camp overnight in a riverbed.

Where a riverbed has to be used in the rainy season, while driving upstream, watch out for possible flood-water. When driving downstream, have a passenger monitor the route behind you, while your own attention is on the terrain ahead.

Make mental notes of any places where you can quickly get up the bank out of danger. If you encounter flood-water coming down, get up the nearest bank. If this is not possible, drive quickly downstream to the first available escape route.

Third World ferries

Third World ferries should be embarked and disembarked in four-wheel drive with any centre differential locked in. This ensures that you do not push the ferry away from the bank, leaving your vehicle in the water.

Weak bridges

Inspect local bridges before using them. If there are signs that local vehicles cross the river instead of the bridge, then that is the safest way to go. If in doubt and the bridge cannot be avoided, unload the vehicle and cross slowly in four-wheel drive, with only the driver in the vehicle.

Snow and ice

Snow is deceptive because it does not always conform with the terrain it covers. In addition, areas subject to wind or shade may have black ice.

Off-road driving in snow will be easier at night, or in the early morning, when the snow is firmest and the mud below it frozen. As with sand, high-flotation tyres are an advantage on really deep snow. If they are fitted with snow chains, they should be at the correct pressures, not at low pressure, or the chains will damage them.

Snow chains should be located either on all four wheels, or on just the rear wheels. Having chains on just the front wheels will cause a spin if you touch the brakes going downhill. With vehicles that have large axle articulation, some designs of snow chains could sever the brake hoses, so check with your vehicle manufacturer before buying snow chains.

If the vehicle is empty, put some weight over the rear axle.

In very cold conditions, if you have a diesel engine, dilute the diesel fuel with one part of petrol to 15 parts of diesel, to stop it freezing up (use 1:10 for Arctic temperatures). This is illegal in the UK and could damage modern high-speed diesel engines, but is often necessary in the Third World.

On roads or tracks, keep to the middle to avoid sliding into ditches or culverts at the side. Drive slowly in four-wheel drive, in as high a gear as is possible, and avoid any sudden changes in speed or direction. Use the engine for braking.

If you drive into a drift, you will have to dig your vehicle out; it is easier to drive out backwards.

If you skid or spin, do not touch the brakes; depress the clutch, then, with all four wheels rolling free, you will regain control.

Convoy driving

Vehicles in convoy should be well spread out, so that each has room to manoeuvre, does not travel in another vehicle's dust, and has room to stop on firm ground should one or more vehicles get stuck. Adopt the system where any vehicle which gets stuck, or requires help, has its headlights switched onto mainbeam. This is particularly important in desert situations. All drivers should keep an eye out for headlights in their mirrors, as these can usually be seen when the vehicle cannot.

The last vehicle should have a good mechanic and a good spare wheel and tyre, to cover breakdowns.

Keep to the allotted convoy order to avoid confusion and unnecessary searches. The convoy leader should stop at regular intervals, to check that all is well with the other vehicles.