#101 Learning off-road driving

Reaching the starting point of a mountain expedition often means driving on battered tracks, through fords, snow or rock fields. Mastering off-road driving is a useful skill even for those who are not behind the wheel: the driver may need to rest, get injured or lack experience on a difficult section. Knowing how to take over reduces the risk and limits stress on the approach. This page lays the foundations for tackling off-road driving in mountainous terrain.

The different types of terrain

Off-road driving in the mountains comes in the form of different surfaces, namely:

It is essential to drive only on tracks intended for that purpose. Driving off-trail severely degrades the ecosystem and leaves lasting traces. See #101 - Protecting our environment. Each of these surfaces is an obstacle to progression. Some are simple, such as classic tracks, others clearly complicated, like ford crossings. Of course, you can end up with a combination of obstacles, such as a track running along a cliff, covered in snow, sitting on a thin layer of ice. The goal now is to learn to recognize these obstacles and anticipate them during preparation, so as to tackle them with the right skill and a suitable vehicle. The following sections detail each of these aspects.

Recognizing obstacles

An effective method for recognizing obstacles is to mentally cut the track ahead of you into segments. The end of each segment must be visible, with an area where you are sure you can stop and get going again. All that remains is then to adapt your driving to the terrain making up the segment. This mental segmenting keeps the brain quite busy. The consequence is that off-road driving is much slower than on a conventional road. Experience will let you pick up the pace, but when in doubt, it is better to slow down to avoid losing control. Nor is it uncommon in off-road driving to get out of the vehicle to scout the terrain. Example: without prior scouting, a seemingly simple bend can conceal a mud hole several hundred metres long. A vehicle bogged down far from the road can require considerable resources to be extracted. Scouting on foot before dubious passages is a basic rule. The driving position is important so as not to be caught out by the terrain. The most important thing is to place your hands on the outside of the steering wheel (thumbs included). A rock can indeed knock the steering, the wheel spinning suddenly and potentially breaking a hand or a finger in its path. As for the pedals, use them as gently as possible, so that the vehicle is not jerky. The off-road adage is to go as slowly as possible and as fast as necessary. Finally, if the obstacle is insurmountable, there is no shame in turning back.

Anticipating the route

Just as you prepare your route in the mountains, you will need to look at the characteristics of the driving itinerary. The first point of preparation is the route itself. From a map (better, from several), you will need to identify the obstacles that seem obvious and the bends that look dangerous. Also remember to check whether a permit is required to pass. It is also useful to identify where you can park the vehicle, whether there are spots suited to turning around and others for setting up camp. You can then note everything down (such obstacle at such distance) on a piece of paper that you will take with you. You can also make a GPX track, on which to create points of interest identifying the risk areas. The second point of preparation is the weather along the route. Of course, chances are you already have weather forecasts for your expedition. These forecasts must be supplemented with a recent history for the track you are going to take. Precipitation can indeed create a mud hole, make a watercourse more powerful or put snow on your route. Also think about the return trip.

The mechanical components of off-road driving

To drive off-road, you obviously need a vehicle. Its important characteristics are:

Of course, one thing is still missing from all this: the type of transmission. Vehicles are generally two-wheel drive. Some two-wheel-drive vehicles have a reinforced differential, increasing performance on soft ground. Those dedicated to off-roading are four-wheel drive. With or without differential locks (1, 2 or 3). With or without a transfer case, providing low-range gears. In any case, the tyres will matter more than the type of transmission: a monster 4x4 with summer tyres will be less useful in the snow than a 4L with snow tyres.

Adjusting your tyre pressure

A tyre is designed to carry a load below a maximum speed. For that, an air pressure must be respected. On the road, it is very important to drive with the correct pressures to avoid accidents and major damage. Off-road, however, speed is often lower. The tyre heats up less, opening up the possibility of lowering the pressure. Reducing the pressure will increase the contact area between the tyre and the ground. A larger area means less sinking into the ground and a reduced risk of getting bogged down. Reducing the pressure also reduces the tyre's rigidity, so it deforms more easily to absorb impacts. Airing down is very useful when the ground is soft (sand, mud, etc.) or when it is very uneven. The lower pressure limit will depend on the tyre model, but it is not uncommon for off-road tyres to be able to go down to 1.5 bar. A guide from Overland Journal recommends, for example, reducing pressure by 25% on tracks, 30-35% on rock fields and harder trails, and 50% on sand. Experience will dictate how far to go, but remember that when reducing the pressure, the tyre must still be able to carry the load, and speed must be greatly reduced (20 km/h max at 1.5 bar, for example). If you plan to air down your tyres, you will need to plan for a bit of gear. A pressure gauge first, to measure the pressure and know what you are doing. Then a compressor to reinflate to the correct pressure once the off-road section is over. You can also use a bicycle floor pump (check that it is compatible with car valves), but depending on the size of your tyres, it can take a while…

A few driving tips

Below are a few basics for tackling each classic off-road obstacle.

The mountainside passage

The danger here is falling. Yours if you are next to a precipice. Of rocks or other objects if you are passing at the foot of a cliff. Before passing, stop to:

Then drive through quickly to minimize the exposure time.

The ford crossing

The dangers here are getting bogged down, flooding the engine or being swept away by the current. Before crossing the ford, stop to:

Then enter the water slowly at a constant speed, and once the ford has been crossed, reinflate the tyres and check the state of the vehicle. If you stalled in the water, do not restart the engine: water can flood the engine via the exhaust and the air intake. It is better to get towed.

The mud hole crossing

The danger here is getting stuck in the mud, or even losing control of the vehicle if you are on a sideways slope. Before crossing the mud hole, stop to:

- To cross the mud hole:

Climbing a slope

Climbing steep slopes quickly becomes impressive in a car. If the slope ahead of you is smaller than your vehicle's maximum climbable gradient:

Descending a slope

Same story as for the climb: descending a steep slope is always an impressive moment. To descend a slope:

Driving on snow and ice

The dangers here are losing control of the vehicle. Recommendation number 1 is to reduce your speed. To drive on snow:

For driving on ice, the best advice is to be equipped with studded tyres if the icy section is long. If it is short, follow the same advice as for snow while reducing your speed even further.

Crossing a ditch

The danger here is getting stuck in the ditch, with no way of getting out on your own without a winch. To cross a ditch:

Crossing a rock field

Crossing a rock field amounts to clearing several steps of varying heights. The danger here is damaging the vehicle. If your ground clearance is sufficient, here are a few tips for clearing a step:

Final preparations before setting off

You know where you are going to put your wheels and your driving is dialled in. Good. Now it is time to consider these various points:

If you plan to leave your vehicle parked on site for the duration of your expedition, it can be useful to bring a second set of keys. These car keys will offer a backup solution if you lose the first ones. Remember to entrust them to another member of the group. Finally, it is also useful to bring a booster to help a slightly weak battery, or even to disconnect the battery when setting off to avoid unpleasant surprises on your return.

The final word

Off-road driving is a skill often neglected by mountain athletes. Developing it reduces the risks during approaches and lets you start an expedition in better conditions. It is acquired with experience, ideally supervised by a local 4x4 club, which lets you be exposed to the common difficulties with an appropriate safety net.