Desert driving

When people think about desert driving they usually think about getting stuck in the sand. But actually in the desert you can spend as much time driving over gravel, rocks, and vegetation - albeit sparse vegetation - as you do driving over sand.

 

Tyres

Hard tyres are fine for hard surfaces but if your tyres are too hard then you will sink when you do finally hit the sand. On the other hand, if they don’t have enough air in them then you are likely to get a puncture when you weave your way through an area of sharp rocks. Many people carry a small compressor to reinflate tyres. A foot pump is not very good because it will get sand in it and chances are it will eventually break. In Germany and France you can get quite effective handpumps which though they are time consuming you can refill the air in a tyre.

 

One of the advantages of driving with a wide tyre such as Pirelli scorpions 10.5 inchx15 tyres such as I use is that you can let a lot of air out of them without there being a significant collapse on the side wall. I often only reinflate my tyres when I am at an Oasis having driven 100 or more road km on tyres at 20PSI. In four years and 30,000km on the same tyres I've suffered only one sidewall blow out on tarmac. I’ve driven extensively on sand and on rocky surfaces that are quite sharp and not suffered many punctures. People with narrower tyres than mine, such as 7.5 inchX16 have in my experience suffered more punctures.

 

Basic equipment you will need.

You will need a jack.

Conventional wisdom suggests either a highlift jack or an airjack. Highlift jacks are unavailable in Egypt or very difficult to find, they are very heavy to bring through customs and they also suffer from being dangerous if you jack on a sweaty hot day without paying much attention, or with someone else using the jack which is quite common and you have it resting on soft sand. An airbag jack will therefore work better but airbag jacks take up space in the car and they can damage pipe work underneath the car. An airbag jack is very useful if the car rolls as you can use the jack to progressively lift the car. Having said that I have discovered through trial and error that the best jack is the mechanic’s long arm lifting jack the so-called hydraulic jack; but not the small model used by motorists because in the desert situation you need a much higher lifting capacity. You need to be prepared for the car being so embedded that the differentials are resting on the sand and the wheels can get no grip at at all. You then use the hydraulic jack to raise the suspension so much that the wheel lifts up and sand can be shoveled underneath it. So you need the big size of hydraulic jack. Not the 6 foot hydraulic jack but the 3 foot hydraulic jack. This will take up space and it weighs more than a highlift jack but it’s much safer and much easier to use.

 

Next you will need sand plates.

You can get by with two full-sized sand plates. That is a piece of aluminium with holes in it about four ½ feet long. If you get really stuck four sand plates are better. Don’t cut them in half as they will bend more easily and the sharp edges will snag on things.

 

Basic skills

You have to develop an instinct about what to do when you get stuck. You can feel the car digging in, you can feel the wheels turning up sand; your instinct is to tread on the accelerator and go faster. That’s the wrong thing to do. What you really want to do is slow right down until the wheels are just turning and you are moving forward. However slowly you are moving forward as long as you’re moving forward you will escape. Sit looking out of the side window at the wheels to check you are actually going forward. As soon as the vehicle, as opposed to the wheels, stops moving forward the wheels will just begin to dig in again - so stop - but with a gentle motion, not the brake - use the clutch to disengage slowly.

 

If you swerve from side to side in soft sand you can often get more traction. But the single best tactic crossing soft sand is letting out air from your tyres. It makes an incredible difference. If you drop the tyre pressure from say 30 PSI which is a fairly usual road pressure down to 22 PSI you will find that you will not get stuck very often. If you do get stuck you can drop it even lower to around 15 PSI but you will need to reinflate that tyre fairly soon afterwards. You can go down to 10PSI if you drive really carefully. Using tubeless tyres is easier, cheaper and you are less likely to snag the innertube if you really drop the tyre pressure.

 

When you are driving on sand it’s easy when the sand is flat. The difficulties happen when you are driving over dunes. Dunes can be split into three varieties (for driving purposes).

Whaleback dunes, which are shallow sloping dunes which have hard sand on every side literally rising up from the flat desert like a whale’s back. You then have a ridge dune which has a hard surface on one side and a crumbly surface, the so-called slip face on the other side. Usually the hard surface is more on the side where the wind is blowing from and the soft surface is where the wind has deposited grains though this is not the always the case. And the third variety which is halfway between the two is the sharp drop off from a whaleback dune. You’re driving along quite happily perhaps on the top of a very flat whaleback dune and suddenly there’s a drop which is a very steep looking slip face of soft sand. These are not the technical descriptions of dunes because obviously sand dunes fall into other categories such as the sieff dune which is a long dune, sword shaped if you like, and the barchan dune which is crescent shaped and then the star shaped dune which is made up of several barchans. But in terms of driving these three are the kind that you encounter out there.

 

The ridge dune you can approach by simply driving fast going up the hard surface stopping at the top, then aligning your car perpendicular to the slope going down, shifting into first gear, moving off slowly and simply cruising down that surface without using the brakes. If you start to swerve and use the brakes it will intensify this movement and you may roll. So if you do start to go off course you should give it some more acceleration to straighten up. But the best technique is to be absolutely perpendicular to the slope and just trust that you will go straight down, the four wheels effectively acting like rudders or small keels keeping you straight. No slip face is more than about 35/36 degrees depending on the dampness of the sand. You can get steeper slopes in hard sand if it is wet. Ideally if you’re going to go over a ridge it makes sense to scout it out to know what is happening at the top. On the other hand maybe with a very big ridge you don’t want to do that in which case you have to time your ascent so that when you get to the top you can stop - ideally without slamming the brakes on which will only serve to dig you in.

 

When you’re driving on a whale back dune the thing to look for is the horizon of the dune: if this seems to be quite sharp and unchanging as you rise up the dune chances are there is a drop-off and you need to be careful about this. If on the other hand as you shoot up the side of a whale back dune the top seems to merge with the rest of the horizon it means there isn’t a hard drop off - just a slope you can drive down easily. But at midday, when shadows are short, you can be surprised so you need to be careful. Over time you develop a sort of inkling about where drops are likely to occur. For example most dune systems in Egypt run from the North West to the Southeast and the drop-offs are usually on the western side of the dune. So you can usually cruise up the eastern side quite easily. This is not obviously an exhaustive remedy but it is a good guide or starting point.

 

In general speed is your friend when driving over soft sand. Just as useful is the ability to maintain a constant speed without jerky stops and starts. Often the slamming on of the brakes or harsh acceleration is what takes you into the sand. A certain kind of hygiene if you like is a good idea in desert driving. For example, only park on a slope with the front facing down so that when you get in the car again you can roll to start without digging in. Or else park on areas where there are pebbles so you don’t sink in. If you do get stuck you can often escape if everyone jumps out and gives you a push before you’ve become too dug in. You don’t want to swear and panic, you need to take your time and carefully work out a way of extracting yourself. When digging away the sand from around the tires it is best to dig more than you think you need. Chances are if you just make a few scrapes the car will simply dig in further. It’s much better to dig four channels from each tyre, lay down sand plates and give the car a push and escape in one go. Repeated attempts of a half-hearted nature can simply result in the car becoming hopelessly bogged down.

 

The one area where you can sink very deeply indeed in Egypt is sabkha sand. This is sand which is very close to the water table and is supersaturated and usually has a high salt content. It can often be a thin surface of sand on a salt pan and the car sinks straight through it. These occur most often in the Qattara depression on the northern coast, but they also exist in parts of the white desert. Extraction from sabkha is hard if not impossible without another vehicle. And the best piece of equipment is a high tensile steel cable which should be at the least 100 feet long so that the other vehicle or vehicles can be a good distance away from the soft sand as they tow you out.

 

Other desert driving obstacles include navigating bumps and rocks. Driving slowly is the key here as hitting a bump at high speed can damage the suspension and hitting a rock at high-speed can damage tires. Driving over small bushes of tamerisk and other thorny vegetation can result in punctures so these are best avoided.