Main roads and tracks avoid ergs as much as possible. It is too "moving" and after as little as a few month, it might be covered by a dune. On our trip 60km from In-Salah to Foggaret-ez-Zoua, we found that after 40 km, the excellent surfaced road was covered by a several meters dune and that a track avoided it.
When the road passes on a reg, wind will bring sand on the road. After a sand wind, there will be many sand drifts. Mind, sand is soft but a sand drift is not! A sand drift does not behave like a snowdrift but like hard rock. You must slow down, even for a small sand drift, otherwise, you might brake an important part of the car (suspension, collector, chassis, etc)
One trick upon driving on trails in the Sahara is when the trail passes on a reg or across the bed of an oued, which happens very often! In the beginning, there was a well-marked camel trail with "redjem", a few stones piled on one another from time to time. When cars and moreover trucks use the trail, after a while, some parts become sandy, with fech-fech and the next cars will try to escape the sandy part and drive a little apart, and apart and apart. In some places, there can be dozens of trails extending on several kilometers wide that can converge … or diverge.
The problem occurs when some sub-trails diverge! When you drive on a sub-track with a lot of tires marks and that progressively, they are less and less, beware! That means that previous drivers have realized that they were driving the wrong direction and made a U-turn to find the real track. They pass a second time on the same sub-track and this is why, in the beginning, there were so many tires tracks!
Generally speaking, if you do not drive fast enough, you might be more easily stuck, but if you drive too fast, you might hit a large stone, a pothole, a large tuft of grass. The driver must adapt very quickly to the situation and "feel" the track.
In French, a stupid popular sentence says “araignée du matin, chagrin, araignée du soir, espoir” (morning spider, sorrow, evening spider, hope), but this is only for the rythm! In the Sahara, on the countrary, we should say “morning sand, hope, evening sand, sorrow”.
When you know you will have to drive a difficult part, try to do it in the early morning, as the sand is more compact. Once warm, it will hold your car much less. On one occasion, we made a day trip (actually a half-day trip!) from I-n-Salah to Foggaret-es-Zoua, 70 km of very sandy trail, with a Peugeot 504. Going to Foggaret was easy. When coming back, late morning, we got stuck half way from crossing the bed of an oued. We had to work hard to free the car, push it on plaques, got stuck again, etc…
Look at the first photo. It is the off-road way to go out of the oued's bed and it is mildly climbing, which is why we got stuck.
The second photo is an enlargement of the first. In the foreground, you can see the marks of the stucking-in. Once the pushers, using shovels and plates have sweat to free the car, the driver, comfortably sat, must accelerate as much as possible and not stop until reaching a safe place, not to be stuck again while poor pushers holding shovels and plates must walk after the car and sweat again to reach it!
BTW, who took the photo? We were five in the car, four are walking, then what? I suppose that the driver-photographer, after having secured the car, ran down, far enough to make a good photo and then ran back to the car. After all, the driver had also a hard time and sweat a lot!
Why that? At night and in the morning, there is some moisture that covers the grains of sand, which allow Van Der Wals bonds to establish between the grains that will “stick” together. As soon as the sun warms the sand, water evaporates and the sand has less cohesion.
However, you cannot drive off-road everywhere in the Sahara. When the place is not suitable for off-road, you have to drive on a trail. When cars and trucks drive fast on a dirt road, after a while, it builds “waves” on the surface, called washboard (Tôle ondulée in French).
Thanks Glenn aka VT Bwana_Brown for giving me the English equivalent!
On washboard, you must either drive very slowly (10-20km/h), or faster than a given speed. That speed depends of the characteristics of the car (mostly the distance between axles), of the distance between the waves and of their height. The latter depends of the type of vehicles that built the washboard: trucks give a very hard washboard, high and long that requires a higher speed while light cars give a lower washboard, with tighter waves. Most of the time, you must drive 80-90km/h, but sometimes faster. When you accelerate, between 20km/h and 90km/h, you feel you are in a shaker and that the car is going to break into pieces. Once you have reached the required speed, suddenly everything is smooth and comfortable!
Your car is flying from the top of a wave to the top of the next one. That means that you have very little contact with the ground and very little grip to the road. If there is something unexpected on the road, you cannot do anything. It is fun driving but it requires to pay much attention, to forecast what might happen ahead and to “feel” the road.
though you feel comfortable, if you can have a look at the wheels and suspension of your car or of another car, you will be horrified. They work like mad to make you comfortable. No matter if the car is 4x4 or not. It must be STRONG. Light cars will not resist long on a washboard trail! When we had with us friends in a little Renault 4, it behaved bravely off-road and on washboard trail for a few days but got a serious breakdown : an electric wire got its insulation worn out by the vibrations, which gave an electric short cut that made the coat of the accelerator's cable sheath to melt and block it!
Of course, when there is a good surfaced road, you do not question whether it is possible to drive out of road or not.
In 1973, the road was just built between El-Goléa and In-Salah but not open yet.
On the way south, we had to use the old trail (first photo), along the new road
Every 50 meters, a row of stones was arranged so that you could not possibly use it (second photo) ! Too bad!
Luckily, on the way back, we could drive on the new road (third photo).
The fifth photo shows the huge road sign that standed during the road works.
Driving in the Sahara is fun but at the same time it is a very serious job. You will find along the roads and trails reminders of what might occur if you do not follow the guidelines!
I wanted to put this silly joke for those who know (well!) French on previous tip but I was short of space.
On ne dit pas "le congère" mais "le patron dirige"
Sand is very abrasive and if you do not take care, once back from the Sahara, you will have to change the headlights of your car as sand will have been entirely tarnished and will not light correctly.
It is very easy to avoid that by covering the headlights (and surrounding paint that will be protected at the same time) with a thin coat of grease. In the beginning, you see only the grease, light yellow (first photo).
After some time, it will take the color of sand (second photo) and when the coat is thicker, it is brown (photos 3 and 4).
However, if you do not pay enough attention, trousers will weep the grease! (photo 4)
Fech-fech is the fear of any traveler driving in the Sahara.
The first and second photos shows how fech-fech looks like but we will come back to this photo later.
The third picture is a drawing that shows on the left grains of “normal” sand. They are broken grains of silica and have angles. These angles prevent them from sliding too easily one over the other.
When many vehicles pass at the same place, they use the sand and progressively, each particle becomes a sphere. This is fech-fech. It has no cohesion at all. If you take it in your hand, it will flow like water. Needless to say, if you drive in fech-fech, you may “sink”, depending how deep it is. When you spot fech-fech, you must quickly chose : either accelerate to pass it as fast as possible if it is possible or brake and pass somewhere else.
Now, let us go back to the first and second photos : when the trail is fech-fech, the tracks left by previous cars look blurred while with regular sand they remain clearly printed. In that case, the fech-fech looked deep and long so I chose to stop and look for another passage, may be on the right.
When the sand is soft, a 4x4 is better but does not guarantee that you will be able to pass. On one travel, we were three cars. My Land-Rover never got stuck. The Toyota that came for the first time to the desert was heavily loaded and got stuck once but severely. It took almost one hour to take it out and tow it with the Land-Rover. The Renault 4, not 4x4 but light, got stuck several time in a difficult part of the travel but each time was very easily taken out, either by pushing it or by towing it with the Land-Rover.
In that case, the sand was especially tricky: the area was more or less salted and made a crust on top of the sand. When driving fast enough, you did not notice anything wrong but if you drove too slow or if the car was too heavy, the tires went through the crust and you got stuck!
This picture was taken in 1982. The road was built in 1972-73 but most of it was already in very poor condition. Building a road requires a lot of water in order to pack properly the soil. Apparently, the work, performed by the army, had not been done well and only 6 years later, it was much more comfortable to drive out of road than on the "surfaced" road. You could drive OFF-road with a regular car (as usually) while driving ON the road required a 4x4! This is why in 1982, we chose to drive off-road!
Most visitors feel that a 4x4 is a must to go to the Sahara. This not true and there are plenty of locations in the Sahara where you do not need a 4x4 at all, even off road (look at locals!) ! In other places, a 4x4 will be safer.
Look at the photos, shot in 1982 on the Tademaït Plateau, a reg (I explain in another tip what is a reg). Even a small car (a Renault-5) not designed for out of road driving can do it! No problem and the driver had fun!