Basic Off-road Driving
For the purposes of this series of articles on off-road driving, imagine for the moment that an off-road driving club has recruited a new member- one that has never driven on so much as a graded dirt road, and has therefore joined a club to undergo some basic off-road driving training at first. It does not matter where the club is, it could be anywhere in South Africa, but what it does have, is access to a vast area of bushveld. This is their training area and it contains:
- deeply rutted and heavily cambered farm roads,
- some equally deeply rutted two wheel tracks,
- a large sand pit with long stretches of thick red and powdery white silicate sand,
- a 7 square km artificially created wetland with mud in varying depths and consistencies and with some medium sized trees growing near the edges,
- a small river with a rocky bottom (mud in other parts) which is prone to flooding, and which feeds a 10 000 square
- metre dam with varying depths and types of bottom,
- a 3 km long mountain pass at an average 24 degree incline and a few hairpin bends,
- some tracks going straight up and down the mountain, with two being rocky and another covered with grass and sand,
- and extensive granite outcroppings that are suitable for rock crawling.
It also used to contain some very wide and deep erosion ditches, known as “dongas”, but the club has successfully rehabilitated these dongas and as such, they play no further part in this story, and while this is not the perfect training area, it is better than most since it is the site of many local 4×4 driving competitions and events.
However, this is the new members’ first day in the training area, and much comment has been made by long-time club members on his choice of a 4WD vehicle, particularly its lack of electronic driving aids, which are considered essential equipment for inexperienced drivers. Nonetheless, it has a solid front axle and a 1-ton carrying capacity, both of which are also considered by many club members to be essential equipment and as such, a small counterfoil to the lack of electronic driving aids. The Instructor however, is more concerned with the fact that the new member has had absolutely no experience of driving on anything other than tarred roads and with this in mind, he decides against repeating his standard briefing on the various gear levers and the diagrams on them. Instead, he checks his own seat belt before checking that of the nervous new member before instructing him to set off down the stretch of rutted farm road leading to the sand pit.
Choosing your Line
Nodding, and somewhat nervous, the new member sets off, and the first few hundred meters pass without incident. However, the loose, gravelly surface causes the 4WD to feel skittish and unstable due to its inflexible bias-ply tyres and solid front axle, and in an attempt to counter this, he reduces speed from 60 km/h to 40 km/h, which causes an approving nod from the Instructor, as well as making the heavy 4×4 feel more stable. Changing to a lower gear, he carries on, but just around the first bend, he sees a series of deep ruts running diagonally across the road less than 50 metres away. However, being new at off-road driving, and having paid a lot of money for both the 4WD vehicle and expert instruction, he decides to impress the Instructor by tackling the ruts head-on.
Slamming on the brakes, which causes a skid, and nearly stalling the engine, he comes to a stop with one front wheel in a rut. Saying nothing but appreciating the Instructor insisting on them both wearing their seat belts, he engages reverse but the rut is too deep and the rear wheels just start spinning. Giving up the attempt, he struggles with the four-wheel drive engagement while the Instructor engages the free wheel hubs on the front axle, but he only manages to stall the engine, even in low range 4WD mode. He was led to believe that his 105 Series Cruiser can get out of anything, but he clearly seems to have been misled.
Deciding to intervene, the Instructor tells the new member to get out of the vehicle and look around him. “Look Bud”, he says, “do you remember what I told you about safety that goes hand in hand with choosing your line? Well, the safety issue here is that you did not adapt your speed to your environment: you could not see what was ahead of you- you were in unfamiliar terrain and if you had reduced speed accordingly, you would have been able to see the line other drivers had chosen around these ruts. Do you see there, to the left? That is where you could have gone around them without as much as a bump.”
“The other issue is that you could have broken the front axle, or worse. If you had gone any faster, we could have rolled over, or flipped. The only way to get out of this now is for you to get back in the vehicle and continue in low range 4WD in the direction you are facing. The rear wheel will follow you into the rut, which is when you reverse till you get to that point over there, where the other tracks cross the ruts, and where they are shallow enough to get out of without any problem.”
” And always remember, choosing your line correctly is the difference between successfully crossing an obstacle and/or ending up with broken bones or a wrecked vehicle, but bear in mind that the environment always comes first. If you absolutely have to make a detour through bush or grassland, do so with the minimum of damage, and if you have to dig your 4×4 out of a hole, repair the hole to prevent erosion damage in the future.”
“Also, remember that if you have to use stones and rocks to get your 4WD out of a hole, remove the rocks before you close up the hole, before some other person comes along when the track is muddy and therefore cannot see them. Running into the rocks you left there could break his axle or a wrist because of the unexpected steering kick-back, so always remove all the rocks you used to get yourself out of a hole.”
Shaken but more determined than ever to become the best off-road driver he could possibly be, the new member sets off again, but this time in high range 4WD. He had just learned the most important basic rule of off-road driving: BE ALERT, BE CAREFUL, AND BE SAFE, and he was never going to forget it, and was just about to say so when the Instructor spoke again:
“Listen Bud, you were lucky back there but don’t worry; even the best of us sometimes still get it wrong. However, as you get more used to the feel and power of your 4×4, you will learn just how much momentum you need to cross mud or sand obstacles, as well as how much braking force you need to stop in time to prevent you falling into ditches and ruts.”
“Momentum is as important as speed and gear selection but there are times when you want to reduce momentum without using the brakes, like on sand dunes for instance. On a dune with a loose surface you want to go straight down but because you have little or no directional control, you use engine braking, which prevents you running away, but also keeps the wheels rolling at a controlled rate at the same time.”
“When we get to the mud, I will show you how to swing the front wheels through a narrow steering angle to allow the front wheels to look for traction, in a manner of speaking. But when your off-road driving course is done you will know all about sand driving, mud driving, rock crawling, hill climbs, water crossings, driving in snow, and how to handle back roads. As you know, beach driving is against the law in South Africa, but we will get some driving on sea sand done in Namibia when we do our desert tour. All of this stuff is required knowledge for serious off-road driving in Southern Africa, and even more so in the rest of Africa, where there are just about no repair facilities, and where if you get stuck, you are on your own, buddy system or not.”
Off-road Driving and Choosing your Line
The new club member, Bud, was about to comment on all this when they stopped at the clubhouse after his first lesson in basic off-road driving, but the Instructor jumped in first:
“I cannot teach you to drive, but I can teach you 4WD vehicle control and how to choose your line when you approach an obstacle, regardless of whether the obstacle is sand, mud, rocks, or a water crossing. Choosing your line correctly is not only the most basic of all the off-road driving skills, it is also the most important because the correct line is the easiest way to cross obstacles successfully with the least amount of damage to the environment and your 4WD vehicle. So, if you keep coming back, we will teach you all you have to know about off-road driving before you tackle any sort of off-road driving excursion beyond the borders of South Africa.”
“And, oh yes, before I forget; you have a good 4×4 here, but I recommend you get something that has at least some electronic driving aids. You know, something like non-brake based traction control, and diff locks. You should maybe also think about getting an HDC, which is a system to control your speed while descending hills, as well as a rollover mitigation system, but that is entirely up to you- I just thought I would mention it. See you next week.”