By Alan Lowe
I considered inserting this into my article on motorcycle riding but I felt that the two were not compatible, despite their two wheel relationship. The other article covers a lot of the basics. This article assumes you are reasonably comfortable on a motorcycle even on the dirt.
If you don't know how to ride a motorcycle, then dirtbikes are a way to learn a whole lot, very quickly. This includes those people who can mount a motorcycle and travel from point A to point B but very little else. However, this article does not attempt to train the beginner. There is too much information there which is beyond the scope of this text (don't you just love that phrase?).
The first time you hit deep sand at low speed, you will find that the bike will not steer very well. No matter how expensive the bike is or what brand of motocross tyres are fitted, riding slowly in deep sand is one of the most daunting of dirtbike experiences, second only to deep river crossing.
I don't think I ever had the courage to ride fast on deep sand. I thought if slow was impossible, fast was out of the question. Then one day, I was riding at about 70 kilometres per hour along a limestone track when I encountered a stretch of deep sand.
Well, my life passed before my eyes in a flash, but the bike was holding steady and I could even steer it. The sand passed and I was back on limestone but the memory dug deep. I thought about that for some time and eventually worked up the courage to try some dune riding.
I went to Lancelin which is famous for its expanse of sand and dunes. People were riding dirt bikes on the sand with, apparently, no trouble. I ventured onto the sand and found that the bike would not steer. So, I gritted my teeth and gave it some throttle and as the speed picked up, so did the stability.
I eventually found that 100kph in deep sand feels like bitumen. However, it feels like oily bitumen when you are travelling in a straight line. The idea of turning feels like a ticket to the loony bin. But when you actually begin to turn, you find that there is so much traction that you can really crank the bike over in the turn.
One of the nicest feelings is to perform power slides on deep sand with both feet planted on the pegs. The bike will slide out to a point but will slide no further. Naturally, uneven surfaces will cause the bike to jump around somewhat but a fist full of throttle will usually pull you out of a nasty situation.
In next to no time, you will be riding over stretches of sand with no worries which is good because it prepares you for the next step. Where possible, get off the smooth stuff and ride over your own tracks again and again. Preferably, find some 4WD tracks or dune hopper tracks and try riding in those. You will find that the bike will try to follow tyre trails in the sand. The mistake most people make is thinking that the bike will follow these tracks unfailingly.
The bike will leave the tracks if asked to do so and will do it reasonably easily. You must be prepared for a slight reluctance of the bike to leave the trail which may cause a more savage turn out of the rut than you were expecting. But it will leave the rut.
The difficulty in this manoevre is when there are trees either side of the trail. You may need some room to move that the trees are not going to give you. This is where you use your body weight and the throttle. You can move around quite a bit against the movements of the bike and soon you learn to predict what the bike is going to do and you can move before it does. It makes for a very smooth ride on a very rough surface.
When the bike gets a little ragged, you can open the throttle to straighten the bike out. This is the procedure when the bike begins to turn sideways. When it lands, it flicks around presenting its other side to the direction of travel, when it lands again it flicks the first side around and so on. Many people simply bail out here. It is what most people do with someone elses bike. They blame the bike and sue the owner.
It happens when the bike finds a rut formed by a vehicle that has turned sharply off the track. The bike tries to follow this rut, leaps over the berm formed by the rut and begins twisting sideways through the air.
The trick is to keep your eyes on the track and be prepared when you see the wheel marks going somewhere that you don't want to go. Before you reach the spot, squeeze the bike between your legs to help keep you on board, lean toward the rear of the bike and open the throttle. This will normally keep the bike straight and you won't experience anything close to trouble when you cross over the rough ground.
If the bike does start to flick to alternate sides, try to keep your head and upper body moving in a straight line, allowing the bike to do whatever it wants to as long as that does not include throwing you into the weeds. You will find that the bike can move a great deal while your head and upper body do not. It becomes easy after a while.
When you are riding over sand dunes, you will experience some amount of airtime, the quality of which depends on three basic elements:
The takeoff should be done with a little bit of throttle to keep the front wheel up. Leaving a jump with a trailing throttle will cause the front wheel to drop and you will end up going over the bars.
There are times when you will want the front wheel to drop. For example, when the landing is a steep downhill slope, it is much better to land on the front wheel than the rear wheel. When the landing is to be done on a level surface, a rear wheel touchdown is usually more comfortable.
The flight can be controlled in several ways:
Roll - the action of the bike spinning around an imaginary line running from the front of the bike to the back of the bike - can be controlled by weighting one of the footpegs.
Pitch - the action of the bike spinning around an imaginary line passing from one side of the bike to the other - can be controlled with the rear brake and the throttle, even in mid-air.
Yaw - the action of the bike spinning around an imaginary line passing from the top of the bike to the bottom - can be controlled using your legs.
To be more precise with the description of yaw correction is difficult. When you realise the bike is twisting in a certain direction, you can flick it back using your legs and the bike responds even though you don't really know what you did. Equal and opposite forces within a closed system give a zero nett result. You and the bike are a closed system. Any movement you make is countered by an equal and opposite force which ends up doing nothing.
My only suggestion is that an external force is applied from somewhere which allows you to correct yaw even though you are an integral part of the system. The force must come from the spinning wheels. In particular, the spinning front wheel. If you were to stop that front wheel from spinning, I wonder how much you could correct yaw?
So, you push against the rear of the bike using the handlebar which is held in place, more or less, by the gyroscopic force acting on the front wheel. The result is that the rear of the bike moves in the other direction. This explanation does not sound entirely satisfactory to me but I get the desired result.
This leaves landing, which depends on the angle of the surface you are landing on. A flat surface is okay for a rear wheel landing. The front wheel should touch down first on a downhill or uphill slope. If you were to land on your rear wheel on a downhill slope, you are more than likely to land too savagely, compressing the rear suspension too much and having it kick you over the bars. Same for an uphill slope.
If the front wheel lands first and rebounds too savagely, the result would be a mono which you can probably handle and would look really cool anyway. The only problem is a front wheel landing where the front forks are sloping forward. Sometimes this can cause the front wheel to flip right around. Since it is limited in its travel in this way, you end up eating dust. So try to keep to a shallow angle and land on the front wheel first on slopes and the rear wheel first on flat terrain. In all cases, keep the angle of the bike fairly shallow and you should experience no great difficulty.
To correct the attitude of the bike - the angle of flight whether nose up or nose down - does take some practise but it does work well. If the nose is too high, pull in the clutch and hit the rear brake. This will stop the rear wheel but the momentum of the wheel will be transferred to the mass of the bike causing it to begin to rotate in the direction that the rear wheel was recently turning.
It is a matter of conserving the momentum of a closed system. The rear wheel had a lot of momentum which was passed on to the bike and the rider when the brakes were applied. That energy of motion had to go somewhere and it did not bleed off into the air. It was passed on to the rest of the system which began to move in the same direction.
Similarly, if you find the nose dropping too far, you grab a handful of throttle and start the rear wheel spinning. Once again it is the momentum of the rear wheel - in this case doing nothing - that must be overcome in order to get it moving. In doing this, the rest of the bike, including the rider, is forced to move in the opposite direction which results in the nose lifting. In this case the energy of motion was supplied by the motor through to the rear wheel.
There is a certain amount you can do by jerking the handlebars up or down to correct attitude. You can't do much nor will the effect last for very long because you begin moving in the opposite direction and eventually, you will have to stop moving again. This will produce an equal and opposite force which will cancel the corrective action applied previously. However, the effect may last until you touch down safely and that will be enough.