Motorcycle
Riding Techniques
©
2002 - 2008, Raymond Wood
Motorcycle Controls
These are devices that enable us to control the behaviour of the motorcycle.
Our first introduction to the controls of a bike include: Clutch, Throttle, Gears, Brakes, Handle Bars, etc. But there is one "control" whose understanding is fundamental to controlling the behaviour of the motorcycle:
The Suspension
Having a better understanding of the way the suspension works on a motorcycle helps to answer many of the common questions like: "Which brake should I use", "When should I brake when negotiating a bend", "When do I lay on the power in a bend", "What should I do if I go into a bend too fast"
Let's look at what happens to the suspension when braking and accelerating in a straight line:
You can see that during braking (also rolling off the power) that the weight (centre of gravity) of the bike moves toward the front wheel (and away from the rear wheel!). You can now see that, under heavy braking, the rear wheel becomes less effective as it has less adhesion to the road surface. It is likely to lock up entirely if used under a severe scrubbing of speed. Conversely, you can now see that gradually applying the front brake forces the front wheel harder into the road and giving more grip for the tyre to slow the bike - more brake - more grip - less speed.
Ok, so how should this affect our riding? Well, for a start, we can see that the best brake to use (in dry riding conditions) is the front brake. We can also see that losing speed in a bend is not a good idea! This puts more stress on the front tyre and is likely to cause it to lose grip and cause a low end slide or the front to give way.
This is now starting to make us think of how we control the suspension in a bend. The best geometry for a motorcycle in a bend is for the suspension to be pushing the rear (power) tyre to the road surface. This means either maintaining power or accelerating round the bend.
It is also clear that we should ensure to arrive at the turning point of the bend at the right speed so that we can either maintain the power or accelerate round the bend.
If you haven't gone into a bend too fast then ignore the following!
Our natural survival reaction in this situation is to roll off the power and/or brake. You can now see that, in fact, this is the worse thing we can do! Why? Because you will be loading the front tyre while it is cranked over at an angle plus, rolling off the power will cause the bike to stand up and go even wider than we are already dreading! The correct response to this situation is to crank the bike over even further (counter-steering) and applying even more power (something that most of us have to be convinced of doing and forcing ourselves to implement based on logic).
The throttle will nearly always get you out of more trouble than the brake!
You have a Stabiliser
The spinning rear wheel provides gyroscopic stability to over 80% of your motorcycle (including yourself) because it is directly connected via its axle/swing-arm to the frame of the motorcycle. The front-end is only indirectly influenced by the spinning rear wheel.
Proof that the rear wheel is directing the course of the bike is easy to see when you consider a motorcycle that is performing a 'wheelie'. Whether it is going in a straight line or it is in a bend, the motorcycle will continue that course even while the front wheel is off the ground.
If you lock your rear brake and cause a skid, the motorcycle does not simply drag the rear tyre along in a straight line - the motorcycle is deprived of the stabilizing effect of a spinning rear wheel and it will try to fall over to one side or the other. On the other hand, if you lock your front brake (while going straight) and cause the front tyre to skid, there is every reason to believe that (so long as the rear wheel continues to spin with some speed and you leave the front wheel pointing straight ahead) the bike will continue to stand vertical and track straight while you correct the problem (by releasing the front brake lever.)