1. Which brake is the most effective?
The front brake is the most effective, giving between 60 & 80% of the bike's stopping power in hard stops, depending upon surface conditions. This is because most of the weight of the bike and rider transfers forward onto the front wheel when the brakes are applied. A common example of weight transfer is when you trip on a gutter - your feet stop but momentum keeps the top of you going and you fall flat on your face. The weight transfer that takes place under braking on a motorcycle pushes the front wheel onto the ground and makes it grip very well.
2. Is the front wheel likely to skid if you apply the front brake hard?
No. The front wheel is likely to skid uncontrollably and bring you down only if you jam the front brake on hard. If you apply the front brake in a staged (progressive) process, the front wheel may skid but that skid is normally quite controllable.
3. Is the rear wheel likely to skid if you apply the brakes hard?
With most of the weight being on the front wheel, the rear wheel tends to be light under braking and will therefore lock up and skid very easily.
4. How do you control a rear wheel skid?
Control of a rear wheel skid is easy. Just keep your eyes up to the horizon and look where you WANT to go (not necessarily where you are actually going) and the bike will skid in a controllable manner with a minimum of fishtailing. Basic and advanced braking techniques are best learnt under controlled conditions rather than when a truck pulls out on you! Your local motorcycle school will run a fun braking exercise session for you and some mates if you care to call the school and arrange it.
5. Is braking a natural skill?
Braking, as with any riding skill, is a learned skill, not a natural one. This means you must practice the correct braking skills enough to make them an instinctive reaction before you can be sure that you will do the right things in an emergency. Overseas research has shown that, because of panic overpowering the rider's conscious reactions, nearly a third of all riders do absolutely nothing in an accident situation: they don't even apply the brakes!
If, however, your high level braking skills are so well learnt that they are instinctive, you will do it right, no matter what the situation. However, this requires you to do a lot of high level braking skill practice, the skills will not come with normal everyday riding.
6. Is there a special braking technique that ensures that a rider will get the best out of a motorcycle's brakes?
Yes. The process is called STAGED BRAKING and it involves the rider applying the motorcycle's brakes in a staged process. This gives the rider predictable, progressive braking.
7. In an emergency do we concentrate on using staged braking on both front and back brakes?
This is a controversial subject. Some experienced riders reckon that, even in an emergency when research has shown that panic tends to decrease your riding skills, they can apply the back brake perfectly with no loss of braking on the front. Well, research has shown that the average rider can only properly concentrate on the use of one brake in an emergency so, unless you think you're road motorcycling's equivalent of a top motorcycle racer, we would suggest that you concentrate on getting the best out
of one brake. Of the front and rear brake on a motorcycle, the one to concentrate on in an emergency is the front brake because if you get that one wrong, lock it up and don't correct that problem then you're going to crash..
According to the American Motorcycle Safety Foundation, if you try to get the best out of both brakes in an emergency, you will get the best out of neither. The MSF says you can't concentrate FULLY on both brakes at one time. You know your mother's old nag, "You can't concentrate on two things at one time"!
So, to get the best braking, you have to concentrate using either the front or the back brake and, since the front brake gives up to 80% of your braking power and incorrect application is likely to make you fall off, it makes sense to concentrate on the front brake.
The American Motorcycle Safety Foundation teaches their instructors that "in an emergency braking situation you should apply the back brake hard and let the back wheel slide if it wants to. This way you can concentrate on what is happening up front; there's enough to think about in the use of the front brake."
8. So how should I apply the rear brake?
Apply it and forget about it. Let the back wheel skid if necessary. Concentrate on using staged braking to harness the superior power of the front brake to save your life.
9. Is Staged Braking difficult to learn?
Given practice, the skill is not difficult to learn. The best way to learn it is to start off with a four stage application of the front brake. Later you can increase the number of stages to make your braking more and more progressive, if you want to.
10.Can you explain four stage braking in practical terms?
To understand four stage braking, think of a rider coming up to a set of lights. Stage One is the force with which he applies the front brake when he sees the lights turn orange some way ahead, in other words, lightly.
At Stage One, the rider is applying the front brake to the point where the brake is just on and slowing the bike down very, very gently to roll to a stop.
Stage Two is the force the rider would use if he was a bit closer to the lights when they turned orange, and he had to make a normal, smooth stop at the lights. So, Stage Two is the firm pull used to bring the bike to a firm, but quiet stop. The rider applies his front brake to Stage One (friction point) before going on to apply to a steady force at Stage Two.
Stage Three. Our rider has dithered about whether to stop for the orange light before deciding he'd better. By this time, he has to stop quite hard to stop. So he applies the front brake to friction point (Stage One), then onto a firm pull (Stage Two) before applying pressure with a strong pull at Stage Three.
Stage Four. The rider very unwisely decides to run the orange only to find, just before he reaches the lights, that they turn red. In this serious situation the rider needs all the braking he's got. So he applies the front brake to friction point, moves onto the firm pull of Stage Two, then to the strong pull of Stage Three, before giving it all he's got at Stage Four.
11. If you "give it all you've got" on the front brake at Stage Four, won't you get front wheel lockup?
Possibly but by using the staged braking process, by the time the tyre gets to the point of locking up at Stage Four, the weight has transferred forward onto the front wheel and any tendency of the front tyre to lose grip is both easily sensed and controlled, unlike a front wheel skid caused by a tyre locking up when the brake is jammed on hard while weight is moving around on the bike under weight transfer.
With correct use of the Four Stage process, controlling a front wheel skid is simply a matter of keeping the wheel steering straight ahead as you relax pressure on the front brake to allow the wheel to revolve again and regain grip.
12. What will happen if the front wheel locks and I don't relax some pressure?
You'll fall off as the wheel will eventually tuck under and the bike (and you) will fall down.
13. How good can you get at emergency braking?
In emergency stops, expert riders are capable of controlling a front wheel skid by releasing pressure on the front brake just enough to get that wheel turning again without actually letting the brake right off. This requires considerable sensitivity on the brakes and the only way you will gain this sort of sensitivity is to practice.
At the NZMSC higher level Megarider sessions, the way the instructors tell if the pupil has reached a suitable standard is whether they can hear the front tyre chattering as the tyre grips at the point of adhesion during emergency stops.
14. Is a bald tyre a liability when braking?
A treadless tyre will quite adequately handle braking stresses on a perfect road surface. The trouble is that perfect road surfaces are more than rare - they're virtually extinct. Tyre tread acts like a broom, sweeping debris, dirt, gravel and water etc off the road surface in order that the tyre can grip the road.
The tread on a sensibly ridden motorcycle can comfortably handle most foreign matter on a road surface - with the possible exception of oil (especially diesel oil), thick mud, and smooth wet paint. But link a bald tyre with foreign matter on the road surface and throw in braking stresses for good measure, and the crash will resound throughout the neighbourhood.
15. How should I brake on slippery and loose surfaces.
Carefully but not timidly. The secret to good braking on poor surfaces is observation. If you know what's under your wheels you can tailor your braking to the surface.
So, keep an eye on the road surface. If you cross a slippery surface under strong braking the front wheel may lock. This is why riders who brake late and hard for orange or red lights often spill off - into the middle of the intersection. The fall occurs because the rider fails to ease the front brake as the front wheel crosses the white line that crosses the lanes at the edge of the intersection. Then the front wheel breaks loose under braking on the slippery surface, the rider panics and freezes,
and he and his bike head groundwards...
The basic requirements for braking on a loose surface such as gravel are the same as those applying to braking on a sealed surface. The difference is that you must observe the requirements more strictly on gravel.
You must brake in plenty of time, preferably brake while upright and in a straight line (any braking while leaned over in gravel is extremely hazardous), use both brakes very progressively, carefully interpret the noise from the front and rear tyre while braking to detect and counteract any wheel lock-up, know your road surface, and take particular care when braking on gradients, inclines, and heavy cambers.
Source:
www.webbikeworld.com 
20th July 2006, 23:18
