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Motorcycle Braking |
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This information was originally published in the
New Zealand Motorcycle Safety Consultants
Megarider eNewsletter You can subscribe to the Megarider eNewsletter: Send an email to nzmscon@paradise.net.nz with a request to go on the mailing list. 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. 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. 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. 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. 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. 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 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." 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. 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. 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. 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. 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. You'll fall off as the wheel will
eventually tuck under and the bike (and you) will fall down. 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. 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. 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, 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. Email address:
nzmscon@paradise.net.nz You can subscribe to the Megarider eNewsletter: Send an email to nzmscon@paradise.net.nz with a request to go on the mailing list. |
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