http://www.sportrider.com/ride/146_0703_traction_limit/index.html
Traction Limit - Riding Skills Series

You've Passed The Traction Limit- Now What?





In the previous RSS (Dec. '06), we discussed how our sense of speed can be
impaired by panic, causing us to think that we're entering a corner too fast.
This often leads to the desperate-and false-sense that we need to stay hard
on the brakes as we lean into the corner. In my eight years of instructing
thousands of students of all ability levels on racetracks across the country,
I can tell you without reservation that this panic situation causes more
crashes than all others combined.

When done correctly, trail-braking ("trailing" the brake application as you
enter the corner, making sure to ease off as your lean angle and cornering
force increase) is a very useful tool, but it's one that should be wielded
with caution. Like a razor-sharp knife, the line between success and failure
is pretty thin, and the consequences can be costly. Visit www.
sportrider.com/0703 for a link to more info on trail-braking.

While novice riders typically lose front-tire traction from excessive
trail-braking, they also sometimes transfer too much weight forward by
chopping the throttle (shutting it suddenly) midcorner. In either case, the
sensation of losing front-tire traction is the same: The feedback usually
communicated through the handlebars to your hands goes quiet, similar to the
volume suddenly being turned down on your stereo. The next sensation is that
of the bars turning inward as the contact patch loses traction and the bike
falls inward.

Losing rear-tire traction is most often caused by too much throttle for a
given lean angle. While expert riders have enough skill and experience to
feel and control slides with throttle and lean-angle inputs, novice riders
usually end up losing rear-tire traction suddenly and with little warning.
The problem is that if the rider chops the throttle and the rear tire regains
traction, the energy released from the momentum of the bike and rider's
weight compressing the suspension completely and then springing back with
full force can result in the dreaded highside, where the rider ends up
catapulted high into the air, often with bone-crunching consequences upon
landing.

Ironically, the solution to both situations is throttle application. In the
front-tire situation, smoothly but quickly applying throttle relieves the
load on the front tire by transferring weight to the rear, allowing the front
tire to regain traction. In the rear-tire situation, backing off the throttle
ever so slightly allows the tire to regain traction, while the continued
throttle application maintains rear-tire rotation so that it continues to
propel the bike forward, its gyroscopic effect helping keep the bike upright.
Both these situations, however, happen quickly enough that the techniques
must be done on reflex, and the only way to make such action instinctive is
practice. Obviously, practicing these techniques on the pavement is extremely
difficult (and could lead to expensive repair bills, both from the hospital
and bike shop), so the best way to learn throttle control in these situations
is to practice on the dirt with 125cc or smaller machines, where the
consequences of a mistake are much less costly.

If you do happen to crash, the first thing to do is get away from the bike.
You've probably seen videos of 125 and 250 Grand Prix riders hanging onto the
bars as their bike slides to a halt so that they can pick the bike up and get
back into the race, but getting one of your body parts trapped under the
handlebar or other component is an easy way to lose it. Also, the bike has
some serious kinetic energy built up; not only will it slide much farther
than you, but should it begin tumbling, it will cause you even more serious
injury if you become caught up in it. Try to relax and lay your body out as
straight as possible to keep from tumbling. If you do tumble, you will more
than likely end up violently whacking your appendages against the ground,
often with bone-splintering results. While tumbling is a good way to avoid
injury if you fall while walking or running, the energy built up traveling
even as slowly as 30 mph will cause your arms and legs to fly outward
uncontrollably. Sliding flat on the ground helps you scrub off that speed
much more quickly, without the danger of exposing your limbs to additional
impacts.

Once you are sliding on the ground, you need to resist the temptation to get
up before you've stopped. It's very easy to become disoriented and think that
you are sliding at a walking pace, when in reality you are still traveling at
speed. Should you try to get up before you've stopped, nine times out of 10
you will end up tumbling because your legs will be taken out from under you.
A good practice is to wait until you think you've stopped, then count to
five-then make sure you don't have any major injuries before attempting to
get on your feet.

Finally, the most beneficial thing you can do after a crash is be brutally
honest with yourself about the cause and your possible contributions to it.
It's all too easy to get defensive and, intentionally or not, place the blame
on anyone or anything but yourself. From experience I can tell you that the
riders who say they are never at fault for their crashes end up crashing for
the same reasons again and again.

As an instructor, I've always taken it upon myself to study each crash as
objectively as possible, identify the factors (there are typically several)
and have everyone learn from the mistakes of others-mine included. You can
learn from personal experience as well as that of others. And when it comes
to crashing, I strongly suggest the latter.