| Dealing
with hard braking skids:
Steer straight or as straight as possible instantly when a skid begins.
Turned steering encourages brake locking and tends to throw you off course.
In the fastest possible stop, wheels do not lock at any time but are held
at the point of locking throughout. The retarding effect utterly depends
on tyre grip against the surface. The constant supply of fresh tread maintained
by keeping the wheel rolling is what matters.
When a wheel locks, one small pad of tread has all the work to do and
no hope of retarding as effectively. This tiny area of tread abruptly
finds itself scraping along the abrasive surface leaving a trail of skid
rubber. It heats rapidly and may even start to melt. On wet roads it may
simply aquaplane instead.
To apply precisely the hardest possible pedal pressure that will still
not lock the brake requires practice. In an emergency, press the pedal
firmly (if need rapidly increasing the pressure till quite hard) to the
point where a wheel does lock, instantly easing a fraction when this happens,
so as to unlock. Equally instantaneously, for a locked wheel generally
releases within a split second of your easing, back on with resolute pressure
to the lock point ready to ease - only ease - coming back with firm pressure
the same as before the instant it unlocks again. By repeating this procedure
you strive towards the ideal that will stop you the fastest, holding the
brakes at the point of locking throughout.
Partly because speed is dropping all the time the tyre tread can cope
with progressively harsher pedal pressures without locking. Your pedal
push squeezing the brake linings against the wheel drums or discs can
increase as speed drops to a halt. Your repeated on, ease - and instantly
on again process, to ensure your brake is as near as possible to locking
point at every stage, makes certain you apply this mounting pressure as
a stop is reached.
If you lock the brakes for too long the car may begin to spin. Once she
starts to turn - your warning - the dramatic abruptness with which you
can find yourself spinning more, going backwards, or crashing, is terrifying.
Steer straight as far as possible. Directional stability returns mostly
during the seconds brake pressure is eased but you must drive to straighten
immediately and continue to correct as necessary.
When you feel the back beginning to slide to one side or the other you
must steer the same way; steer into the turn, left if the back slides
left, right if right; you must ease the brakes too, to help stop the back
sliding.
In rare circumstances you are desperately trying to stop but control disappears
from the front of the car. No responses come from the steering and easing
the brake does not seem to unlock the wheels. This could be due to greasiness
or due to wet roads and you could be experiencing locked brake aquaplaning.
Until this situation rights itself there is usually little you can do
except keep trying. However, a sharp hard-on handbrake jab sometimes induces
the back to slide or in some way slightly alters the balance of the car
and steering control returns. Instant handbrake release then allows you
to steer to safety and braking can be gingerly resumed.
Till now we have looked mainly at theory. But what happens when you are
faced with piling into traffic?
If there is a clear pavement, or room to the right without head-on danger,
steer for it! You might have to ease braking substantially initially to
get the steering response required. Next hoot. Stopped traffic might realise
and may move forward; anyway it warns them to expect you and they may
avert neck damage by holding their hands round the back of their heads.
A skilled driver is continually planning during traffic conditions where
sudden stops are likely as to escape routes in adverse situations. His
mind subconsciously works on this and in case an adverse situation arises
has an escape route already planned and figured out.
That's it for this month. In the next month we shall delve into various
the over-acceleration skid and 4-wheel drift. Till then strap up and drive
safely. |