However, it's not enough just to have a car with ABS; it is just
as important that you know how to use it to its full potential.
Many people have no understanding of ABS when they buy a car
so-equipped. [In fact, some research has shown more crashes occur
in ABS cars than those not equipped with ABS! - Ed] As its name
implies, ABS will not allow any of the wheels to lock-up, even if
the brake pedal is pushed too hard. This eliminates the "fear
factor" taking over in an emergency and - provided it is used to
its full potential - ABS is a fantastic system for crash
evasion.
Confusion with the use of ABS can however be created when swapping
from a manual system to a car equipped with ABS. As explained
previously, in a manual system it may become necessary to take the
pressure off the brake pedal in order to regain control if wheel
lock-up occurs. In an ABS car it is imperative that pressure is
kept hard on the pedal despite what you may be feeling through the
pedal.
When deployed, the ABS will cause the brake pedal to pulsate or
shudder and usually an audible grinding sound will accompany it.
These sensations have frequently been enough for the uninitiated to
release pedal pressure and have what could have been an avoidable
crash. If you ever get to the point where the ABS cuts in, leave
the pedal pressed firmly where it is - this is as good as it gets!
As the system does not allow wheel lock-up, steering is still
possible - so just select your escape route and steer around the
obstacle if possible.
As with any driving technique, concentration is the key. Give
yourself plenty of room between your car and the car in front - two
seconds is usually enough. This spacing can be easily worked out if
you count slowly when the car in front passes a roadside obstacle.
No matter what your speed, you should be able to count two seconds
before your car passes the same piece of roadside furniture. Look
ahead as far as possible to give yourself the earliest warning of
any impending emergency. And don't fall into the trap of following
the tail lights of the car in front - its driver could be
asleep!
So that's the emergency stop, but what about just good old smooth
retardation on approach to a corner? I guess this becomes more
important to the performance driver but the basics are just the
same - no matter what level you drive at. Judgement and vision,
together with a thorough knowledge of your vehicle's stopping
potential, are key factors in successfully negotiating any
corner.
When pushing the limits, however, sometimes it's just not enough to
be able to stop and turn. In order that you don't risk the chance
of a "compression lock-up", you need to be able to down-change
smoothly while braking hard. Compression lock-up is caused by the
engine spinning at a lower rpm to the drivetrain when selecting a
gear. Anyone who has ever driven a manual gearbox car will have
experienced some form of clutch slip or drag when down-changing.
When the clutch is let out, the drivetrain has to speed up the
engine revs to match, putting an additional braking force through
the driving wheels. If you are hard on the brakes (at the threshold
of lock-up) approaching a corner, a down-change may give enough
additional braking force to lock the drive wheels. To overcome this
problem, a driving technique called heel/toe can be used.
Heel/toe is directly derived from motor racing but it can - and
should - be encouraged for general road driving. Heel/toe is
basically matching the engines revs to the drivetrain revs by
blipping the accelerator with the side of your foot while also
braking and down-changing. A good heel/toe technique starts with
the correct positioning of the ball of your foot toward the
righthand side of the brake pedal. This allows you to pivot
slightly while rolling your foot to the right to allow the
accelerator to be blipped. Pedal positioning in all-important for
this technique to work properly and some cars are better equipped
than others. The blipping should take place just before you let the
clutch out after changing gear. The amount that you blip the
accelerator will depend very much on road speed and can really only
be judged by experience. This technique is difficult to master, but
if you get it right there should be no trace of compression lock-up
and braking should remain smooth and progressive.
Give it a go - not only is it safer and smoother but componentry
such as the clutch plate and the synchros will thank you with a
longer life. Be warned though - it will take lots of practice, and
on your early attempts give yourself plenty of space as you will
probably try to eject yourself through the windscreen!
