Proper ABS does a rather more sophisticated process than just pumping
the brakes for you 7 - 10 times per second.
Sensors on the wheel detect the moment that the wheel stops rotating
(i.e. commences to skid, and then release the brakes so that the wheel
rotates and grips the road again. This cycle is repeated extremely
rapidly, with the main benefit being that front wheels retain grip,
and most importantly, you retain steering control.
I have been on one of those "Drive and Survive" courses which include
a track training session with cars where ABS was switchable (by the
instructor) At first it took me quite a while to get out of a 30 year
habit of (a) cadence braking when braking hard from 90 mph, (b) not
attempting to swerve at the same time as braking hard. In practice
you stamp on the brake pedal as hard as you can and steer around those
traffic cones!
BUT we were advised to be very careful with ABS on continuos snow or
ice surfaces. Better switch it of if this is an option. Friction with
the road is so low that the wheels lock and the brakes release,
instantly, and before the vehicle has slowed at all! This is simply
repeated rapidly and overall braking distances are increased
considerably as the ABS basically keeps the brakes in the released
state all the time. Without the "snow wedge" that Daniel mentioned you
just keep going!
My "Padded Cell" has ABS which is brilliant in emergency on tarmac,
but loses the "feel" of brakes on very slippery surfaces.
Oh, on mixed surfaces, where one wheel might be on ice whilst another
is onto tarmac, then the seperate sensors and brake pressure for each
wheel is a real bonus.
Sorry for long lecture!
Have a great Spritely weekend!
Guy
|