BMW Z8, Owner'S Manual, Page: 88 / 175

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Antilock Brake System ABS
The concept
ABS enhances active safety by helping
to prevent the wheels from locking
under braking. Why is this important?
When front wheels lock up and cease
to turn, the tires break into a slide.
Result: the driver loses the ability to
steer the vehicle. Traction loss at the
rear wheels can cause the back end of
the vehicle to slip sideways and break
away in uncontrolled oversteer.
With ABS, you will achieve the shortest
possible braking distances under all
given conditions – braking while driving
straight ahead or in curves, different
road surfaces.
ABS is designed to meet two essential
requirements during every brake appli-
cation:
>
To help provide vehicle stability
>
To help retain steering and maneu-
vering capability on all types of road
surfaces, e.g. asphalt, concrete, dirt,
wet surfaces, snow and ice.
Braking with ABS
The system is operative once the
vehicle exceeds a speed of approx.
6 mph/10 km/h. The ABS is deactivated
whenever the vehicle's speed drops
back below approx. 4 mph/6 km/h. This
means that the wheels can lock only in
the final phase of a panic stop – a factor
of no substantive significance in actual
use.
The ABS system works best in situa-
tions requiring maximum pressure on
the pedal – full braking. Since the
vehicle maintains steering responsive-
ness, you can nevertheless avoid pos-
sible obstacles with a minimum of
steering effort.
The ABS system's closed-loop control
circuit cycles in fractions of a second.
A pulsing of the brake pedal, combined
with the sounds associated with the
hydraulic controls, tells you that the
brake system is within its maximum
limit range and reminds you that you
should adapt your vehicle's speed to
road conditions.
On road surfaces that have a loose sur-
face layer on a firm base with good
traction – on gravel, deep sand or snow,
for example – braking distances may be
longer than with locked wheels. This
also applies to driving with snow
chains. However, ABS continues to
provide enhanced vehicle stability and
steering response under these condi-
tions.
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