General Instructions; Anti-Lock Brake System - BMW S 1000 XR Rider's Manual

General instructions

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Anti-lock brake system

Partially integral brakes
Your motorcycle is equipped with
partially integral brakes. Both
front and rear brakes are applied
when you pull the handbrake
lever. The footbrake lever acts
only on the rear brake.
ATTENTION
z
The integral braking func-
tion makes it very difficult to
spin the rear wheel by open-
ing the throttle with the front
brake applied to keep the
motorcycle stationary (burn-
out).
Attempted burn-outs can res-
ult in damage to the rear brake
and the clutch. Integral pressure
build-up is supported even when
the ABS is switched off.
Do not attempt a burn-out.
How does ABS work?
The amount of braking force that
can be transferred to the road
depends on factors that include
the coefficient of friction of the
road surface. Loose stones, ice
and snow or a wet road all have
much lower coefficients of friction
than a clean, dry asphalt surface.
The lower the coefficient of fric-
tion, the longer the braking dis-
tance.
If the rider increases braking
pressure to the extent that brak-
ing force exceeds the maximum
transferable limit, the wheels start
to lock and the vehicle loses its
directional stability; a fall is im-
minent. Before this situation
can occur, ABS intervenes and
adapts braking pressure to the
maximum transferable braking
force, so the wheels continue
to turn and directional stability
is maintained irrespective of the
condition of the road surface.
What are the effects of
surface irregularities?
Humps and surface irregularit-
ies can cause the wheels to lose
contact temporarily with the road
surface; if this happens the brak-
ing force that can be transmit-
ted to the road can drop to zero.
If the brakes are applied under
these circumstances the ABS
has to reduce braking force to
ensure that directional stability is
maintained when the wheels re-
gain contact with the road sur-
face. At this instant the ABS
must assume an extremely low
coefficient of friction, so that the
wheels will continue to rotate un-
der all imaginable circumstances,
because this is the precondition