General Instructions; Anti-Lock Brake System; (Abs); Anti-Lock Brake System (Abs) - BMW C 650 GT Rider's Manual

General instructions

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Anti-lock brake system

(ABS)

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
z
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 motorcycle loses
its directional stability. A fall is
imminent. 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
reduces braking force to ensure
that directional stability is main-
tained when the wheels regain
contact with the road surface. At
this instant the BMW Motorrad
ABS assumes an extremely low
https://www.motorcycle-manual.com/
coefficient of friction (gravel, ice,
snow), so that the wheels will
continue to rotate under all ima-
ginable circumstances, because
this is the precondition for ensur-
ing directional stability. As soon
as is registers the actual circum-
stances, the system reacts in-
stantly and adjusts braking force
accordingly to achieve optimum
braking.
Rear wheel lift
Even under severe braking, a
high level of tyre grip can mean
that the front wheel does not
lock up until very late, if at all.
Consequently, ABS does not
intervene until very late, if at
all. Under these circumstances
the rear wheel can lift off the
ground, and the outcome can
be a highsiding situation in which
the Maxi-Scooter can flip over.