Brake System With Bmw; Motorrad Abs - BMW C 650 GT Rider's Manual

Brake system with
6
BMW Motorrad ABS
66
How does ABS work?
The amount of braking force that
can be transferred to the road
depends on factors hat 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-
z
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
regain contact with the road sur-
face. At this instant the BMW
Motorrad ABS must assume an
extremely low coefficient of fric-
tion, so that the wheels will con-
tinue to rotate under all imagin-
able circumstances, because this
is the precondition for ensuring
directional stability. As soon as
http://www.motorcycle.in.th
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 Scooter can flip over.
Severe braking can cause
the rear wheel to lift off the
ground.
When you brake, bear in mind
that ABS control cannot always
be relied on to prevent the rear
wheel from lifting clear of the
ground.