General Notes; Antilock Brake System (Abs) - BMW R 12 nineT 2023 Rider's Manual

138 ENGINEERING DETAILS

GENERAL NOTES

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eering, go to:
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ANTILOCK BRAKE SYSTEM
(ABS)
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 foot-
brake lever acts only on the
rear brake.
ATTENTION
Attempted burn-out despite
Integral braking function
Damage to rear brake and
clutch
Do not burn out tyres.
How does ABS work?
The amount of braking force
that can be transferred to the
road depends on factors that
include the coefficient of fric-
tion of the road surface. Loose
stones, ice and snow or a wet
road all have much lower coef-
ficients of friction than a clean
and dry asphalt surface. The
lower the coefficient of friction,
the longer the stopping dis-
tance.
If the rider increases braking
pressure to the extent that
braking force exceeds the max-
imum transferable limit, the
wheels start to lock and the
vehicle loses its directional sta-
bility: A fall is imminent. Before
this situation can occur, ABS
intervenes and adapts brak-
ing pressure to the maximum
transferable braking force. The
wheels continue to turn and the
driving stability is retained irre-
spective of the road condition.
What are the effects of
surface irregularities?
Surface irregularities can cause
the wheels to lose contact tem-
porarily with the road surface.
If this happens the braking
force that can be transmitted
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
surface. At this instant the ABS
must assume an extremely low
coefficient of friction (gravel,
ice, snow), so that the wheels
will continue to rotate under all
imaginable circumstances, be-