58
b
c
d
a
The rear shock should be set up and adjusted in such a way
that it does not reach the end of its travel (known as bottom
out). A spring rate which is too soft (or too low an air pressure)
can usually be heard or felt as a “clunk” type noise. This noise
is caused by the sudden complete compression of the rear
shock as it reaches bottom out. If the rear shock frequently
reaches bottom out, it will become damaged over time, and so
will the frame.
Rear shocks are mounted on full-suspension frames
(a)
in a
way that they absorb shocks from the terrain. If the damper is
too rigid and jammed, the terrain induced shocks pass directly
into the frame without any damping. The frame is normally
not designed to withstand such undamped stresses. If your
bicycle is equipped with a rear shock including lockout
(b)
, you
must therefore keep in mind not to activate the lockout func-
tion when riding over rough terrain, but only when riding over
smooth terrain (tarred roads, smooth tracks).
9.3.3 Adjusting the Damping control.
The damping is adjusted by valves inside. These valves are designed to
modify the flow rate of the oil and hence the speed with which the rear
swing arm moves in and out. In this way it is possible to optimise the
bicycle’s reaction to obstacles. Furthermore, any oscillatory movement
of the rear frame while pedalling can be reduced. For long uphill rides
involving hard pedalling in sitting it is advisable to eliminate the damp-
ing. For this purpose some rear shock models are fitted with a lockout
device. For downhill rides on uneven ground the lockout mechanism
must not be activated.
Rear shocks with adjustable damping are fitted with an adjusting knob
that is (mainly) red to slow down or accelerate the rebound movement
(c+d)
. The second knob, if available, is to adjust the speed of the com-
pression movement.
The adjusting process changes the flow rate of the oil contained within
the suspension fork as it passes through valves and chambers internally.
Some models provide for separate adjustment of compression and
rebound damping. Experience has shown that it is best to begin with the
compression stage entirely open and to first adjust the rebound stage.
Adjusting the suspension fork is a delicate job, as even a small change
on the adjuster can have a big effect. Try approaching the exact setting
you need in increments no larger than a quarter turn from the “Open”-
position.
Rebound is considered satisfactory when the rear frame cycles once
after descending from a high kerb. If you turn the knob too far, the oil
inside will flow very slowly and the rebound will be at maximum. This
will result in a sluggish rebound movement, and the rear shock will not
recover when exposed to a quick series of impacts.
