79
SuSpenSion
GLoSSARY
Spring rate or hardness:
The force that is required to compress the spring by a certain spring
travel – measured in newtons per millimetre (N/mm) or pound per inch
(lbs/in). A higher spring rate requires more force for the travel. In pneu-
matic spring elements this corresponds to a higher pressure.
Spring preload:
Coil springs and elastomers can be pretensioned within a certain range.
Then the suspension only reacts when a greater load is applied. How-
ever, the spring rates are not changed as a result. Heavy riders cannot
compensate for springs that are too soft through a greater degree of
pretensioning.
negative spring travel (“sag”):
The spring travel that is taken up by the rear structure or the fork when
the rider takes up his or her usual riding position at a standstill. This is
usually specified as a percentage of the overall spring travel
(b)
.
compression damping:
Delays or brakes the initial compression. In especially high-quality
spring elements this is split into “High Speed” (for hard impacts = rapid
spring compression) and “Low Speed” (for slow compression, for ex-
ample, when riding out of the saddle) compression damping.
rebound damping
(c)
:
Delays or brakes the rebound.
lockout
(d)
:
A device to block the fork or the rear shock so that the spring element
does not cause bob when riding on tarred roads or smooth surfaces.
Not to be used off road.
platform damping:
Increases the (“Low Speed”) compression damping rate and sup-
presses bob. As opposed to the lockout function, the suspension is not
blocked completely.
SUSPENSIoN FoRKS
Most WHEELER mountain bikes and many pedelecs are equipped with
suspension forks
(e+f)
. This feature gives you better control of your
WHEELER bicycle when riding cross-country or on rough road surfaces
and ensures more ground contact for the tyre. It noticeably reduces the
strain on you and your bicycle caused by the mechanical shocks from
the terrain.
Suspension forks
differ in their types of spring elements and damp-
ing. The suspension is usually provided by coil springs, special types
of plastic (elastomers) or sealed air compartments, or combinations of
these options. The damping is usually done by oil or by the self-damp-
ing properties of the elastomers.
I
Suspension fork manufacturers normally include instruc-
tions with their deliveries. Read them carefully before
changing any settings or doing any maintenance work on
your suspension fork. You can find the instruction of the
suspension fork manufacturer on the enclosed CD.
i
For more information see the suspension glossary heading
this chapter.
Adjusting the Spring Rate
To work perfectly, the fork has to be adjusted to the weight of the rider,
the sitting posture and the intended use. The suspension forks should
yield by about 10-25 % of their total travel under the rider’s weight
(g)
.
Be sure to have this adjustment carried out by your WHEELER bicycle
dealer at the time of delivery.
Note in general that the suspension fork must give in a little even when
you are just sitting on the WHEELER bicycle – this is the so-called
negative spring travel or sag. If you ride over a pothole the spring is de-
compressed and the suspension fork compensates for the unevenness.
If the air pressure or the spring preload are too high, this effect is lost
because the suspension forks is already fully extended. This means that
an important comfort and safety factor is lost if the tyre briefly loses
contact with the ground.
The suspension fork should yield by about 10-25 % of its total travel
under the rider’s weight.
Attach a cable tie around one of the stanchion tubes
(h)
and pull it tight
enough so that it can still be moved but does not move by itself.
a
b
c
d
78
e
f
g
h
Summary of Contents for Cross
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