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Suspension Set-up: The basics Whether you are a road rider
or a racer correct suspension
setup is the key to fast smooth
riding and consistent lap
times. To get the best out
of your bike it needs to be
set up for the conditions
in which you will be riding.
It is considerably easier
to set the bike up for the
Track as you know what conditions
will be like for the next
hour or so and thus you can
dial in the optimum settings
for the that particular situation.
To what extent you change
your suspension settings will
depend on whether your bike
will also have to cope with
riding on the road. Unlike
Roads Tracks are generally
smooth and grippy. So if you
are only going to use the
bike on the track you have
the luxury of fitting harder
springs and modifying the
fork and shock internals.
If you ride on the road as
well as the track you will
probably want to keep a certain
comfort level and concentrate
on just optimizing the current
equipment With incorrect suspension
setup, tire wear is increased
and handling suffers, which
in turn can result in rider
fatigue. Lap times can be
dramatically slower and in
extreme cases safety can be
compromised. Hopefully the
following guide will help
you dial in your suspension
for faster and safer riding
both on and off the track.
Firstly you will need to check
the Fork and Shock sag: this
is the amount the forks and
rear shock settle under load.
To measure it do the following:
push down on the forks a number
of times to settle them, then
mark the stanchion with a
felt pen or put a cable tie
where the dust seal is sitting.
Next ask some for help to
lift on the bars so the front
wheel is just off the ground
and measure the amount the
forks have traveled down.
This is the static sag (or
unladen sag), This can be
changed by adjusting the spring
preload (more preload = less
sag). Repeat the same process
for the rear, this time measuring
the distance from the wheel
spindle to a fixed point on
the tail. Now you are ready
to begin setting up your suspension.
The key is to do it a little
at a time and make notes as
you go. For road riding start
with the wet track settings
and work from there. Basic
Setup: Check the following
Forks sag 18-22 mm for dry
track, 23-27mm for rain. Shock
sag 8-10mm for dry track,
10-14mm for rain. Check chain
alignment. If not correct,
bike will crab walk and sprocket
wear will be increased. Proper
tire balance and pressure,
starting with 30psi front
and 32psi rear (both dry and
wet). Steering head bearings
and torque specifications
- if too loose, there will
be head shake at high speeds.
Front-end alignment. Check
wheel alignment with triple
clamps. If out of alignment,
fork geometry will be incorrect
and steering will suffer.
Crash damage, check for proper
frame geometry. Stock Suspension
Tuning Limitations Manufacturers
plan on designing a bike that
works moderately well for
a large section of riders
and usages. To accomplish
this as economically as possible,
they use valving with very
small venturis. These are
then matched to a very basic
shim stack which creates a
damping curve for the given
suspension component. At slower
speeds this design can work
moderately well, but at higher
speeds, when the suspension
must react more quickly, the
suspension will not flow enough
oil, and will experience hydraulic
lock. With hydraulic lock,
the fork and/or shock cannot
dampen correctly and handling
suffers. The solution is to
re-valve the active components
to gain a proper damping curve.
It does not matter what components
you have, (Ohlins, Fox, Kayaba,
Showa) matching them to your
intended use and weight will
vastly improve their action.
Furthermore, if you can achieve
the damping curve that is
needed, it does not matter
what brand name is on the
component. Often with stock
components, when you turn
the adjusters full in or out,
you do not notice a difference.
In part, this is due to the
fact that the manufacturer
has put the damping curve
in an area outside of your
ideal range. Also, because
the valves have such small
venturis, the adjuster change
makes very little difference.
After re-valving, the adjusters
will be brought into play,
and when you make an adjustment,
you will be able to notice
that it affects the way the
way the fork or shock performs.
Another problem with stock
suspension is the springs
that are used. Often they
are progressive, increasing
the spring rate with increased
compression distance. This
means that the valving is
correct for only one part
of the spring's travel, all
other is compromise. If the
factory does install a straight-rate
spring, it is rarely the correct
rate for the weight of the
rider with gear. The solution
is to install a straight-rate
spring that matches the valving
for the combined weight of
the bike, rider and gear to
the type of riding intended.
Remember! • Always make small
adjustments, more is not always
better. • Always keep notes
of what you have done. • Suspension
tuning is an art - be patient
Mark Thompson has spent the
last 20 Years Racing motorcycles
and managing Race Teams. He
now runs the Trackbikes website.
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