In this, the first part of Wolfie's tech tips, Wolfie explains the basic
principles of a trail bike's suspension.
All off road motor cycles have complex suspension systems. Unlike your
family car, the bikes suspension is fully adjustable. To understand how
a bike's supension works (or more importantly why) we first must understand
the 2 basic principles of suspension:
Springs - these enable the suspension to return to the pre set suspension
Damping - this controls the springs resistance to being compression and
its resistance to rebounding back.
|When setting up suspension always start with the spring
first. The front and rear suspension must have about 5cm of free play and
they both must be even!!! "5cm of free play" means that the bike can be
lifted 5cm before the wheels leave the ground. This setting enables the
bike to stay in contact with the track on light to medium bumps, keeping
us in control.
The rear spring has a long thread and two "nuts" for adjustment
and locking down.
|Start with compression damping at the front end. Compression
damping is made harder or softer by adjusting screws on the top of the
forks. Both sides must be evenly adjusted.
To start with, turn both the screws clockwise until they stop turning
(do not force them, they are delicate). Now turn the screws counterclockwise,
counting the clicks until they then again stop turning. As a basic setting
pu them in the half way position, for example, if there is 30 "clicks"
total then set both legs on 15 clicks.
Adjustable front compression.
|Repeat this operation for the rebound damping. This is adjusted
on the bottom of the fork. Note that there will be a rubber grommit protecting
the screws that will need to be removed.
Adjustable front dampening.
|The rear should be set the same way, there is only one adjusting
screw for the compression damping. Set the rebound the same way, count
the clicks, select the half the total number of clicks.
Adjustable rear compression.
The bike is now basically set up. It might be now perfect for someone in
the world, but we are all different weights, heights and have different
styles. The next step is to tune in to the player...
Conventional forks sometimes use an air pressure style compression
system. Put a tiny bit of air (3-5psi) in with a hand pump to make it harder,
remove air to make it softer.
A slightly different style rear compression adjustment. Just twist
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