Suspension Basics

In this, the first part of Wolfie's tech tips, Wolfie explains the basic principles of a trail bike's suspension.

Bike 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 height 
  • Damping - this controls the springs resistance to being compression and its resistance to rebounding back. 

Spring Setup
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.
suspbasicsrearspring.jpg
The rear spring has a long thread and two "nuts" for adjustment and locking down.

Damping Setup
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.
suspbasicsfrontcompression1.jpg
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.
suspbasicsfrontdampening.jpg
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.
suspbasicsrearcompression1.jpg
Adjustable rear compression.

WHAT'S NEXT?

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...
 

suspbasicsfrontcompression2.jpg
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.
suspbasicsrearcompression2.jpg
A slightly different style rear compression adjustment. Just twist the dial..



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