Sand, rocks, mud? Your dirt bike suspension needs some adjustments to be really dialed for all those different conditions. There are 3 basic rules: Start with standard clicks, never change more than one thing at the time, never change more than 3 clicks in one direction.
"Damping is the dissipation of energy in the case of motorcycles mostly through friction, hydraulic action, spring and air resistance."
I have this sentence out of a suspension book. What it actually means is this: If you hit a rock with 80km/h and you don't want the rock to hit you back just as bad, then you need some damping. Damping includes compression and rebound.
On this site I explain where to find the adjusters compression, rebound and preload and how to operate them. I will also explain how you best can get familiar with your adjusters.
Rebound = forks, shocks are being decompressed (getting longer)
Through damping you can control the speed that your suspension moves in and out.
The third adjuster you will normally find on your suspension is preload.
Preload = The spring preload is the amount (mm) the spring is compressed by the preload adjuster.
Let’s start with the preload. It determines the riding height of your bike. You add preload and your dirt bike suspension will sag less under added weight and therefor the bike will ride higher.
Before changing clicks, your bike MUST be setup correctly with the right spring rates and the rider and static sag in the indicated range!
Otherwise you are wasting your time.
Once you have used the preload adjuster to do the fine tuning of sag and balance you don't need to touch it much for the setup of different conditions and personal preferences.
Not all forks have a preload adjuster but if they do it is usually a big hex adjuster on top of the fork.
The preload on the shock can normally be adjusted by threaded or notched collar on the shock above the spring. As the collar is rotated, the spring is compressed. The more the spring is compressed the higher the preload and vice versa.
Open cartridge forks have compression normally on the bottom and closed cartridge forks have it on the top of the fork leg. If you screw it in (clockwise) you restrict the oil flow in your dirt bike suspension and you will make the compression harder. It will take more force, harder impacts etc. to compress the suspension.
If you screw it out (anti-clockwise) you will make your compression softer. You open the oil transfer passages in your dirt bike suspension, therefor less resistance.
There are systems out there where the adjusters work opposite to this. So to be sure please check your manual. Usually you also have an indicator:
"PLUS" = more damping or harder compression (normally clockwise)
"MINUS" = less damping or softer compression (normally anti-clockwise)
As a general rue the compression adjusters are on top of the shock reservoir. If your compression adjuster has a screw and a hex nut then you are lucky because you can change the low speed (the screw) and the high speed (hex) compression.
If you only have the screw adjuster then you can only adjust the low speed compression. Don't worry - the low speed has some effect on the overall damping. So it is not too bad if the high speed adjuster is missing.
Low speed damping is when the wheel moves up and down slow like a series of wide whoops or the action from the G force of the bike in the turn. Also going through a dip or sandy conditions will move the suspension in and out slowly. In any case it has nothing to do with how fast or slow you ride!
High speed damping is when your dirt bike suspension moves up and down fast. An example for this is landing from a jump or hitting a rock.
Usually open cartridge forks have the rebound on the bottom of the fork leg and closed cartridge forks have it on top. But as usual: if in doubt refer to your manual.
"PLUS" or clockwise makes the rebound slower
"MINUS" or anti-clockwise makes the rebound faster
So rebound is the speed at which the dirt bike suspension extends. The effects of the rebound on the handling are difficult to understand. That's why it is advisable to leave the rebound close to standard clicks most of the time.
1) You obviously first have to check them out on your bike. Do you know where the rebound and compression adjusters are? Do you have a high speed compression adjuster on your shock? Have you got a preload adjuster on your fork?
2) Once you know where they are set your compression and rebound adjusters to standard clicks. Standard clicks are a good starting point and good reference point to keep in mind. It is practical to put a sticker on your bike with your standard clicks, so you can always go back to standard when lost.
If you cannot find out what your standard settings on your dirt bike suspension are then you can count how many clicks you have in total and set them at about 2/3 open (or out, anti-clockwise) as a starting point.
3) Go riding and get a feel for the different adjusters. It is not easy to feel that especially if you don't know what you are looking for. Normally you shouldn't change more than one adjuster at the time and not more than 3 clicks in one direction. But in order to get a feel you can close one adjuster fully, ride a bit and then open it fully to get the contrast.
My husband was a suspension technician at KTM Austria and they often went suspension testing with the top riders like Giovanni Sala or the German MX Champion. Sometimes they would throw a curve ball and just pretend to change something and send the rider out again. Not many riders would come back with the exact feedback. It is not easy to feel fine differences in the dirt bike suspension so take some time to play around and get the feel of it. If in doubt go back to standard clicks!
The Dirt Bike Garage Manual
HOW TO GUIDE for "do it yourself" riders