Originally Posted by neepuk
1. Springs provide the ride height and are what need to be adjusted or changed to provide correct amount of sag.
Over simplified ...
You only have one perameter - ride hieght
That can be set with any spring - change the preload and you can set the ride heigh where ever you like!
To set the spring constand kg/cm or lbs/inch needs two hights ... and two weights.
Ride height is one of them .. say 20-30% of travel on a dirt bike
The other could be sag with the bike alone .. say 10% of travel .. you set that with the preload and then check the ride height is ok .. if not change the spring rating.
Another way is to look at the amount of travel you are using when riding normal/hard. if You use less than 80% of the availble travel you need softer springs .. no point in having travel if you are not using it! If using more then harder springs.
If the bike squats on wash board - too much rebound damping.
Both the adjustors should adjust high speed, mid speed and low speed. (Speed here refers to the shock travel speed .. not the bike speed!)