Join Date: Dec 2002
Location: Crittenden, KY USA 41030
Sag on an MX Bike
Sag is important on any bike. On the rear suspension of a dirt bike it should be 35mm difference between the fully extended travel of the suspension (with the rear of the bike suspended above the floor) and the amount of travel remaining after the bike is on the floor. Push the suspension up and down a few time to settle it, then measure it. It the "free sag" is less than 35mm, reduce the preload. If it is more, increase it.
After that setting is correct, sit on the bike with all of your gear on, and in your normal riding position, and have someone measure the amount of travel remaining. There should be 90 - 105mm difference between the free sag and the "laden sag" (with you on the bike).
The forks should have between 25 to 40 mm difference between the free sag and the unladen sag. I have never seen a measurement for the laden sag on the forks.
The final numbers you use will depend on how you ride, how you like the bike to respond, and the terrain you are riding on. You may find that different numbers are needed for different conditions. It is a fair amount of work to change the settings on my KTM, so I use the same ones everywhere.
2003 KTM 525 EXC
Ride hard, life is short