Setting your sag
The first item to address for any good suspension setup is setting preload for static sag. Static sag is the amount your suspension compresses from full extension when you sit on the bike. We've covered how to measure and set sag a number of times (visit www.sportrider.com/0402 or see Ask the Geek, Aug. '03), but a short recap is shown on page 55.
The important measurement for preload is the rear sag setting. For street use, you should aim for 30mm of sag; if you're heading for the track, shoot for 25mm. Choose a value you want for rear sag, and adjust your rear preload accordingly. Write the sag numbers down along with your preload setting.
An actual number for front sag is less important, especially considering that more bikes come from the factory with extra front sag that helps keep the front tire on the ground under acceleration. Knowing that changing preload does not alter spring stiffness, what happens when you turn the adjuster? The starting position of your suspension's travel to a higher or lower point changes. For now, the only reason you will want to change front preload is if your suspension is bottoming-which you can check by wrapping a zip-tie around a fork tube-or if you have too little sag and the fork is topping out-which you will feel as the front end skipping over bumps and losing traction as you exit a turn.
Measure your front sag, and if you have less than 25mm (track) or 30mm (street), adjust your preload to obtain the appropriate value. Otherwise, leave the adjuster as is, or set it to the factory-recommended setting for now. Record all the numbers as well as the preload setting, and we'll come back to it in step four, dialing it in.
Set your rear sag to 25mm...
Set your rear sag to 25mm for the track or 30mm for the street.
Front sag should be no less...
Front sag should be no less than 25mm for the track, 30mm for the street. Some bikes come with extra front sag built in; for now, don't worry if you have too much.
Use a zip-tie on a fork tube...
Use a zip-tie on a fork tube to keep track of how close your suspension is to bottoming.
Controlling your suspension
With nothing to measure, finding a starting point for compression and rebound damping is a much more subjective process. As always, write down your current settings before changing anything.
Find the total range of your compression adjusters by turning them out to the full soft position, then, counting the number of turns or clicks, turn them in until they stop. When dealing with damping adjusters, never crank them tight, otherwise you may damage internal components-just lightly seat them at the end of the range. Back each adjuster out one-half of its full range-for example, if you have 12 clicks of range, set the adjuster to six clicks out.
Turn your rebound adjusters in to the full stiff position and push down on the suspension. Pretty slow coming back up, right? Now back the screws all the way out and try again. You should notice a big difference in the way the fork or shock extends-it may even come up quick enough to top out the suspension and then settle again, much like a car with blown shocks behaves over bumps.
Set the rebound adjusters so that after you forcibly push down on the front or rear of the bike, it does not rise beyond its normal resting point when you let go. The bike should rise to the point where you started in approximately one second with just the force of the springs. If the front or back comes up quickly, overshoots and settles back down to its resting point, add more rebound. If you count more than a second for the bike to come up and stop, take out some rebound. Unsure? Err on the too-stiff side for now. In fact, dial in a couple extra clicks or a half-turn just to be certain.
Set your compression damping...
Set your compression damping adjusters to the midpoint of their range
Rebound damping must be set...
Rebound damping must be set by feel. Push down on the front end and let it rise on its own. It should take approximately one second for it to return to its original position.
Push down on your tailsection...
Push down on your tailsection and let the rear end rise. Again, it should take approximately one second for it to return by itself.