How to set suspension rebound and compression damping.
Last time we talked about suspension we went over setting sag, Modified Suspension Q&A With Traxxion Dynamics. In this latest segment we will talk about setting the rebound and compression damping. Compression damping helps the suspension absorb bumps or road irregularity as the wheel moves upward in the stroke. Rebound damping helps the suspension return to the proper position, after a bump or other irregularity causes the fork to compress, in a smooth and controlled motion. Too rapid of a movement or too slow of a reaction will cause the bike to handle poorly.
Most places I seem to ride are full of pot holes, rumble strips, and even sink holes. Sadly these are common road hazards we deal with every day. That means your suspension needs different damping rates at different times. The average stock suspension adjusters only deal with low speed damping. This helps with large rolling bumps, braking, and acceleration. Those rough wash board sections that are common after a long winter are controlled by high speed damping, and unless you are running top of the line Öhlins or equivalent you won’t have this adjustment.
A couple pieces of advice before you even start making adjustments. Just like when you set sag you need to find the OEM setting your bike came with. Write this down and you can always go back to it. It is important to test each setting, make small changes and then validate that change. Make changes until the bike starts to handle poorly, then start going back until you find that sweet setting. Check your manual as well, the manufacturers suggestions are excellent places to start your testing.
Don’t be scared of doing this. OEM adjusters can make the ride better but lack the range to make the bike unrideable. Just remember to write down your initial settings and you can always go back. Setting the damping should only be done after you have set sag where you are comfortable.
Depending on how your suspension is setup you may have different adjusters than what I describe. The process is the same but check your manual. All adjusters will have some method of tracking where you are. This might be counting quarter turns from a mark, or from fully tight. I am going to describe a clicker style adjuster.
Turn your adjuster, counting each click, until you reach the stop. Write this number down and don’t lose it. Now turn the adjuster to the setting you looked up in the owners manual. This is where you will start your testing. It may be right where you started and that’s perfectly OK. Your manual will tell you whether clock wise or counter clock wise is the proper direction to check this and make adjustments. Many shocks and forks have the plus and minus on the adjuster to help you.
What should it feel like? Compression damping attempts to keep the wheel from leaving the road when going over a bump. Too soft and the wheel moves too quickly and travels further up in the stroke causing it to leave the road surface. To hard and the energy doesn’t dissipate in the springs and instead travels to the steering head and frame causing the bike to “pop” up and again the wheel leaves the ground.
You will definitely be able to tell how this setting is changing as you test. I will continue to hammer this point. If the new setting doesn’t give you more comfort, confidence, and control, it’s the wrong setting.
Turn your adjuster (IN), counting each click, until you reach the stop. Write this number down and don’t lose it. Now turn the adjuster to the setting you looked up in the owners manual. This is where you will start your testing.
So what should it feel like? When your rebound is set properly the bike will settle quickly after a bump, it won’t continue to bounce, and although you will feel the bump it will be smoother. You want to return the wheel to the road as quickly as possible without causing the chassis to feel unsettled. Remember the goal is comfort, confidence, and control. If the new setting doesn’t improve these you are going the wrong direction.
The most common mistake made by people learning to tune suspension is to use too much rebound damping. “Less is more” is a great rule for setting rebound damping. Too little will result in soft “chatters” of the wheel when it is fully loaded in a turn.
What if it doesn’t get any better? With worn or old components, and limited adjustments on stock parts this can happen. You can do your best to find a compromise that gives you the comfort, confidence, and control you can live with, or you can work with a suspension company to get new parts that will give you the feel you want. The key is to get out there improve your bikes performance and allow you to ride longer with more comfort.
This article was written with help from Max McAllister, owner of Traxxion Dynamics.