Suspension Setup

Suspension SetupIt's been drummed into riders for decades now that suspension sag is critical and must be carefully set.  Unfortunately you've been lied to.  It's all bollocks.

What actually matters is natural frequency, the response of your suspension to your own weight above it.  Frequency is hard to measure, but fortunately we humans have a finely tuned vertical accelerometer.  One that has a big happy place built in which is right around the up and down natural frequency of walking.

Here Are the Basics

Your suspension has springs (air, coil or plastic) front (and maybe rear) which fight gravity, throwing you back upwards after you've pushed down on it.  If the spring is too firm then you'll be thrown back up too fast.  If the spring is too weak then you'll be thrown back up too slowly and softly.  If the spring is just right, it'll feel about right.

Here's What You Do

Wind all the adjusters on your fork and shocks open (fast).  Then go bounce around on the bike on a flat bit of ground (lawn, driveway etc).  Feel how fast the suspension pushes back at you.

If the suspension is too firm (coil too stiff or air pressure too high) then it'll push back too quickly and will feel harsh and jiggly.  Frequency is too fast, spring needs softened.

If the suspension is too soft (coil to weak or air pressure too low) then it'll push back too slowly and will feel soggy and wallowy.  Frequency is too slow, spring needs stiffened.

Keep adjusting air pressure until it feels about right.  There's a decent margin to play with here.  But when it feels right, it is.  More aggressive riders will naturally want a firmer feel and more relaxed riders will want a softer feel.  So it does balance out.

Then balance.  If you have rear suspension then it *must* balance with the front.  Adjust the springs or air pressure until when bouncing on the bike level the rear and front compress evenly, keeping the bike level as the suspension compresses and extends.

Then rebound.  Set it so the suspension extends quickly but smoothly to full extension when either end is lifted.  Too slow will feel dead, too fast will feel unstable.

So What About Sag?

Sag is only a starting guideline.  But it is also a final check as if you're way out then the bike geometry is compromised.  To fine-tune ride-height (sag) while maintaining correct natural frequency requires adjustment of air spring volume or coil spring preload.

Yes.  You've been lied to about volume spacers too.  But more about those here.

Find Out More

For more information about setting up your suspension check out the following articles:

•   Volume Spacers

•   Tuning Rebound Damping

•   Tuning Low Speed Compression (LSC) Damping

   Tuning High Speed Compression (HSC) Damping

   Air Spring Upgrades

   Hydraulic Bottom Out

You may also be interested in our range of Technical Articles & Resources, written to help with bike maintenance.