How to adjust your suspension fork and shock

By Christian Jensen - 22.03.2026

If you’ve just bought a new bike and want to set it up properly, or if you’ve ever wondered what that mysterious dial on your fork actually does? This guide is for you. Here, I’ll walk you through the basics of adjusting most modern suspension forks and rear shocks. This article focuses on air suspension, since coil‑spring systems use different adjustment methods. Cheaper coil forks often have nothing more than a simple spring inside the stanchion, while high‑end coil shocks are typically bought by riders who already know exactly what they want. So for now, we’ll stick to air suspension.

Air pressure: The foundation of all suspension setup

Regardless of how advanced or expensive your suspension is, every air fork and shock must allow you to add air. You’ll find a cap covering a Schrader valve on one of the fork legs or at the end of the rear shock. Air pressure requirements vary widely between models, and rear shocks in particular often have special filling procedures.

For example, Fox rear shocks with a negative air chamber must be filled in small increments, no more than 25 PSI at a time, and then compressed to equalize pressure between the positive and negative chambers. Skipping this step can lead to incorrect readings and poor performance.

Setting sag: The most important measurement

Depending on the type of terrain you ride, manufacturers typically recommend 10–30% sag. Sag is the amount your suspension compresses when you stand in a neutral, ready‑to‑ride position on the bike.

Measuring sag is simple:

Use the rubber o‑ring on the fork stanchion or shock shaft
Slide it down to the dust seal
Carefully get on the bike in your attack position
Step off and measure how far the o‑ring has moved

If your suspension doesn’t have an o‑ring, a zip‑tie works just as well.

Add or remove air until you reach the desired sag. This isn’t an exact science and personally, I find 30% too soft for a bike meant to climb and descend. I usually aim for 20–25%.

Rebound: Controlling how fast the suspension returns

Once SAG is set, you can move on to the two other essential adjustments: rebound and compression.

Rebound controls how quickly the fork or shock returns after being compressed.

RockShox uses a turtle → rabbit scale
Fox typically uses plus/minus symbols

It’s easy to assume that faster rebound is always better, but that’s not the case. If rebound is too fast, you may experience what riders call a “mule kick.” You drop off a ledge, the suspension compresses, and then snaps back so quickly that it kicks the saddle into you. Not pleasant.

Most manufacturers recommend starting in the middle of the adjustment range and fine‑tuning from there.

Compression: Controlling how easily the suspension compresses

Compression adjustment is essentially a flow restrictor. The more you close it, the harder it becomes to compress the suspension and the slower it returns to full extension.

Different brands use different systems:

Fox often uses a three‑position lever combined with an Open Mode Adjust dial
RockShox typically uses a Low‑Speed Compression (LSC) dial located near the lockout mechanism

Compression adjustment controls how the suspension behaves under load. A simple way to visualize it is to imagine squeezing a water bottle:

Open the small drinking nozzle → a thin stream comes out
Remove the entire cap → everything gushes out at once

The main purpose of compression adjustment is to quickly switch the suspension into a firmer mode for climbing or smooth terrain. Many systems also allow fine‑tuning within each mode.

Putting it all together

These three adjustments, air pressure (sag), rebound, and compression, form the core of suspension setup. My recommendation is simple:

Set the correct air pressure first
Place rebound and compression in the middle of their ranges
Ride, experiment, and adjust gradually

If you want a shortcut, you can borrow a ShockWiz, a digital tuning tool that analyzes your suspension performance and suggests settings. It’s expensive and not strictly necessary, but it does speed up the process of finding a great setup.

Enjoy the ride!