A mountain bike with bad suspension setup will make a great bike feel mediocre and a mediocre bike feel broken. The dials on your fork and shock are not decorative. Each one changes how the bike behaves under load, and most of the time the wrong setting is doing more damage to your ride than the wrong tire pressure or the wrong saddle height.
This is a complete guide to setting up your mountain bike suspension from scratch. It covers how the parts actually work, the order to set them in, what each dial does, and the small details that separate a bike that feels alive from one that fights you in every corner.
How mountain bike suspension actually works
Every fork and rear shock does two things: it stores energy on the way down and releases it on the way back up. The spring stores energy. The damper controls how fast it gets stored and released.
The spring is either an air chamber or a steel coil. Air springs are adjustable with a shock pump and lighter on the bike. Coils are heavier, harder to fine-tune, and feel more linear because the spring rate stays roughly constant through travel. The choice between air vs coil shocks depends on bike, weight, and what you actually do with the bike.
The damper is a small piston pushing oil through narrow ports. The size of those ports determines how fast oil can flow, which determines how fast your fork or shock can compress and rebound. The clickers on your fork and shock change those port sizes. A click in either direction is a different damping rate.
Two key principles fall out of that:
- Spring controls where in the travel the bike sits. That is sag and overall support.
- Damper controls how fast the bike moves through travel. That is compression and rebound.
Almost every suspension complaint maps to one of those two systems being wrong. The hard part is knowing which.
The setup order matters
People skip around. They turn rebound knobs because the bike feels harsh, they add air because it feels soft, they add a token because it feels too progressive, and three rides later nothing makes sense. There is a right sequence:
- Sag. Set the spring first. Damping does not behave correctly if the spring is wrong, because the damper is starting from the wrong position in travel.
- Rebound. Set rebound second. It is the dial that ties everything else together and influences how the bike feels in every other test.
- Compression. Tune compression after sag and rebound are dialed. Most modern forks have separate high-speed and low-speed compression for a reason, and they do different things.
- Volume tokens. Add or remove volume spacers last, only if you cannot get the bottom-out support you need from pressure alone, or if the bike is too progressive and you are not using full travel.
Doing this order in reverse is the most common reason a bike feels worse after a "tune-up." Tokens change what pressure does. Compression depends on rebound. Rebound depends on sag. Build from the foundation up.
Step 1: Sag
Sag is how much your suspension compresses under your static weight in riding position. It is the cheapest and biggest win in suspension setup. The full breakdown lives in how to set sag, but the short version:
- Use the o-ring on your stanchion or shock shaft.
- Stand on the pedals in your normal riding stance, in full kit, braced against a wall.
- Settle without bouncing. Step off carefully.
- Measure where the o-ring ended up. Divide by total travel to get the percentage.
Aim for 20–25% on the fork and 25–30% on the shock. The lower end of those ranges is for cross-country and short-travel trail bikes. The upper end is for enduro and bikes you actually ride hard on rough terrain.
If you are wondering why these specific numbers, the 30% sag rule explains where the convention came from and when it does not apply.
Step 2: Rebound
Rebound damping controls how fast the suspension extends after compressing. Too fast and the bike kicks back at you over chatter, bounces off rocks, and feels skittish in corners. Too slow and the suspension cannot recover before the next bump arrives, so the bike packs down through travel and rides progressively lower as you go through a rough section.
There is a quick test for rebound on the fork. Push the bars down hard at the front of your driveway and let go. The fork should rebound to full extension, slightly overshoot, and settle in one motion. If it bounces twice, rebound is too fast. If it crawls back like it is in molasses, too slow.
Most riders run rebound too slow. The fix is usually two or three clicks faster than where you started. The full method, including the same test for the rear shock, is in the rebound damping guide.
Set rebound and ride a familiar trail before touching anything else. The temptation to start playing with compression in the parking lot is the single biggest waste of time in suspension setup.
Step 3: Compression
Compression damping controls how fast the suspension can compress under load. There are usually two adjustments on a higher-end fork or shock:
- Low-speed compression (LSC): affects slow shaft movements like rider weight transfer in corners, braking, and pumping the bike. Add LSC to make the bike feel more supportive in turns. Take it away if the bike feels harsh on small chatter.
- High-speed compression (HSC): affects fast shaft movements like square-edge hits and big landings. Add HSC if the fork dives too deep on G-outs. Take it away if the bike kicks on sharp roots and rock impacts.
The two are independent and do different jobs. The biggest setup mistake here is cranking LSC because the bike feels soft, when the actual problem is sag. The second biggest is opening HSC trying to chase a comfortable ride and then complaining the fork bottoms out on every drop.
The full mental model for compression damping, including high-speed vs low-speed, is its own article. Once sag and rebound are dialed, compression is what makes the bike feel like yours.
Step 4: Volume tokens
Volume spacers, sometimes called tokens, are small plastic spacers that take up volume in the air chamber. Less air volume means the spring ramps up faster as you compress, which makes the bike feel more progressive and harder to bottom out.
Tokens are a tool for one specific problem: you cannot get bottom-out support without making the early travel too firm. Add a token, drop pressure 5 psi, and you keep early-travel suppleness while gaining mid-to-late travel support.
The reverse problem also exists. If you never use full travel even on big hits, you might have one too many tokens. Pull one out, add 5 psi, and the bike will feel more linear and use more of its travel.
The detailed call on volume spacers and tokens is its own piece, but the rule of thumb: do not touch them until pressure adjustment alone is not getting you where you want to go.
What rider weight changes
Every recommendation on a fork leg is for some hypothetical 175-pound rider in a t-shirt. If you are 140 pounds in a hydration pack or 220 with body armor, the chart on the leg is wrong for you.
Rider weight affects suspension setup at every level: pressure, damping, spring rate on coils, and the choice of how many tokens to run. Heavier riders generally need more pressure, often want a little more compression, and tend to benefit from at least one volume token. Lighter riders frequently end up running far less rebound damping than the chart suggests.
The good news is once you understand the relationships, you can predict roughly what to change when something about you changes. New body armor for park days? Bump the pressure 5 psi and recheck sag. Lost ten pounds over a winter? Recheck everything.
Common setup mistakes
A short list of the things that come up most often:
- Setting sag in pajamas instead of full riding kit. A loaded pack and pads can move shock sag by 5%. Always set sag in what you ride in.
- Adjusting compression to fix harshness when the real problem is rebound. A bike that hammers your hands on rough sections usually has too-slow rebound, not too-much compression.
- Adding tokens to fix wallowing. Tokens fix bottom-out, not mid-stroke softness. Mid-stroke is a sag and LSC problem.
- Tuning the fork and ignoring the shock. A balanced bike has fork and shock cooperating. If your shock is way under-sprung relative to the fork, the bike will dive in steep stuff and the fork will feel like it is doing all the work.
- Tuning by parking lot feel instead of trail feel. A bike feels different sitting still in your driveway than it does at speed on rocks. Set baseline numbers, then ride and adjust.
When to recheck and re-tune
Suspension setup is not one-and-done. A few markers for when to recheck everything:
- After every fork or shock service. Damper rebuilds change behavior slightly even when done perfectly. The fork service intervals guide explains when those services come due.
- After a meaningful weight change.
- After a new pack, new pads, new shoes, or any other meaningful kit change.
- The first ride of the season after the bike has sat all winter.
- Any time the bike starts feeling wrong and you cannot pin it on a tire or a brake.
If your bike has started feeling worse over time and you cannot remember the last service, run through the warning signs that your suspension needs service. Damping degrades slowly and you will not notice it on a single ride, but the difference between a freshly serviced fork and one that is 200 hours overdue is dramatic.
Reading the bike
The hardest part of suspension setup is not the dials. It is learning to translate the way the bike feels into the change you need to make. Riders describe the same problem with different words, and the same word can mean two different problems.
There is a whole article on reading suspension symptoms that maps complaints like "harsh on chatter," "blowing through travel," and "wallows in corners" to the actual dials. It is the reference to come back to once your baseline is set, when something about the bike starts bothering you and you need to figure out which lever to pull.
For most riders, getting the basics right is the work. Sag, rebound, compression, in that order, with a sanity check on volume tokens at the end. That is 80% of suspension performance. The last 20% is fine-tuning over hundreds of rides as you start to recognize the difference between a bike that is close and a bike that is dialed.
Where to start
If you are setting up a new bike or coming back after a service, start with how to set sag. Once that is right, move to rebound damping. Then compression. Save volume tokens for the very end, and only if you need them.
A dialed bike disappears underneath you. You stop thinking about the suspension and start thinking about the trail. That is the goal.