How to Set Up Mountain Bike Suspension — Sag, Rebound, Compression
Buying a bike with good suspension is half the job. The other half is setting it up for you. Factory settings rarely match your weight and riding style — a few minutes of adjustment changes how the bike handles entirely.
Sag — your starting point
Sag is the percentage of suspension travel that compresses under your weight (in full riding gear, with a pack if you use one). It's the most important parameter — everything else builds from it.
| Riding style | Front sag | Rear sag |
|---|---|---|
| Cross-country (XC) | 15–20% | 20–25% |
| Trail / all-mountain | 20–25% | 25–30% |
| Enduro / DH | 25–30% | 30–35% |
How do you measure sag?
- Set the suspension to its full open range (all dials in "open" position).
- Push the o-ring on the stanchion all the way down.
- Sit on the bike in your natural riding position — feet on the pedals, hands on the bars. Have someone hold the bike steady.
- Carefully step off without bouncing the bike.
- Measure how far the o-ring moved. Divide by total travel — that's your sag percentage.
You adjust sag with air pressure (air shocks) or spring rate (coil shocks).
Rebound
Rebound controls how quickly the suspension returns to its starting position after a hit. The dial is usually red, marked with a turtle (slower) and a rabbit (faster).
- Too-fast rebound — the bike "bucks" over bumps, losing traction.
- Too-slow rebound — the suspension can't keep up with consecutive hits, "packs down," and loses travel.
Quick test: ride off a curb. The bike should bounce once and settle. If it keeps bouncing, slow the rebound down. If the suspension feels sluggish coming back, speed it up.
Compression
Compression controls resistance as the suspension compresses. It splits into two categories:
- Low-speed compression (LSC) — affects behavior during slow movements: pedal bob, cornering lean. Adding LSC reduces wallowing.
- High-speed compression (HSC) — affects behavior during fast hits: rocks, roots, drops. Adding HSC firms the suspension up for big impacts.
Cheaper suspension has a single compression dial (or just a lockout). More expensive units separate LSC and HSC.
Lockout — when to use it
Lockout stiffens the suspension — useful on long, smooth climbs where bob eats energy. Unlock it for descents and technical terrain, always.
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