Dialling in your mountain bike suspension doesn’t have to be a dark art. Whether you’re new to riding or looking to fine-tune your setup, this mountain bike suspension guide will show you exactly how to set sag, adjust rebound and compression, and tune your fork and shock for your terrain and riding style.
A proper MTB suspension setup transforms how your bike rides. With the right sag, rebound, and compression settings, your bike will track better, feel more controlled, and reduce fatigue on long rides. From air shock setup on trail bikes to understanding coil vs air shock differences on enduro rigs, this guide covers everything you need—no mysticism, just clear steps you can follow at home or at the trailhead.
Get it right and your bike will feel planted, predictable, and fast. Get it wrong and even the best bike will feel harsh, nervous, or vague.
Suspension isn’t about chasing someone else’s numbers. It’s about finding your sweet spot—the balance between support, comfort, and control that matches your body, your bike, and your trails.
Let’s demystify it.
Mountain Bike Suspension Basics: How Forks and Shocks Work
Before touching a single dial, it helps to understand what’s actually going on under you.
Mountain bike suspension is simply how your bike absorbs impacts and returns to shape. At its core, it’s a spring and a damper working together. The spring supports your weight and absorbs bumps. The damper controls how fast that spring compresses and rebounds.
That “spring” comes in two flavours:
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Air suspension – pressurised air in a chamber (most common on modern trail bikes)
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Coil suspension – a mechanical steel spring, favoured on harder-hitting enduro and downhill rigs
On full-suspension mountain bikes, the fork controls the front wheel’s movement and the rear shock manages the back wheel. Together, they determine how your bike tracks the ground, absorbs hits, and stays composed through chaos.
Travel: How Much Suspension Do You Need?
“Travel” is how far your suspension can move as it compresses over terrain—how much up-and-down movement your wheels have.
It’s measured in millimetres, and different bikes use different amounts depending on their job:
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XC & light trail bikes (100–140mm front, up to ~130mm rear)
Fast, efficient, agile. Built for climbing, long rides, and poppy trail fun. -
Mid-travel trail bikes (around 150mm front / 140mm rear)
The do-it-all zone. Enough squish for rough trails, still lively every day. -
Enduro & downhill bikes (160–200mm)
Built to charge. More travel means more margin for error, bigger hits, and gnarlier terrain.
More travel doesn’t automatically mean better—it’s about matching the bike and its setup to what and how you ride.
MTB Suspension Setup: Sag, Rebound, and Compression Explained
Every modern MTB suspension system revolves around three core adjustments:
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Sag – how much travel is used under your body weight
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Rebound – how fast the suspension returns after being compressed
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Compression – how easily the suspension compresses in the first place
Get these in the right ballpark and your bike will feel alive. Miss them and it’ll feel like you’re fighting it all day.
How to Set Sag on a Mountain Bike (Front and Rear)
Sag is your foundation. Everything else builds on it.
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Check the manufacturer’s recommended pressures for your weight.
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Remove the valve cap on the fork and attach a shock pump. Inflate to the suggested pressure.
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Do the same on the rear shock.
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Slide the rubber o-rings down:
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Fork: to the bottom of the stanchion
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Shock: toward the shock body
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Carefully get on the bike in a neutral riding stance. Bounce lightly a few times, then settle. Use a wall or a friend for balance.
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Step off without bouncing and check the o-rings.
As a starting point:
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Trail bikes: 20–25% sag (rear), 15–20% (fork)
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Enduro / DH bikes: 30–35% sag (rear)
If the o-ring hasn’t moved enough, remove air. If it’s gone too far, add air. Repeat until you’re in range—in full riding kit.
This is the single most important step in any mountain bike suspension setup.
Coil vs Air Shock MTB: Which Is Right for You?
Most bikes ship with air shocks because they’re easy to tune with a pump. Coil shocks are gaining popularity for enduro and downhill thanks to their consistency and feel.
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Air shocks
Infinitely adjustable. Light. Versatile. -
Coil shocks
Require the correct spring rate for your weight. Tuning often means swapping springs.
Preload (Coil Only)
Preload adds tension to a coil spring, reducing sag and raising ride height. Most manufacturers limit this to around five turns. If you need more, the spring rate is wrong.
Volume Spacers (Air Only)
These plastic inserts reduce air volume inside the shock or fork, making the suspension more progressive. Perfect if you’re bottoming out despite correct sag.
Mountain Bike Sag: Finding the Right Suspension Balance
Sag determines how soft or firm your bike feels under you. Too little and the bike skitters across roots. Too much and it wallows.
Most riders land between 20–35% depending on bike and discipline. Trail bikes live at the lower end. Enduro and DH creep higher.
Get sag right and your bike becomes:
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More efficient
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More comfortable
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More fun
Everything else becomes easier to tune.
MTB Rebound Settings: What “Too Fast” and “Too Slow” Feel Like
Rebound controls how fast your suspension returns after a hit. It’s adjusted with dials—often marked with a tortoise and hare, “+ / –”, or “fast / slow.”
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Too fast: the bike feels nervous and pingy
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Too slow: the suspension “packs down” and feels dead
Most bikes use a single rebound adjuster. Higher-end models may offer separate high- and low-speed control.
Top tip: For high-speed terrain, try slightly faster rebound to reduce arm pump and keep the bike lively.
Mountain Bike Compression Settings: Low-Speed vs High-Speed
Compression is the flip side of rebound—it controls how easily the suspension compresses.
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Low-speed compression: pedalling, corners, rolling terrain
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High-speed compression: square edges, drops, hard landings
Not every bike offers both, but those that do let you add support without sacrificing plushness.
The goal is balance:
Plush over chatter. Supported in corners. Calm on landings. Never wallowy.
Manufacturer settings are a great start—but your trails are the real test track.