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Free Tool

MTB SETUP CALCULATOR

Fork pressure, shock pressure, sag targets, and tyre pressure for your mountain bike. Brand-specific data from Fox, RockShox, and more.

Include riding gear (add ~3-5kg / 7-11lbs to body weight).

Pressure varies significantly between brands and models.

Number installed in fork and/or shock. More spacers = more end-stroke progression.

Most modern MTB wheels are 28-32mm internal. Check your wheel manufacturer specs.

Heavier casings (e.g. Maxxis EXO+, Schwalbe Super Gravity) allow lower pressures.

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Quick answer

Enter rider and bike weight, shock type (air or coil), and intended use (XC, trail, enduro, DH). The calculator returns starting fork and shock pressures, sag targets, and a sequence of bracketing adjustments to dial in suspension on the trail.

WHAT IT DOES

Most riders set suspension once and never touch it again — usually too soft on the rear and too stiff on the front. This calculator gives you a sensible starting setup based on your weight and discipline, then walks you through the bracketing steps to fine-tune sag, rebound, and compression.

WHO IT'S FOR

  • →MTB riders new to suspension setup
  • →Cyclists changing bikes, weight, or terrain
  • →Anyone whose bike feels harsh on small bumps but bottoms out on big ones
  • →Trail and enduro riders setting up for a specific course

HOW IT WORKS

Air-spring pressure scales with rider weight and the manufacturer's recommended sag percentage for the discipline (typically 20-25% for XC, 25-30% for trail, 30-35% for enduro/DH). We use known PSI/kg curves for popular Fox and RockShox dampers, plus a sag-bracketing protocol to fine-tune. Coil spring rates use the standard load-deflection equation.

  1. 01

    Weigh yourself in full riding kit

    Helmet, pads, hydration pack, shoes, and water — full ride weight. This number is what the suspension actually has to support.

  2. 02

    Pick discipline and shock type

    XC, trail, enduro, or DH; air spring or coil. Sag targets shift with discipline.

  3. 03

    Set starting pressure or spring rate

    Use the calculator's starting value, then check sag with a sag-meter or O-ring while seated in normal riding position.

  4. 04

    Bracket your settings

    If sag is too high, add 5-10 PSI; too low, drop 5-10 PSI. Adjust rebound to match the suspension's recommended damping curve. Compression last.

  5. 05

    Test on familiar terrain

    Ride a known trail. If the bike packs through repeated hits, increase rebound damping. If it bucks, decrease it. Bottoming on every big drop means add volume spacers, not pressure.

EXAMPLE CALCULATIONS

Trail rider, 80kg in kit, 140mm air fork and shock

  • · Rider weight: 75kg
  • · Bike+kit: 5kg
  • · Discipline: trail
  • · Shock type: air

Fork: ~85 PSI for 25% sag. Shock: ~190 PSI for 28% sag. Rebound 8 clicks from closed front, 7 rear.

Enduro rider, 90kg, coil shock

  • · Rider weight: 84kg
  • · Bike+kit: 6kg
  • · Discipline: enduro
  • · Shock type: coil

Coil spring rate: ~500 lb/in for 30% sag. Air fork: ~95 PSI. Rebound and compression set to mid-range to start, then bracket.

LIMITATIONS

Suspension setup is highly individual and depends on terrain, riding style, and damper internals that differ between models. Use the calculator as a starting point — the bracketing protocol is what actually dials it in. We can't see your specific damper's tune or whether your seals need a service.

When to see a coach

If your suspension still feels wrong after bracketing, the issue is usually a service item — worn seals, contaminated oil, or a damper tune that doesn't match your weight. A qualified suspension service is more effective than another spreadsheet at that point.

FREQUENTLY ASKED QUESTIONS

What is sag in MTB suspension?+

Sag is the amount your suspension compresses under your static body weight in normal riding position. It's measured as a percentage of total travel: 20-25% for XC, 25-30% for trail, 30-35% for enduro and DH. Too little sag means the suspension can't track small bumps; too much means it bottoms out.

How do I set my fork pressure?+

Start with the calculator's recommended PSI for your weight and discipline. Strap a sag-meter or zip-tie to the stanchion, sit on the bike in normal riding position (hands on bars, feet on pedals), and check how much travel you've used. Adjust 5-10 PSI at a time until sag is within range.

Air or coil shock — which is better?+

Air is lighter, more adjustable, and supports a wider weight range — best for XC, trail, and most enduro use. Coil is more sensitive on small bumps, more linear through the stroke, and more durable, but heavier and limited to a single rider weight per spring. DH and aggressive enduro often run coil; cross-country runs air.

Why does my suspension feel harsh on small bumps?+

Usually compression damping is set too high, rebound is too slow (so the suspension hasn't fully extended before the next bump), or air pressure is too high for your weight. Drop pressure 5-10 PSI, open compression, and check sag is in range. If it's still harsh, the seals may need service.

How often should I service MTB suspension?+

Lower-leg service every 50 hours, full damper service every 100-200 hours depending on conditions. Riding in mud, dust, or wet weather shortens intervals. A serviced fork or shock is worth more than a top-end model that's been ridden into the ground without maintenance.

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