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Suspension & Setup

Static Sag Calculator

Static sag is bike-only, no rider. Too little static sag with correct race sag means the spring is too soft (you used a lot of preload). Too much static sag means the spring is too stiff.

Inputs
Results
Live

  • Static sag

    35mm

  • Typical rear window

    25–40 mm

  • Race sag entered

    102mm

  • Spring read

    Spring rate looks reasonable

Formula

Static sag = extended − bike on the ground

A common MX window is 25–40 mm rear static sag once race sag is set.

Related calculators

Sag
Sag is how far the bike settles from fully extended. Measure from a fender mark to the axle with the bike on a stand, then on the ground.
Race Sag
Race sag (rider sag) is measured with the rider in full gear, balanced on the pegs. Most MX bikes want about 100–108 mm on ~310 mm travel.
Rider Sag
Front and rear rider sag together. Enter fender-to-axle (or a zip-tie on the fork stanchion) for each end.
Spring Rate
Estimate fork and shock spring rates from rider weight, sag targets, and linkage leverage. A starting point for ordering springs — not a replacement for a tuner.