Shock Spring Rate Calculator

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 (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.

Front and rear rider sag together. Enter fender-to-axle (or a zip-tie on the fork stanchion) for each end.

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.