Mountain Bike Suspension Sag Calculator

Set up your fork and rear shock to the right sag for your riding style.

Rider and Bike Setup
Rider Weight (include gear) 165 lbs
100 lbs280 lbs
Fork Travel 140 mm
80 mm200 mm
Shock Stroke (eye to eye) check shock body or manual
mm
Volume Spacers (rear shock) 0
0 (stock)5
Sag target range
Your setup
Compressed travel
Fork Sag
20%
28 mm of 140 mm travel
55-65 psi starting point
Target: 15-25% (Trail)
Shock Sag
25%
14 mm of 55 mm stroke
130-150 psi starting point
Target: 25-30% (Trail)
Coil Spring Rate Calculator

Spring rate is determined by your weight, the leverage ratio, and your sag target. This gives you a starting spring to try.

450 lb/in
80 N/mm
Nearest stock springs: 450 lb/in (Fox/RockShox) or 450 lb/in (Cane Creek)
Pump-off pressure loss: When you disconnect a shock pump, you lose about 1-2 psi on a fork and 3-5 psi on a rear shock. Set pressure slightly above target to account for this.
Wheel Sag vs Shock Sag Converter

Most manufacturers give sag targets as a percentage of rear wheel travel, not shock stroke. On progressive frames these differ. Enter your numbers to convert.

Wheel travel
mm
÷
Shock stroke
mm
=
Leverage ratio: 2.55:1
For 30% wheel sag, set shock to 12% (6.5 mm)