Cheat sheet

Spring rate & ride frequency

The spring label is only the starting point. Wheel rate = spring rate × motion ratio², then sprung corner mass turns wheel rate into ride frequency. This sheet uses spring travel divided by wheel travel for motion ratio.

What motion ratio does to a 70 N/mm spring (300 kg sprung corner mass)
Motion ratioRate reaching wheelWheel rateRide frequency
1.00100%70.0 N/mm2.43 Hz
0.9081%56.7 N/mm2.19 Hz
0.8064%44.8 N/mm1.94 Hz
0.7049%34.3 N/mm1.70 Hz
0.6036%25.2 N/mm1.46 Hz

Every wheel-rate and frequency result above is produced by the live spring-rate calculator. Because the ratio is squared, a 0.70 installation delivers only 49% of the spring label at the wheel.

Ride-frequency interpretation
FrequencyTypical useRead it as
Below 1.0 Hzvery soft / comfort-biasedlarge body movement; travel matters
1.0–1.5 Hzroadcomposed, with useful compliance
1.5–2.0 Hzfast road / dual purposeresponsive; clear ride trade-off
2.0–2.5 Hzsmooth-circuit trackbusy on broken surfaces
Above 2.5 Hzrace / aerospecialist platform control

Comparison ranges, not prescriptions. Dampers, tyres, bump stops, travel, road surface and aero load decide whether a target works. Many road setups place the rear roughly 5–15% above the front for flat ride.