Suspension tuning “rules of thumb” specify the damping targets needed for a baseline suspension setup. Collectively, those rules also define what a “good” damping force curve “looks-like” with specific low, mid and high speed damping targets.
Those damping targets allow shock valving calculators to fine tune the progressive or digressive damping force curve shape needed to match damping requirements for the specific vehicle weight and spring rate.
Baseline damping targets:
- Rebound damping: zeta= 0.707 across the stroke depth range
Rebound damping
Riders have an uncanny ability to twirl clickers and hit rebound damping at zeta values of 0.7. The reason is simple. Rebound damping stiffer than zeta 0.7 gives slow response causing rebound to pack. Softer damping below zeta 0.7 allows the suspension to baby-buggy after a bump giving poor suspension “feel”.
Lower values of zeta 0.5 overshoot race-sag by two inches producing a large baby-buggy motions and poor suspension “feel”. Zeta values of 0.7 get back to race sag fast, minimize overshoot and provide damping stiff enough to suppress resonance motions.