Example rebound force and r-zeta curve. The rebound force at each velocity is used to calculate r-zeta. The ultimate goal is to adjust the rebound force for the application/ride type and spring rate. Valving changes are made to alter the curve.  For example, increase high speed rebound. The three areas of the curve that can be controlled independently of the others are: 3ips 10-20ips 70ips Ignore 1-2ips. This technique also allows you to check any rebound setting to determine if it's in the ballpark.