Understanding spring rates

DIY or TECHNICAL
13

A quick guide for calculating the required spring rates (the method i used). It focuses on springing the car to a certain frequency.

          (4p² x fr² x m)/1000

The result will be the base spring rate in N/mm

‘p’ = pi (for some reason the pi symbol doesnt show)

‘fr’ = the frequency in Hz

daily= 1Hz
Sporty street = 1.5Hz
Track day (Semi slicks) = 2Hz
Race (Quality semi’s or full slicks) 2.5Hz
Over 2.5Hz sprung frequency is for cars with alot of aero downforce.

‘m’ = the corner weight (minus unsprung weight)

These figures can be used for a rough estimate

For FWD

              m (front)  = (vehicle weight x 0.315)

              m (rear)= (vehicle weight x 0.175)

For AWD

                m (front)= (vehicle weight x 0.295)

                m (rear)= (vehicle weight x 0.195)

For RWD

               m (front)= (vehicle weight x 0.275)

               m (rear)= (vehicle weight x 0.215)
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