Spring rate for rear coilovers

[evilC]

I've found some data that is food for thought;

Car: Rear engine, rear wheel drive.
Weight: 970kg dry 40/60 split front/rear; 1145kg wet including fuel and driver, split 43.6/56.4 front/rear
Wheel rate front; 6.5kg/mm (368lb/in) = 368lb/in spring rate for a 500kg front axle load max
Wheel rate rear; 8.5kg/mm (482lb/in) = 616lb/in spring rate for a 645kg rear axle load max
Damper rate front; 180/80kg
Damper rate rear; 300/90kg
Frequency front; 147
Frequency rear; 137
Note that the weight will vary due to the aerodynamic loads. In this case the front lift was -0.05 this gave a down force of 20kgs @ 125mph and 45kgs @ 187mph with rear lift of -0.26 giving a downforce of 105kgs @ 125mph and 235kgs @ 187mph.


The car? This was the all conquering Porsche 935/77. The circuits it ran on were invariably billiard table smooth so the suspension ought to be considered at at the very stiffest end of the spec. I was interested to see how close to the same weights some of our bugs were.

Clive