OK: I'm slow to make changes, but after playing with adding some more rake to the setup of my RF89 Special ("Special" for the rebuilt front end that resembles the later Van Diemens with two-shock front ends), I've realize just how much understeer I was dealing with mid-corner.
With the rear ride height increased by more than 50%, and using full stiff rear and full soft front roll bar settings, the car was still not close to oversteering.
And since I finally tore the suspension down to its constituent parts, I'm starting to understand why: My rear springs are 500 lb/in, but with the 0.5 motion ratio of the RF89's rocker-arm system, that makes the wheel rate only 125 lb/in. Does that seem like enough to anyone? If the rule of thumb is to run something close to corner weight as your wheel rate, then that seems really low to me.
Does anyone have any info on the spring rates they run on an RF89? Or how about wheel rates (or spring rates and motion ratios) for something like an RF90-93?
My rates currently are are about 225 lb/in front (springs are 225 and the motion ratio is close to 1:1, although I've not yet measured) and about 125 lb/in rear (500 lb springs with a 0.5 motion ratio).
With the rear ride height increased by more than 50%, and using full stiff rear and full soft front roll bar settings, the car was still not close to oversteering.
And since I finally tore the suspension down to its constituent parts, I'm starting to understand why: My rear springs are 500 lb/in, but with the 0.5 motion ratio of the RF89's rocker-arm system, that makes the wheel rate only 125 lb/in. Does that seem like enough to anyone? If the rule of thumb is to run something close to corner weight as your wheel rate, then that seems really low to me.
Does anyone have any info on the spring rates they run on an RF89? Or how about wheel rates (or spring rates and motion ratios) for something like an RF90-93?
My rates currently are are about 225 lb/in front (springs are 225 and the motion ratio is close to 1:1, although I've not yet measured) and about 125 lb/in rear (500 lb springs with a 0.5 motion ratio).
No wonder the car understeers: RF89 spring rates
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