Chris's new build of an MX5 based car

[CTWV50]

Originally Posted by skov

I think I've got 325lbs on the front at the moment, and only have a tiny bit of preload.
With 250 springs I needed lots and lots of preload!




It can, but not directly. You have to take account of the damper angle in the leverage ratio. Can't remember how to do that off the top of my head though!

Hmmm, I don't know. It feels ok but only had very limited testing really. Also I'm using the centre of the wheel for the A-B dimension, and using ET15 not standard mx5 ET38 wheels and I've moved the shock wishbone mount out around 20mm, so there really is a lot more leverage on the spring. Also I've only got 1" of shock travel for droop due to the 13" shocks but it gives me 1.5-2" droop at the wheel. I guess like you I'll have to see how it behaves on the road and take it from there.

If I suffer understeer due to the front spring rate, I had the mad idea today of making a rear ARB. But I'm going to forget about that for now, sounds like trouble! I can always try a lower spring rate and try preloading them.