I have done a bit more research on this, had a good chat with Dave Cooper at Track Developments. He will be able to work out the exact rate and length for us all. What's needed is the respective weights and desired ride heights of the cars - mine's a bit bare at the moment! The un-sprung weights will be easy for me, and I guess the fronts are all going to be the same. So if anyone can chip in with their car weight, front to rear will be ideal, I can start to collate it all and get Dave started on some calculations.
Q. does anyone else have 300lb front springs ?
BTW he can also sort out most other handling faults and settings on finished cars. The web addess is
www.trackdevelpoments.co.uk
Cheers,
Martin