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      11-16-2012, 09:35 AM   #25
Porschefile's Avatar

Drives: E92 M3
Join Date: Jul 2008
Location: Tennessee

iTrader: (7)

Originally Posted by Richard@M-World View Post
The issue is not where the helper is (it actually comes at the top from KW), the issue is the total length of the spring + helper which could interfere with the wheel/tire.

Don't forget leverage. The spring in the rear is seated inboard, so the effective spring rate at the wheel is much less than the indicated spring rate.

The conventional knowledge is to soften the front if you have understeer. Unfortunately as you can see from the flow chart, the actual process is a lot more complex.

Also, when you increase the rate in the front, you will need to match the rear spring with it. Try the 520F/800R rate first with a squared set up. You should like the balance much more.
Exactly, but that just makes it ever more likely that the front is too stiff. The rear effective rate is in the 200's IIRC; the front is in the 400's. I pulled the wheels last night to install studs, and the helpers are not fully compressed at my current ride height so I left it alone. I test fit the 275/18x10 combo and it rubbed without and spacer and did not rub with a 5mm spacer. I took a couple of pics of the strut if anyone still wants to see.