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      04-22-2013, 07:59 PM   #42
HP Autosport

Drives: F80 M3
Join Date: Mar 2007
Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Performance Friction,

iTrader: (34)

Originally Posted by Hogsmith View Post
I am having the RS Pro installed on my 1M later this month at the JRZ HQ in the Netherlands. They suggested 40 N/mm for the front springs and 100 N/mm for the rears and 20N/mm helpers for the dual, street/track use. If I understand correctly that translates into 4kg for the front and 10kg for the rear. That appears way softer than most unless the values for the main springs and helpers should add up, in which case I am exactly at 6 and 12 kilos. I will wait and see how this works out for me.
Helpers don't add to the total spring rate. Assist will add progressiveness, but again, not the overall rate.

4kg front and 10kg rear do seem soft. Be on the lookout for spring bind on the front with such low rates.

For reference you are about 1.5kg higher than OE on both front and the rear.