E30 Rear Coilovers

[williamg]

I'm looking for some recomendations on spring rates for rear coilovers on an E30 325i. The car is being run in RS class, so coilovers are legal. I have searched previous posts and found that 500# to 600# pound springs seem to be a good place to start. How would this transalate to rear coilovers, since the springs are located in different positions. Thanks for your time.

[Bryan Watts]

Should be pretty easy to pull the lower trailing arm off the car and measure to find the motion ratio in order to compare spring rates. I don't know the number for the E30 off the top of my head.

[chuck baader]

I have read the motion ratio on an E30 is .56.....so, a 500# spring would equal a 280# wheel rate. With a coil over, there is some motion ratio that needs to be taken into account....I would assume you would use the center of the tire as the contact patch to figure the ratio. Good Luck, Chuck

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Chuck Baader
#36 ITA E30 BMW
Alabama Region Divisional Registrar

[williamg]

Perfect, thats what I have right now. Thanks