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      01-15-2015, 08:05 AM   #5
chris82
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Drives: 128i
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2009 BMW 128i  [9.80]
Quote:
Originally Posted by gap View Post
Great research, thank you for sharing this. I was under the impression that the M3 parts firmed the suspension but you are saying it softens it. Not sure I understand this.

"Changing the Guide Rod from OE to M3 removes one rubber bushing and replaces it with a ball joint, resulting in a softening of the suspension.

Installation of a ball-jointed Toe Control Arm (like the Rogue Engineering part) removes two rubber bushings, resulting in a further softening of the suspension."

Good info on the trailing arm crash safety design.
Basically since there is no bushing wind up (which contributes to spring rate) with a ball joint, you are decreasing the spring rate, thus softening the suspension.
Appreciate 6