Quote:
Originally Posted by NonoxX
Hello,
I've just been told by an experienced mechanics, moreover race driver especially on BMW, that the usual 1M Front Control Arms mod on (in that case) a 135i is not a good one: according to him, it makes the car unsafe and unpleasant to drive.
The reason he gives, is that the wheel carriers are different ( 31216793923 vs 31212283435), therefore the suspension overall behaves differently (thus the different arm lengths). He told me, that when steering, the inner wheel would turn waaaaay too much compared to the outer wheel. This could be OK for drifting, but not race driving.
What do you guys think? Did you already hear that? Is this simply an alignment issue?
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I think this applies to the REAR knuckles more so then the front. The pickup point fro the rear toe arm is significantly different on the M3 which is why you can't use M3 REAR toe arms.
However, the pickup points on the front knuckles are damn near the same. The Knuckles are different but I think it has more to do with the orientation of the strut (Caster) than anything to do with the control arm pickup points.
The longer M3 control arm does affect the wheels dynamic range of motion though without a doubt. It probably adds bump steer. I would just argue against it being "unfavorable" or "drift-car" since anyone doing M3 control arms also probably has lower offset wheels and/or spacers which would negate this. The 1M uses the same front knuckles as the 135i but also uses the M3 control arms...
If you were still running stock high offset 7.5" wheels with 225 wide tires i'd say maybe it might feels weird (it does when I use my winter wheels), but, with low offset 9" 255/40 up front the car feels better.
the other big issue is that you are widening the FRONT track width but not the rear. So, yes, again, could have negative consequences (more playful rear) but not if you understand track width and you also widen the rear to match... or play with spring rates to account for the difference... etc.