M3 Control Arm Bushings...

[Brew]

I searched...

What exactly do they do for the geometry of the suspension?

And how do they affect handling and stability?

Thanks in advance.

[Charlie]

They offset the control arm, giving you a little more caster. Helps high speed stability and makes turn in feel a little better on higher speed corners, imo.

-Charlie

[Brew]

Cool.
I've noticed that with the wider, 225 es100s my car feels a little "squirrelly" at higher speeds. I know that the control arms and bushings were replaced about 15k miles ago by the PO, so I think they should still be good. There may be some other bushings out front that are worn out, though.

How do the offset bushings affect tire clearance?

[nando]

they move the wheel forward a small amount. unless you are already close to rubbing the front of your fender liner, they don't really affect tire clearance any noticeable amount.

[Brew]

Alright, I think I'll be OK clearance-wise, as the 225/50-15 are actually a tad bit undersized in overall diameter.

[rwh11385]

they move the wheel forward a small amount. unless you are already close to rubbing the front of your fender liner, they don't really affect tire clearance any noticeable amount.

This is true. Only time it'd really matter if it you were me--cheap and deseperate--and ran 205/60-15 would the wheel coming forward come into play to make a problem.