We have been doing lots of research looking for off the shelf rotors that will work with the 135 6 piston calipers on the E30 M3. The biggest issue with the M3 is there is VERY little clearance between the rotor and the tie rod. When you go with a really big rotor. The stock M3 rotor is very shallow, right around 40mm.
So after digging through lots and lots of different rotor specs for all different cars we think we have found something that will work. This rotor is 330mm by 28mm and NOT off a BMW. Once we know everything will work we will say what it is off of. We don’t want misinformation out there. It is only 39mm deep so there is around 7mm of clearance at the tie rod.
Now this rotor will need some machining but it is close. The center bore will have to be opened up a little bit and the wheel studs will need to be ob-longed inward.
Ultra flat rotor.
Bolt holes are close…
Ground down the rub of the m3 bearing (will be replaced anyway) to be able to set the rotor flat against the hub.
Tie rod clearance
Need to make a bracket…
Mocking up in a 17″ wheel
Now this wheel will not clear the caliper. If you look there is some wood stacked to get it to clear. So we will need a different wheel setup. There is around 22mm of “spacer” right now.