Quote:
Originally Posted by badfish
Ok now for educational purposes, help me understand this. I'm looking at the calipers now. I've seen guys make brackets to fit virtually any caliper to any car. Somehow this won't fit other cars? How come they can't make these calipers fit another car if they can make a bracket for the Stoptech ST60 and ST40 calipers on my car? I'm just curious, not being argumentative. I'm in no rush to sell these, just putting them on the market for someone to retrofit. I wasn't aware of rotors costing more than calipers...
|
There are three things that all have to work together to make these brakes fit and perform. The caliper bracket, the caliper and the rotor. The dimensions that matter are the relative locations of the caliper bracket bolts to each other and to the centerline and facing plane of the wheel bearing, all of which are determined by the knuckle design.
Usually within a BMW car series, they keep these spatial relationship dimensions constant and change the three components so that brakes from a model with large brakes are interchangeable with its smaller brethren, provided you use matching rotors, calipers and brackets.
What's different with the E9x M3 is that the M3 front wheel bearing is borrowed from the E6x M5/M6 and it's mounted on a specially designed knuckle. While it's possible that the critical dimensions for interchangeability were maintained, BMW themselves probably didn't consider it a priority. Their focus was on making the M3 work, not on making sure that M3 parts would fit a series of cars they weren't made for.
So, specifically - could an adapter be made? - maybe. If a skilled machinist was working on their own car, it'd be do-able. For an enthusiast looking for an upgrade it would be cheaper to just buy a BBK.