Quote:
Originally Posted by feuer
Non m E39 hub is 74.1 vs E90 72.56. Rims aren't interchangeable. That means the rotors aren't either. I'm not sure about e39 M but I assume is the same as non m e39.
You need to look at the hat. Is 50mm for e90 vs 45mm for e39. Don't just look at the center line of the blank.
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Hub face to centre-line is what matters though, because that dictates the caliper position/spoke clearance (along with spoke design and some other things). Unless I'm totally off my rocker and missing something extremely obvious, which is a distinct possibility! In the PDF I attached, I measure from the inside of the flange to the centre-line of the disc, so the hat is compensated for.
As for fitment on the hub; there are two diameters on the hub, one diameter for the rotor and one for the wheel. As such, wheel fitment could vary independently of rotor fitment. I'm not saying that's the case here, you could be correct; but the numbers you cited are for the smaller diameter of the hub, the part that the wheel sits on.
Brembo's European parts lookup seems to be on the fritz and I can't look up the rotor drawings that I've been using (lesson learned: download reference material). I'll have to do some digging and confirm.
EDIT: Centric rotor dimensions from RockAuto:
E90 325i,
E39 540i, and
E39 M5 dimensions. All share the same "hub hole" of 79mm.
Now checking the hubs:
E90 325i.
E39 540i, and
E39 M5. All show a 3.11in (79mm) "brake pilot diameter". Wheel pilot diameter varies from E39 to E90, 74mm and 72.48 respectively.
Cheers.