Ah, interesting. Well, the heat "should" have transferred through the rotor even if that spot was not being used, and metallurgy of the rotor did not change through use, so I don' t think the strength changed any significant amount. I'd be willing to bet the resurfacing did not cut deep enough to completely clean up the faces of the rotors and that's why you still see the ring there. BMW Rotors are spec’d almost to the minimum when you get them new, so most shops will refuse to resurface them or take very little off if they do.
I have a feeling the warpage is a perfect storm of sorts: aggressive pads, aggressive driving, and most importantly machined rotors that were thinner than spec. the combo of all three caused the heat from the track to not dissipate effectively and they warped. (not a professional mechanic but I did spend the night at a holiday in express last night).
In all seriousness though, I bet a new set of Original rotors would solve the problem and also be very effective long term with your pad choice. Just a bit more air when on the track to keep em cool is all you should need after they bed into the new rotors.
Quote:
Originally Posted by Mr. 5
I appreciate the inputs but I know they're warped.
They started to warp before I went to the track, but the track made it way worse.
Here's my thinking...
I had the Rotora caliper kit on the car for a while with the OEM rotors.
The Rotora calipers use pads that are slimmer than the OEM calipers so there is a much bigger ring (closest to the hub) that is not used.
When I went back to OEM calipers, I needed to get the rotors resurfaced (obviously) since the inner part of the rotors was unused.
I believe that because the inner part of the rotor was unused for such a long time, the strength of the inner part was different than the outer part that was being used all the time.
The reason why I'm talking about all of this is because I can still see the inner ring when the rotors are hot.
The heat looks to not be going through the rotor uniformly.
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