In Reply to: Re: Race Pads for Driving Schools - longish posted by KJK on March 30, 2000 at 16:39:36:
"My question is on the rotors. How long do they last? When are they worn out? They are $90 each for an M5 unless I can find some good ones cheaper so it is not insignificant. Any reason to have a separate set of pads and rotors for the track?"
Indeed, OEM E34 M5 brake rotors are about twice the cost of those on my 535i, that I descibed as cheap. Rotor wear would be more of concern for me if I was driving an E34 M5. For that matter, incarceration would be a concern if I was driving an E34 M5. I'd guess that OEM with a BMWCCA discount is about a inexpensive as you could go for rotors. I think it's a good idea to have the shop measure thickness at your Inspection II. I don't know what the minimum spec is for M5 rotors. You need the spec and a good dial caliper or micrometer to measure thickness.
Separate pad and rotors for track? I'm not sure.
No doubt most pads bed-in to conform to the rotor. However, I think the race pad is so aggressive it will bring the rotor back into compliance even after thousands of street pad miles. I could be way off on this.
Other thing is this mysterious 'film' generation that some race pads are supposed to produce. Notably, the PF90's and others, coat the rotor with a film of pad material so high friction coefficient and lower wear results. I hear you can see the brownish film on rotors using PF90's. Figures you might want dedicated rotors if this causes transition problems. Tuner Motorsport told me the Hawk Blues don't film. The product literature says they do. Using them, I've seen no evidence of filming. Still all VooDoo to me. Guess I'd talk to Turner. Sorry, I'm not much help.