Quote:
Originally Posted by M3SQRD
Are you sure the rotors didn’t have a small amount of oil applied to the surface to eliminate any corrosion? It used to be applied to all AP Racing rotors (in 2003I had the e46 M3 CP5555/CP5144 calipers, 355 mm F rotor and stock R rotor) as well as other major known brake manufacturers. You had to literally give your rotors a bath in soapy water! I’d always hit them with brake clean as well.
However, the AP Racing rotors supplied with the Essex/AP Racing CP9668/CP9449 brake kit did NOT come coated in oil.
034 had a few rotor failures and/or large cracks on Audi applications at the curved midpoint between floating attachment hardware on the rotor.
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Yes, because a very thin coating is applied to the rotor to prevent corrosion while sitting on the shelf waiting to be sold. This is what gives the rotor a matte silver finish, and this coating is extremely thin, literally if you rotate the wheel the pad scraping by will beging to scratch this coating and upon the first brake application the entire coating will be wiped off the rotor. This will expose a normal metallic sheen underneath.
Here's the instruction saying not to use soap or cleaners on it either (although if you touched the rotor while mounting and had greasy or dirty hands, then it would probably be wise to spray it with brake cleaner):
This is a new style of coating that also gives lasting corrosion protection to parts of the rotor that don't undergo braking - i.e. the hat mounting points and the vanes:
If you look at my rotors you'll notice the friction ring is worn and is now looking like a normal rotor. But the center near the hat is still silver because the coating is undamaged, and that part will be protected from corrosion. The outer most edge is also still coated because the pad is not sweeping there, and that outer circumference of the rotor is still coated too meaning the vanes are also protected from corrosion.
I haven't seen any rotor failures from 034 iirc (rotor failure being they literally broke in half or broke off the hat), but I have heard about the premature cracking on said Audi's after a few track days (3ish track days I can't remember). That being said, on BMW specific applications I have never heard of any issues. Blake's garage uses these rotors on his extremely high powered M4 with decent aero and very grippy tires (I can't remember if they were R compounds or slicks) has reported that they are still going strong despite many many track days, Jfritz above (
https://f80.bimmerpost.com/forums/sh...94&postcount=3) has 12 track days and has normal wear on his rotors with nothing looking concerning. They show the same traits (minor crack formation evenly distributed amongst the surface of the rotor) that any rotor would have after that much track use. So I am lead to believe that the audi related wearing might be limited to audis and could be due to an audi related brake style torque vectoring that some AWD cars use - but I don't know much about audi's at all. I do know if we leave mdm mode on our cars use the rear brakes as part of the dsc system and that is greatly responsible for our premature brake fade on track.