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| 09-04-2015, 10:10 AM | #1 |
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When to replace rear rotors?
Do you guys go all the way to the minimum thickness before replacing the rear rotors? Mine have quite a lip on the outside edge, but still measure 1 mm above the min thickness. No cracking or other indications that the rotor is warped or compromised. Car sees the track several days a year.
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| 09-04-2015, 10:44 AM | #2 |
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Really just depends on your preference, frequency and type of driving etc. - but if it were me, I would do it before the next track day.
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| 09-04-2015, 11:44 AM | #3 |
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I always go to the minimum thickness before replacing (AP BBK) unless I see nasty cracks at the edges before then. I've also gone 1 mm below minimum before too (forgot to check) without any issue whatsoever. At 1 mm above, you are fine.
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| 09-04-2015, 11:44 AM | #4 |
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I'd run them. They are rears.
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| 09-22-2015, 08:53 PM | #7 |
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if there is still some left to go why bother change before track day?
What about fronts? Mine have been forming lips for a while and I have been tracking them. I need to measure them I suppose. |
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| 09-24-2015, 12:00 AM | #8 |
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If you track the car, you should replace the rotors before they are at their minimum thickness.
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| 09-26-2015, 09:22 PM | #9 |
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1mm = 0.039" of rotor thickness left before minimum spec is met. That's a huge amount.
On track weekends, you are likely to lose ~0.001 (one thousandth of an inch) of rotor w/track pads on the rears. Where do I get my numbers? Two decades of measuring rotor wear from track weekends. I don't have as much data on the E9xM3, but from an E30 325iS and E36M3 club race cars on stock brakes, to my E46M3 street/track car I have never used more than 1.5 thousandth of an inch, and that was after a 3 hour enduro in Vegas where the ending air temp was 100 deg F. If I had been at Laguna, then the wear would have been much higher. Measure for yourself and you'll see... Assuming you don't have cracking issues and you aren't running enduros, you've got a ton of life left in my opinion.
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