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      05-25-2020, 03:56 AM   #14
roastbeef
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Quote:
Originally Posted by raceyBMW View Post
That's what I was suspecting as well after seeing the rotors. Any way to come back from this without new pads? Will sanding/honing rotors and scuffing the pads be enough?

I was hoping sticking with PFC street and race would be compatible enough, but evidently not.
i'll expand a little bit. i could have had a combination of problems that i didn't realize at the time. i had a track day at willow springs, no really big braking zones, just a few places you tap to get down to the appropriate speed. there is only one place where you threshold brake for about 1.5 seconds. i took a set of race pads down to about a 1-2 millimeters (cobalt friction xr1 - they didn't chunk apart!), but i could feel through the pedal they weren't right. swapped pads to my backup ferodo ds2500's, good to go for the rest of the day.

fast forward to my next track day at laguna seca (three hard brake zones, no long straights to cool brakes), i had a set of endless me20's that i wanted to try. i didn't realize this at the time, but those pads like to be bedded in a certain way, and i already had a nice layer of another compound on the rotors. i was experiencing what i perceived to be brake fade, problem is, these brakes don't fade. i had a soft pedal that would get better with one pump. it wasn't knock back, it happened at every corner and i have anti-knockback springs. i had to lengthen my braking zone, and when i did get that second press, i had ok torque, but not much bite.
so i came up with two theories-
(1) i cooked the srf my previous track day at big willow and just didn't realize it when i took the pads down way too low and they held up (putting a lot of heat into the caliper).
(2) the me20 pads are a different compound and i learned they like a specific bed-in procedure.

i haven't used the me20 pads again to test this theory, mainly because i'm tired of experimenting with endless (no pun intended) amounts of available race pads and i'm just going to proceed with the cobalt xr1's that i love, but the original post reminded me of this experience.
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