Front Brake Rotor Question

[Blue Streak 21]

I have a question for the group. I replaced front rotors before my first auto-X. I used the existing brake pads (PFC), as they looked to to be in good shape (decent remaining pad material).
I ran 15 laps with the car and now my rotors look like this. I was quite surprised how abrasive the pads are. They dusted like no pads I have ever used. The pads also wore away a bunch of the rotor.


The outer ring (about 1/2" wide) is untouched by the pad. The inner ring (1.5" wide) is where the pad wore away the rotor. The inner ring is 0.010" (outside) to 0.014" (inner) lower than the untouched part of the rotor.
The old pads have the exact (mirror image) profile as the rotor. Evidently they wore unevenly on the previous rotor.
I plan on replacing the pads. My question is whether I need to get the rotor surfaced before I put in the new pads? These PFC pads are very abrasive, will they even up the rotor, or just conform to the surface?
Is this kind of wear normal for these agressive PFC brake pads? The wear seems high, but is that because the pad didn't bear against the entire width of the rotor?

[Gatorac]

You may find that the pads are not well suited to autocross. These pads need to be hot to work properly. You should notice less rotor wear when the pads are used at the correct operating temperature.

New rotors and pads also need to be properly bedded in. They must be brought slowly up to operating temperature and then allowed to cool completely. This is true even if your just replacing the rotor or pad. The typical autocross is insufficient to get the proper heat into the rotor or pad.

If you don't resurface the rotors, the new pads will wear uneven.

[Blue Streak 21]

Jim;
Good advice. I did bed the rotors before the auto-X, allowing them to completely cool before track use. Still don't understand the high wear on the rotors. The auto-X format was continous lapping for 7 minutes to practice the course. Not the usual one lap, then stop and wait 30 minutes for another lap. So I think the brakes should have warmed up nicely. The pads that caused the problem we're down to about 1/3rd of the original thickness. Could they have gotten harder and more abrasive with increased number of heat cycles?
I resurfaced the rotors this afternoon and installed the new pads from Gary Jones. Thanks Gary! I will bed them before the next track day on Sunday. I'll see if these new pads work better than those ol' worn out POS. Hope so, because if not, my day will be very short and expensive.

[panoz302]

maybe the old pads did not transfer any material to the rotor as the rotors where so new and the pad temp was not high enough, then when you really got into the brakes the old pads just tore into the rotor. I have seen this with high temp pads not being given enought time to pad material on the rotors and heat up the pads. Did you change compounds, I want to change to PFC 01 from the 97s as I feel the 01 have more bite and are closer to my driving style. I feel the 97 which are good when hot do not have enough torque for my liking, too much pedal pressure required.

[Cobra4B]

Which pads come in the school cars? Mine are basically brand new so I'm going to run through them first.

[Blue Streak 21]

Brian;
The stock pads are PFC 97's. I got the P/N somewhere, and I think it's been posted on this site. Check out gatorac's web site for spec's. I'm pretty sure it's there too.

[Cobra4B]

97 Compound has less initial bite and average torque than 01 compound. 97 compound has excellent modulation, a very flat torque curve, and enhanced release characteristics. 97 is considered PFC "Endurance Compound" with the lowest wear of any PFC compound and is also highly recommended as a general purpose pad for club racing and track day events.

Sounds like the perfect long lasting HPDE pad... I'll see how I like them at VIR next weekend.

[Blue Streak 21]

Brian;
I'm interested to hear how the pads, and car does at VIR. That's one of my top 10 tracks to drive... One day....
I'll let you know how the pads do at my track day. New pads, freshly machined rotors. Best of all worlds. I have high expectations for the pads doing well. I'm just hoping the car handles well, and that the rain stays away.