Uneven wear with AP Racing Sprint BBK

[puma]

well it is too late, everything is now gone in the car

[86Nanny]

Originally Posted by puma

well it is too late, everything is now gone in the car

haha. Well if you end up with car #2 and need an easier/cheaper route. Let me know and I'll be glad to help.

[philooo]

I wanted to see if you solved your problem ?

I went to Homestead last weekend with brand new CL6E and new essex sprint kit, I tried my best to bed the pads, and had a good bluish coat after my first run but after the second session, I don't have the bluish color evenly on the rotors.

I have not yet removed the pads, I'll try to do that this week.

what's the update in your case ?

I had slight vibration in the steering on braking if I hammered the brake too much, after driving back at 75% for a few laps, the vibration went away.

the driver and passenger side rotor look similar to the photo below.

[rice_classic]

To the OP and possibly Philoo too:

Sometimes the answer actually might be: That's just the way it happened that time.

I shit you not.

That longitudinal taper is normal, however it is rather pronounced in your case but I think what caused the excess wear was also what exacerbated the taper.. That would be transfer layer. This happened on a CarboTech pad which have a poor reputation in regards to transfer layer (bedding). All it takes is a pad that can't quite bed-in to wear really fast, really weird or cause awful vibration under braking (uneven layer). Sure, there could be a problem with the car setup or the braking nannies or whatever but do not disregard the possibility that it may be simple, it may be a pad that didn't bed. I think the official bedding instructions of Carbotechs actually involve prayer...and maybe a sacrifice, well usually something ends up getting sacrificed.

I've been racing an under-braked car for over a decade now. I've tried just about every pad that's made for my backing plate and I've seen every problem a shitty transfer layer can cause and the OP (and Philoos) issues are ones I've experienced more than once and for me both were caused by the pad layer.

Another thing.. some pads will put down a buttery smooth transfer layer easily, each and every time, but only with new rotors. Other pads don't care if the rotor is used or not. I have 2 compounds I swap between and 1 prefers new rotors while the other doesn't care.

Finally: flip the pads on the rotor after a couple sessions, this will allow the pads to un-taper themselves longitudinally. Tapering is also a self perpetuating problem, once a pad starts to taper the rate at which it tapers accelerates during it's life. Flip those pads.

With a mono-block caliper you should experience little to no lateral taper (inside to outside of pad) like you would on a floating caliper.

[philooo]

thanks @ride_classic to make me feel a bit better, hopefully it is only the pads.

My next question will be : should I dump this set of pads and hope may be next set will clean up the rotor uneven wear ? or my rotor will keep these mark forever most likely ?

In my case the car was just aligned by a reputable race shop and I do the pedal dance each time before I went on the track.

what pads are known to be easy to bed in I think I need one of these because it seems the OP also had problem with the CL6 pads.

[rice_classic]

Originally Posted by philooo

thanks @ride_classic to make me feel a bit better, hopefully it is only the pads.

My next question will be : should I dump this set of pads and hope may be next set will clean up the rotor uneven wear ? or my rotor will keep these mark forever most likely ?

In my case the car was just aligned by a reputable race shop and I do the pedal dance each time before I went on the track.

what pads are known to be easy to bed in I think I need one of these because it seems the OP also had problem with the CL6 pads.

I use only "race-only" compounds but in that vein I like the Raybestos ST42 and ST45 and the Cobalt XR1.

Ping @CSG_Mike and ask him as well, they carry and have experience with compounds that I'm unable to try (not made for my application) and may be ideal.

[Sleepless]

Any updates on this?

[DarkSunrise]

I've been having a similar issue lately. LF pads wearing much more quickly than RF, particularly the inner pad which has a tapered wear pattern. Last 4 track days were at Summit Main and VIR which are CW, so that might be my issue.

I'm on a mild setup - stock brakes with XP10 pads. My last set of pads lasted 6 track days, so I'm not nearly as hard on the brakes as others. I'm going to either rebuild the caliper or put in a remanufactured caliper, and switch to XP12 pads and fresh rotors. Fingers crossed...

[ubernostrum]

Originally Posted by DarkSunrise

I've been having a similar issue lately. LF pads wearing much more quickly than RF, particularly the inner pad which has a tapered wear pattern. Last 4 track days were at Summit Main and VIR which are CW, so that might be my issue.

Are you doing the pedal dance? I had an issue with the EBFD causing uneven wear on the fronts with the AP Sprint kit. That was when I was just doing the 5 second push to turn off TC. Once I started doing the pedal dance the wear became normal and even.

[DarkSunrise]

Originally Posted by ubernostrum

Are you doing the pedal dance? I had an issue with the EBFD causing uneven wear on the fronts with the AP Sprint kit. That was when I was just doing the 5 second push to turn off TC. Once I started doing the pedal dance the wear became normal and even.

Just the 5 second press. I'll try the pedal dance next - thanks for the tip!

[LOLS2K]

Originally Posted by DarkSunrise

Just the 5 second press. I'll try the pedal dance next - thanks for the tip!

Which track are you running at? I did a lap at Street of Willow with 5 second press, and the nannies kept interfering. So annoying, and definitely held me back. Pedal dance solved all of that.

[Anthony]

A+ read. Hoping for an eventual movie adaptation.

[DarkSunrise]

Originally Posted by LOLS2K

Which track are you running at? I did a lap at Street of Willow with 5 second press, and the nannies kept interfering. So annoying, and definitely held me back. Pedal dance solved all of that.

My last 2 track weekends were at VIR and Summit Main. I can only think of a handful of times when I felt something kick in slightly mid-corner, but it's never spun me out so I never bothered doing the full pedal dance. If it will fix my brake wear issue though, I'm all for it.

[ZionsWrath]

Just used a new set XP10 this past weekend. They are tapering top to bottom, rears wear normal. I guess its same thing, need do pedal dance?