Socalconstruction1

XP 12 and XP10

Socalconstruction1

yeah I was wondering about balancing. Yeah bead locks means two new sets of rims for me. I've never even seen anyone with them other than Drag and Off road/sand

Scooter70

The inside of the bead on the wheel can be knurled. That would help to hold the tire to the wheel. The thing about balancing wheels/tires on the roadcourse is that you're always picking up OPR (other people's rubber) so in a sense, balancing does nothing after the first lap. I actually haven't bothered having my scrubs balanced in years because there's already some rubber buildup on them when I get them and there's only going to be more of it after the first few laps which will throw off the balance anyway.

0Todd TCE

This is a common problem on race cars with powder coated wheels. And shows up with lug nut issues also. Try to avoid PC in the bead...

brkntrxn

Generally, the front tires will slip on the wheel under braking and the rears slip under acceleration. I have also noticed that the most slippage will occur in the first session before the tires are fully warmed up. any time I warmed my tires by aggressive weaving on the outlap before doing brake/gas warming, the tires slipped less. At least that has been my experience.

TKOGTO

Glad to hear this. Early/excessive ABS intervention is a real drag. I have had it myself on 2 different occasions for 2 different reasons. My experiences are similar to yours in many ways so bear with my 2 cents. I have a) the Wilwood calipers, W6As up front, FNSLs in back b) used both MPSS' and R888s c) spoke with Carl several times d) use both the H and B pads e) use the BP-20s on street...

In the 1st instance, the pads were not properly bed and the rotors may have had 2 different compounds of them. Correcting both cleared up the early ABS. The 2nd instance was user error. My initial brake application, engrained in my foot from spending much too long on street tires and HP+ pads, was just too hard for Bs or Hs even on r-compounds. A softer application kept me out of Ice Mode and excessive ABS at bay. Newer tires helped but did not eliminate it.

I see from your prior posts that neither apply to you. Absent the wrong piston sizes, the cause still seems a mystery. What I can reiterate is the calipers are not only good for Hoosiers or slicks. They have worked just fine for me on street and r-compounds. I have found the XP-12s to have a moderate amount less initial bite and a fair amount less overall torque than the Hs but that's just me. This goes back to the brake application. Either way, stick with what works and glad it's fixed.

Scooter70

I wanted to revisit this thread after my first weekend with my Wilwood 14" Race kit on my car. The above is 100% what I experienced. Even on Pirelli slicks, I needed to soften my brake pedal push even more to keep the wheels from locking up. I'm pretty easy on brakes and don't stab on the brake pedal but these brakes with the H-pads definitely grab and need a soft application on the pedal, especially when pads/tires are not yet up to full operating temperature.

SocalC5Z

I'll add my data...first I'm glad the OP has resolved his brake issues. The knowledge base on CF especially Brkntrxn and Todd from TCE is extensive.

I purchased the Willwood Aero 6 BBk from TCE two years ago and run the H pads on the front and ST-43's on the back (simply because I had a small stockpile of the ST's) and couldn't be happier with the vastly improved performance on the track and reduced cost of consumables. This is the WW 14.25" BBk on my C5Z

NemesisC5

Are you running oem rear calipers or WW Aero 4's?

SocalC5Z

I'm running OEM calipers in back with zero braking issues. In a nearly stock C5Z with nothing more than T1 bars and a track alignment, there is enough weight transfer under braking to reduce the rear brakes effectiveness to the point that I don't think I'd see any improvement in overall braking with more rotor or squeeze. The car with the 14.25 BBK in front will brake about as well as anything else with two doors and a license plate.

Sure, it would be nice looking to have matching rear brakes and the consumables cost would go down, just like they have in the front, but for now, i can put the money to better use in other areas.