ipse dixit

As I posted up above, it looks like David has about 2,200 (or 2,300) track miles.

Karl911

Switched to Pagid pads on TTS.
They last longer, cost less than OEs, and do not glaze.
I somed my front PCCB rotor after 30 miles, and 25 track days!

DeerHunter

So, quick back of napkin math:

Fronts are essentially completely worn, while backs are down about a third.
Front replacement cost = $10K/2,200 track miles = $4.55/mile
Rear replacement cost = $10K/6,600 track miles = $1.52/mile
TOTAL = $6.07/track mile (not counting cost of pads)

Yes, there are less expensive refurbishment options available than buying OEM PCCB rotors but, all else being equal, that is still a pretty hefty price tag. Who's done the same calculation using iron brakes?

RDCR

Translation please?

SanDiegoDavid

Sorry guys about the confusion, total track miles: 2350 (26 days). The 511 track miles (6 days) was the difference between the December 2015 and March 2016 measurements.
I know the carbon density measurements are the most important with regard to the PCCBs, but what specifically does them getting to the wear limit mean? Visually they look the same. So at this point are they at higher risk for physically degrading (crumbling/flaking)?

SanDiegoDavid

, at least initially I want to keep both! I'm doing COTA at the end of April, so need to figure this out. Looks like I will just get new front rotors, but which ones? OEM or Movit? I think I will keep the OEM calipers.

SanDiegoDavid

I'm little surprised by the sudden drop in the density measurements. Based on the previous information and the good work of others to calculate the degradation curves I was not expecting to faced with this issue for another 10-20 track days.
Obviously the degradation is not linear.

DeerHunter

My understanding is that there are three possible ways of toasting a PCCB rotor:

1. Chip the rotor itself (either user error or possibly an errant stone)
2. Wear the coating off the surface (this type of degradation is easy to spot).
3. Degrade the carbon content of the rotor (not visually apparent but can be determined using the densitometer or by weighing the rotors)

You're experiencing the latter and therefore you just have to trust the measurements. Once beyond the wear limit, I'm not sure what the failure mode is, but I suspect the rotor will be at risk of crumbling.

Again, going by previous posts by people more knowledgeable than me: Extreme heat (as you'd generate when tracking hard) oxidizes the carbon from the carbon/ceramic matrix. It makes sense to me that as the amount of carbon reduces over time, you have less of a "heat sink" and thus you experience higher-than-normal temps and accelarate wear in a non-linear manner.

ipse dixit

Perhaps get a second opinion? Maybe see if Hoehn up the coast will measure them for you?

PierreTT

Great Intel David, thanks again for sharing

I would try to get a few more days out of it (if you did not noticed any change in the way they feel...)

I started this tread last year but just sold my GT3... RS coming in July.

Even if I'm not tracking the car a lot (7-8 days per year), I'm leaning toward the red calipers this time ... Just dont want to think about my brakes all the time while I enjoy the car on the track!

Still have a few weeks to change my mind (or not)!

Jason @ Paragon Products

That's the feedback we're getting as well...nice when it works that way. We've learned to keep them on the shelf.

http://www.paragon-products.com/Pagi...4927-pagid.htm
http://www.paragon-products.com/Pagi...id%20u4925.htm

meaker

So these pads will work on pccb? Do they keep the pccb rotor from where as quick? I guess I mean do they build less heat or more in the rotors since that's the killer.

Jason @ Paragon Products

Yes sir, the RSC compounds are made specifically for use on ceramic rotors. The RSC 1 compound is rotor friendly and very good with regard to heat conductivity. You can view a diagram of characteristics here:

https://www.paragon-products.com/kb_results.asp?ID=97

Karl911

yes, i would conclude that glazed pads are not good for the rotors

porscheflat6

See you at COTA! I will be there at the same time for speed Ventures