Determining Carbon Ceramic Brake Disc Wear

[911boost]

And by steel I mean iron….

[Gus Berges]

If it's just pads and rotors, then it's just like a regular originally equipped steel rotor based truck?! I have yet to confirm if this is in fact how it'd be. Sent out a couple of messages to a few shops to see what they come back with.

The original rotor size on this truck is 410mm (fronts) and 370mm (rear), but the steel Turbo brakes are different sizes (390/358), thus leading me to believe that it's not just a simple swap of rotors and pads, but I could be wrong.

Will ask the local dealer to put it in writing to be safe just in case. Still no news from Monday's PPI. I wonder why....

[911boost]

Giro Disk makes a 410mm iron rotor.... I would call them and ask if anyone has bought them for a Cayenne.

It is all speed sensors, those will not be affected by changing the rotor material.

[Gus Berges]

GiroDisc is closed on Fridays. Still waiting for some other shops confirm if in fact they have a solution for my need.

Some more "cool trivia information": I just got done talking to a very large and reputable Porsche dealership in USA and the person told me that you can in fact "easily" swap out PCCB disc for Porsche steel (Turbo) discs,*BUT THIS CAN ONLY BE DONE IF YOU HAVE 390MM PCCBs.

The truck I'm looking at has options 1LX (Front brake discs for min. 20" wheels, yellow calipers (PCCB)) and 2EH (Rear brake discs for min. 19" wheels, yellow calipers (PCCB)) which means that the front discs are 410mm, not 390mm. PCCB 390mm front discs use the same caliper as the 390mm steel discs. Cayennes equipped with options 1LX and 2EH have different calipers from all other models. If you want to change to steel discs, then you need to basically change calipers, rotors, pads, knuckles and a whole other series of parts.*

I'm not 100% sure, but I believe that these are the following correct sizes (front/rear in mm): PCCB: 410/370 ; PCCB 390/358; Steel (Turbo): 390/358.

@911boost: did share this on Rennlist too...

[911boost]

Huh, that is interesting. Maybe because Porsche does not make a 410mm iron rotor they say you have to do all of that? If you can in fact bolt the 410mm irons to the stock Porsche hats I cannot see the caliper not working, but the Porsche dealership would know way more than me.

I bet picking up the calipers used would not be a problem at all, the knuckles and what not would be a pain in the ass. I am in the process of swapping from 6cyl to V8 spindles and disc brakes on my '66 Mustang and even that is pain and requires a lot of random parts.

No matter what this is all very interesting.

[herr_oberst]

Originally Posted by 911boost

No matter what this is all very interesting.

Agreed.

[Gus Berges]

More data.... Most of the 410/390 conversions from PCCB to iron/steel rotors are designed to be used on the GT series (997/991/992). Nobody has ever heard of a 410mm iron rotor for a Cayenne (it's all about getting the brake hub/hat correct).

Apparently Brembo makes a 405mmx34mm iron rotor that fits a Cayenne Turbo. They also have a 412mmx38mm iron rotor that supposedly fits a Cayenne Turbo. Waiting to hear back from Brembo to see if either of these two solutions would work to replace the original 410mmx36mm ceramic discs on a Cayenne. Then it's onto finding replacements for the rears which are also "oddly/uniquely" sized...

The head tech at the Porsche dealership (USA) said it would "more than a pain in the a$$" to switch spindles/mounts/calipers/etc. so your comment above makes perfect sense.

[masraum]

Originally Posted by Gus Berges

GiroDisc is closed on Fridays. Still waiting for some other shops confirm if in fact they have a solution for my need.

Some more "cool trivia information": I just got done talking to a very large and reputable Porsche dealership in USA and the person told me that you can in fact "easily" swap out PCCB disc for Porsche steel (Turbo) discs,*BUT THIS CAN ONLY BE DONE IF YOU HAVE 390MM PCCBs.

The truck I'm looking at has options 1LX (Front brake discs for min. 20" wheels, yellow calipers (PCCB)) and 2EH (Rear brake discs for min. 19" wheels, yellow calipers (PCCB)) which means that the front discs are 410mm, not 390mm. PCCB 390mm front discs use the same caliper as the 390mm steel discs. Cayennes equipped with options 1LX and 2EH have different calipers from all other models. If you want to change to steel discs, then you need to basically change calipers, rotors, pads, knuckles and a whole other series of parts.*

I'm not 100% sure, but I believe that these are the following correct sizes (front/rear in mm): PCCB: 410/370 ; PCCB 390/358; Steel (Turbo): 390/358.

@911boost: did share this on Rennlist too...

That's what I've been assuming this would turn into. If the rotor sizes were the same, then I'd assume (without having read what you posted) that it was still 50:50 whether it was as simple as "swap rotors and pads".

Having to change out a bunch of stuff seems like a pain in the rear.

[911boost]

It is a completely simple swap on my RS, people do it all the time.

If the Brembo's or Giro Disks fit, it would be a simple swap for the Cayenne as well.

[Gus Berges]

Heard back from Brembo and nope, they don't have a disc that will fit a Cayenne that was originally equipped with 410mm front PCCBs. A very knowledgeable distributor for Brembo did quote a "kit" that includes adapters for 8 piston calipers for the fronts (with 16"/405mm iron discs) and 4 piston calipers for the rear (with 15"/380mm iron discs), pads all around, and brake lines for $10.4K (plus shipping). So switching "simply" from a 410mm PCCB disc to a 410mm iron disc only applies to 911s (997-992, most likely on the GT series).

Perhaps GiroDisc may have a solution, but will have to wait until at least Tuesday to get an official response from them.

[Gus Berges]

More info for future reference sake:

GiroDisc does not offer an option to replace the discs if the truck has the 1LX and 2EH options (410mm fronts and I believe 370mm rears) PCCB brakes.

Brembo too does not offer a direct replacement for the ceramic discs with the aforementioned options, but TPC Racing will in fact configure a kit consisting of hub adapters, Brembo GT calipers, discs, and pads for a total investment of ±$10.5K (plus shipping and labor).

Again, my hope is that this information proves to be useful in the future for someone considering the purchase of a CTT with PCCBs on it.

[Gus Berges]

Just to close this thread and hopefully be found later on for reference:

I sent ReDisc this picture and the answer I got back is: "A rough estimate based on the picture is that the discs look drivable/usable...however: According to the indicator, it can be seen that the thickness of the disk has already been reduced close to the permissible limit".

There are other things I can do to obtain the exact wear (weighing the discs), but truth be told, I'm "done" with this specific vehicle. It is quasi-incomprehensible to me that this $25K truck (2011 Turbo with 58.2K miles) has a sooner than later pending maintenance item that can easily cost between $8-$30K to bring up to spec. Can't say that investigating this vehicle and spending on a PPI has been a complete waste as I have learned quite a bit about PCCBs for 958s and in general, but I still struggle in trying to wrap my head around the fact that servicing this specific brake system could potentially cost more than the entire value of the vehicle (something that would not apply if it had iron rotors). I was hoping that the wear on these discs would be much less and I could have really purchased the vehicle.

This truck was never tracked and for the last 4 years in which ±20K miles has been added to it, it has been driven by a lady to do her shopping around town and taking kids to school (lady and her husband own/have owned any number of Porsches...).

For future reference sake, please investigate what version/size of PCCB are on the Cayenne you may be considering purchasing and don't be fooled into believing that these "last the lifetime of the vehicle". As to be expected and understood, mileage before replacement will vary greatly due to numerous variables, so determining how long they will last is a gamble at best. A very expensive gamble that is.

[herr_oberst]

I had never heard anywhere that CCB's were a lifetime brake system.

Is that something that Porsche, or Audi, or Ferrari or Ford or Chevy anybody actually say? Not trying to be snarky, I'm truly curious if this is a selling point of these brakes.

[Gus Berges]

The lifetime of PCCBs has an infinite amount of answers.... Some people claim that in a few track days they are toast, others claim hundreds of thousands of miles and no wear, others claim "should last the lifetime of the vehicle under normal use", and the truth lays somewhere all over that spectrum.

I've heard of owners of 958 Cayennes that have over 150K miles (±240K kms) on their trucks with these brakes and say "I have a lot of life left in them, and that is with the occasional cross country towing" and I've also heard of others saying that at 60K miles (±100K kms) the brakes needed replacement. Some say that PCCBs should last at least three to four times as long as regular steel rotors, but there are not as many posts about this type of guesstimation on how long they last versus mileage. If one were trying to be numerical about it, you'd think that overall long term running costs of PCCBs should be somewhat similar to the cost of iron based discs (I can see how PCCBs should be "slightly" more as they offer overall higher performance), but apparently the running costs are nearly 15 times as much (1,400% more is not a "slight" amount, especially when the base number is ±$1,200).

The truck in consideration just has more wear on its brake system than originally thought and is on the spectrum of the "not too long of a lifetime". Guess the previous owners enjoyed it at its full potential, thus the quasi-premature wear. And to think that this information came about from a "simple PPI request" that I almost did not have done as the truck had recently (couple of weeks) come out of the dealership from a complete maintenance schedule and extended warranty renewal.

The silver lining to all of this is that I avoided purchasing a vehicle that would have turned out to be a financial disaster. To all: never doubt the value of a PPI (assuming done at a proper place) and always learn as much as you can so you can gauge a situation by yourself instead of blindly trusting others. Caveat emptor has never been more applicable than in this situation....

[911boost]

The picture you posted of that brake rotor does not look bad. Just like you are saying on mileage, there are a ton of thoughts on the wear indicators.

As I mentioned earlier, someone looking for a $25K Cayenne prob needs to find one with steel.

[stevej37]

did you post this in the technical forum also?
Might get some better answers.

[Gus Berges]

Originally Posted by 911boost

The picture you posted of that brake rotor does not look bad. Just like you are saying on mileage, there are a ton of thoughts on the wear indicators.

As I mentioned earlier, someone looking for a $25K Cayenne prob needs to find one with steel.

I understand and respect your opinion regarding the wear indicators, but this time around I'm going to lean heavily on the opinion of ReDisc (even after they knew I was not going to send the discs to them) as they may (surely do...) have more experience regarding ceramic disc wear on many brands, Porsche just being one of them.

Regarding "someone looking for a $25K Cayenne", rest assured it's a self-imposed budget and definitely not indicative of anything else.

Anyone who is smart with their money would be wise to avoid any used Cayenne (or any other non limited edition Porsche) with PCCBs as the financial math simply does not add up. One thing is replacing PCCBs on a 958.1 Cayenne, another entirely different matter is replacing them on a Carrera GT.

At the end of the day, this post's main purpose was to inform others about the potential pitfalls of purchasing a 958.1 Cayenne equipped with 410mm front PCCB and document my findings of the journey I just went through. My hope is that someone may find the information useful. Certainly was for me.

[911boost]

It was by no means a dig on you, just that putting all new PCCB’s on a car worth $25k doesn’t add up, you’d be super upside down in it.

I have a GT3RS with them and bought a very lightly used complete set as a backup for less that the cost of just the fronts alone. However the math works out for me to do that…

This is a great thread and you have done a good job keeping it updated. You are right regarding the wear indicators, it’s almost like an oil thread, everyone has their opinions. I have seen some toasted PCCB rotors and it’s more about the surface condition I have always thought than the indicators.

[Gus Berges]

Thanks for your clarification and courteous response. You are 100% correct about being "super upside down on it" and it's the determining factor as to why I decided to look elsewhere. When I started looking at this truck, I had no idea about how to determine ceramic disc wear and it has been a learning experience that I wanted to share with the rest. I was always hoping that the wear was minimal, or in worst case scenario, to find an alternate solution that would make financial sense. If I had a GT3RS with PCCBs on it I'd be happy to replace them due to the inherent value in that vehicle. Guess I too could search for a lightly used set, but it's kind of complicated for me due to the shipping logistics in case what I receive does not match the description. At the end of the day, too much of a hassle (and expensive one) that is not worth it (for me) given the vehicle in question (958.1 Cayenne Turbo, not a GT car).

Again agree with you on the subject of wear indicators, but I'm going to trust my gut this time around and listen to ReDisc's opinion on the matter. As luck would have it, the local dealership just called me to ask me to come by their service department as they want to speak to me in person about their findings (not really sure why they just didn't send me the results...). I know the discs are not shot and don't require immediate replacement, but I also now know that they are not in "like new state" or have "tons of life left in them" thus a replacement is somewhat imminent during my expected ownership.

Again, the main purpose of the thread is to inform/educate others as this could potentially be a financially ruining experience for others.

[911boost]

Not a problem at all Gus, I have enjoyed this thread. Some of the guys on the other board can get pretty heated on this topic.