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Curious as to what the content would be were the pads swapped at 50% wear. That seems to be what a lot of people think needs to happen. These numbers seem to suggest it isn't too much to worry about, perhaps.
What exactly are we looking at there? You measure each rotor in three different spots? At three different times? Can you expound please?
PCCBs come with new/minimum specs on the rotor hat in three places. You use a tool to measure on those places, there is a laser that aligns to a marker where you test. You are measuring remaining carbon content, the minimum number is just that, new is what they measured when produced.
Hmm, counter-clockwise would put more load on right side of car (I'd expect the right front pads to be more worn than left). I'm not sure if it applies to PCCB rotors, but on Iron rotors and pads the wear starts slowly and accelerates as you get closer to gone. So, when you see something like 28% thickness left on pads and rotors, you actually have far less on a time basis (or number of track days left).
Stands to reason that the rotor wear for PCCB wouldn’t be linear either. The carbon fibers are there to dissipate heat. If there’s only 28% of them and the heat is the same, something has to give.
Curious as to what the content would be were the pads swapped at 50% wear. That seems to be what a lot of people think needs to happen. These numbers seem to suggest it isn't too much to worry about, perhaps.
That’s a good question. I’ve consistently been told that to save the rotors, you should change pads at 50%. Given pads cost less than 5% of what the rotors cost, feels like good insurance.
Stands to reason that the rotor wear for PCCB wouldn’t be linear either. The carbon fibers are there to dissipate heat. If there’s only 28% of them and the heat is the same, something has to give.
I don’t disagree. My guess is on the street they’d last for a long time. I’ve got the pair to this front left still on the front right, I’ll replace that soon. Long story, I got a set of 3 replacement rotors from a buddy, two rear, one left front. Those all measured 80-95% of new. So if the front right is like this front left, it is probably time to swap. This car gets tracked a ton.
Okay, some hard data on PCCB and track use. These are numbers off of a 2016 GT3. Approximately 70 track days, most by the head PCA instructor here (which I actually think means he isn't super hard on brakes, he's a really efficient driver and very talented). He'd gone through two sets of pads before I bought the car from him, the car was on the third set of stock pads. And by "gone through" I mean running them until the wear warning light came on. Car has 23k miles, 60 days by him and 10 track days by me when these came off. We took three off because I had three replacement rotors to swap on. Front left is getting there but still within spec according to the dealership. I'd expect front right to be similar. Interestingly there is more wear on the left than the right, we have mostly counterclockwise tracks here, I'm wondering if it is related to that.
Thanks for sharing.
Hopefully this would put to rest some of the rather unfounded belief here on RL that PCCBs are too brittle and unsuited for regular track use.
Hopefully this would put to rest some of the rather unfounded belief here on RL that PCCBs are too brittle and unsuited for regular track use.
I think that belief is grounded in 997 and earlier rotors. This seems to confirm stories of these 918-era rotors being hammered on by Porsche factory drivers for thousands of track miles.
[QUOTE=dsteding;17966185]Okay, some hard data on PCCB and track use. These are numbers off of a 2016 GT3. Approximately 70 track days, most by the head PCA instructor here (which I actually think means he isn't super hard on brakes, he's a really efficient driver and very talented). He'd gone through two sets of pads before I bought the car from him, the car was on the third set of stock pads. And by "gone through" I mean running them until the wear warning light came on. Car has 23k miles, 60 days by him and 10 track days by me when these came off. We took three off because I had three replacement rotors to swap on. Front left is getting there but still within spec according to the dealership. I'd expect front right to be similar. Interestingly there is more wear on the left than the right, we have mostly counterclockwise tracks here, I'm wondering if it is related to that. [QUOTE]
Has the car needed the wheel carrier maintenance with that many days?
Has the car needed the wheel carrier maintenance with that many days?
Yes, we rebuilt the hubs front and rear this winter. Fronts didn’t necessarily need it but it the front right was done when we CPO’d it (there was some minor hub damage from a loose CL nut) so I did the front left when we did the rears.
Okay, some hard data on PCCB and track use. These are numbers off of a 2016 GT3. Approximately 70 track days, most by the head PCA instructor here (which I actually think means he isn't super hard on brakes, he's a really efficient driver and very talented). He'd gone through two sets of pads before I bought the car from him, the car was on the third set of stock pads. And by "gone through" I mean running them until the wear warning light came on. Car has 23k miles, 60 days by him and 10 track days by me when these came off. We took three off because I had three replacement rotors to swap on. Front left is getting there but still within spec according to the dealership. I'd expect front right to be similar. Interestingly there is more wear on the left than the right, we have mostly counterclockwise tracks here, I'm wondering if it is related to that.
No doubt the exact wear depends on the driving style, type of track, etc.: my PCCB were toast after 4,000 track miles, which is about 25 track days, but it was driven by an "advanced group" driver, on a track with alot of hard braking zones (Sebring). No doubt, if Daytona were driven more, or it was driven softly, the PCCB would've lasted longer. . .
No doubt the exact wear depends on the driving style, type of track, etc.: my PCCB were toast after 4,000 track miles, which is about 25 track days, but it was driven by an "advanced group" driver, on a track with alot of hard braking zones (Sebring). No doubt, if Daytona were driven more, or it was driven softly, the PCCB would've lasted longer. . .
As a point of comparison, do you have an idea of how many iron rotors the car would've gone through with the same number of track miles and days at the same track (Sebring)?
As a point of comparison, do you have an idea of how many iron rotors the car would've gone through with the same number of track miles and days at the same track (Sebring)?
Yes, I'm also in the advanced group, and I'm about to wear out my front rotors on the Girodisc conversion. They have lasted me 24 days so far. . . I expect another 2-3 days out of them. . .
As a point of comparison, do you have an idea of how many iron rotors the car would've gone through with the same number of track miles and days at the same track (Sebring)?
Good question.
My take on it is that PCCB and iron aren't all that different in total cost of ownership across a really big set of track days. It's a matter of whether you'd prefer to pay 25% four times or 100% one time (or something equivalent). Of course many would never get to the point of needing to replace the PCCB. And more importantly, the performance of the PCCB is superior to the iron the whole way along. I believe PCCB should be viewed as a "performance option" and performance comes with both benefits and costs. If it's only about the track the decision can be made on those terms. The problem is that for the most part people are making the choice in some significant part about street use, resale, hassle, etc. And in that case PCCB adds some annoyance. Again, just my take.
Separate but related I'm seriously exploring going with Surface Transforms on my 992 GT3 Touring. I believe this may well be the best of all worlds. However the cost is not trivial. YOLO, ADM, no ADM, PTS, no PTS, blah blah. Sinatra - did it my way.
Separate but related I'm seriously exploring going with Surface Transforms on my 992 GT3 Touring. I believe this may well be the best of all worlds. However the cost is not trivial. YOLO, ADM, no ADM, PTS, no PTS, blah blah. Sinatra - did it my way.
Cost aside, there is also the hassle of how to get them resurfaced. You have to put the car on jack stands, remove the wheels and brakes and rotors, and mail the rotors back to ST in Europe and then... wait. And wait. And wait. All the while, your car is underivable. Unless you have another set of rotors/pads/calipers (if needed) to go on in the interim. Not many people do. On top of that, some people don't have their own private garage where they can work on their cars like this. I imagine the majority of owners would bring their car to a shop and have the shop handle it. But then you're paying the shop to store your car for a few weeks while you wait for the rotors to come back in the mail.
My take on it is that PCCB and iron aren't all that different in total cost of ownership across a really big set of track days. It's a matter of whether you'd prefer to pay 25% four times or 100% one time (or something equivalent). Of course many would never get to the point of needing to replace the PCCB. And more importantly, the performance of the PCCB is superior to the iron the whole way along. I believe PCCB should be viewed as a "performance option" and performance comes with both benefits and costs. If it's only about the track the decision can be made on those terms. The problem is that for the most part people are making the choice in some significant part about street use, resale, hassle, etc. And in that case PCCB adds some annoyance. Again, just my take.
Separate but related I'm seriously exploring going with Surface Transforms on my 992 GT3 Touring. I believe this may well be the best of all worlds. However the cost is not trivial. YOLO, ADM, no ADM, PTS, no PTS, blah blah. Sinatra - did it my way.
From my experience, as described above, PCCB and Girodisc iron replacement rotors last approximately the same amount of time on the track. Now, on your GT3 Touring, I'm sure it will be a different story, assuming that you do not significantly track your car. From my experience, there is only one advantage to PCCB: it stays cooler, so your tires don't overheat as quickly on the track. (Another reported advantage is weight savings, but I'm a heavier guy, and an extra 20 lbs isn't going to make a difference to my track driving.) The professional Porsche manufacturer race teams all use iron rotors, so I'm told by a former head mechanic on the team.
02-10-2022, 08:34 PM
