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My RS is the first PCCB car I've had, so I have no reference point for what's normal in terms of wear and dust.
I've noticed after aggressive drives that my wheel barrels (rear mostly) have significant buildup of pad material, but it appears as almost sand in color and consistency. And it's a LOT. Like, I can move it around and blow it out. I blew out the majority of it before thinking to take pics, but a few pics below just the same.
I changed pads today because I read all the threads about rear wearing at 2x rate to fronts, and suggestions to switch at ~ 50%, and my rears were almost exactly there. 7mm remaining. So I took the opportunity to measure and weigh the rotors too. 28.4-5 mm consistently, and right above 12.7 pounds, or 5760g.
I also searched and read extensively on measuring wear, and read the factory manuals about wear indicators and surface condition. My wear indicators are starting to show in the rear, but the surfaces are smooth as can be to the touch, with no blotchy patches or other notable imperfections (I appreciate that's an imprecise way to go about it, but it's what I have). The weight and thickness tolerances to new are so damn slim. I just don't know what's normal for a 16k mile car. I don't know its usage history, but presume it was tracked at some point, as most were. When I say I'm noticing the dust after "aggressive" driving, I mean near track conditions. My backroad drives are on super tight / twisty roads where I am threshold braking for 30+ min at a time.
There's a ton of conflicting information on the forums, so looking for some more reliable personal experiences here. Some threads say wear indicators aren't important, and neither is thickness, and that weight is the key. Others say it's surface smoothness / condition. I just don't know what to focus on.
So, is the dust normal? Do my rotors look to be in good shape despite wear indicators starting to show? Also, I checked the old pads to confirm they were the OE Pagid P40, and not P50 or some more aggressive compound.
EDIT - Is the stated weight on the rotor the weight when new, or the minimum weight ?? Very confusing.
Are you sure that's brake dust on your wheel barrels? I get that also but always thought it's from the mountain roads. I've cleaned off more of that then there is brake material so I'm thinking it's not brake dust.
The three wear circles on a ccb rotor are the three stages of wear. They become visible at different times.
I think the only way to really ascertain ccb wear is with that Proceq tool.
Are you sure that's brake dust on your wheel barrels? I get that also but always thought it's from the mountain roads. I've cleaned off more of that then there is brake material so I'm thinking it's not brake dust.
The three wear circles on a ccb rotor are the three stages of wear. They become visible at different times.
I think the only way to really ascertain ccb wear is with that Proceq tool.
I’m not sure, but have no idea what else it could be. I get it on a variety of roads. Agree the volume is kinda crazy. And you’re right; it is more than I would think could possibly come from the pads.
Originally Posted by ngng
They are not totally dustless, but will have significantly less dust than a steel combo.
So, my thickness is basically in spec for new, but what about the stated weight on the hat? Is that new or minimum? I get some regular (i.e. black) dust too. It’s this sandy stuff I’m baffled by.
Minimum thickness and minimum weight are always etched/stamped on these. Still the same way on the newer cars with CCB. When you replaced your front pads were they worn “wedge” like?
And as said above, PCCB are lessdust versus dustless.
I have had PCCB since 2003, and they do make some dust, but not sand.
Minimum thickness and minimum weight are always etched/stamped on these. Still the same way on the newer cars with CCB. When you replaced your front pads were they worn “wedge” like?
And as said above, PCCB or lessdust vs. dustless.
I haven’t replaced front because they’re nearly new, so don’t know about the shape. I’m doing rears now on the 50% advice. The rears were not wedged.
Maybe my question on the dust should’ve been “WTF is this sandy colored stuff?”
I knew that PCCB was less dust than steel. Substantially so, really. But it’s this sand that’s got me confused.
Hmm. Okay. Time for a control test. Gonna go find open straight interstate early am and do a bunch of test runs. @RAudi Driver made me second guess whether it might be road conditions. And I do drive the same backroad circuits around town, and they’re forest roads, so could be dirt.
We run Angelus Crest Highway in the early am. It's a nice pace and not much for braking as we are not going for all out best times. When I get home I've got a nice amount of sand inside the rear barrels. I take my air hose and blast it out. If it's not raining out I'll try to get a run in and film what I collect next weekend.
I have a Ferrari 458 with the first gen carbon ceramics(pretty sure similar to the Porsche 997 GT3RS PCCB's) and they definitely dust a lot more than my new GT4RS with the latest PCCB generation technology which literally has almost 0 dust.
I'm with the others here about the sand looking stuff. After 10 years with my car, I've never seen sandy dust. You say this dust is on the rear mainly. The fronts typically have more dust if it's coming from the brakes. Your situation is pretty odd.
For ceramics they will put off some black dust though, particularly on a good run with harder braking.
Just a thought.... is this your first car with black wheels? My car has black wheels and PCCB's like yours and I get that sandy residue as well. It's different than brake dust and I've always just assumed it's from road conditions. Maybe it just wasn't as noticable with lighter colored wheels? Again, just a guess on my part.
Just a thought.... is this your first car with black wheels? My car has black wheels and PCCB's like yours and I get that sandy residue as well. It's different than brake dust and I've always just assumed it's from road conditions. Maybe it just wasn't as noticable with lighter colored wheels? Again, just a guess on my part.
Yes, first non-track car with black wheels. But my track cars were also steel brakes, and not driven on roads. What’s strange is the residue is so consistent. I guess it’s not really a problem if my pads / brakes are wearing at a normal rate. Just very curious.
@Finlander Definitely only really noticeable on the rears, but my thinking was that since the rears on 997.1GT are known to wear much faster than fronts, that might be the reason (if this is related to brakes at all).
03-10-2024, 09:15 PM
PCCB Wear / Dust ?
