Let’s admit it, PCCBs are cool. The substrate is high tech, they look awesome, there’s no brake dust, and finally at under 9k for the set, they are something of a bargain in the Porsche world. That was why i had them spec’d on my 718 Spyder until the last minute when I changed my order

Here are the reasons, some i think well considered others quite speculative:

Dynamic performance: both are great
After comparing a pair of 991s with and without, I didn’t notice any difference dynamically. If you have ever driven on track tires vs street tires, you perceive a dynamic difference almost immediately, the stiffness of the sidewall, the turn in, bite etc. I can’t say i noticed any dynamic difference between the braking systems There was a difference in braking feel but which is better I think would probably be personal preference. Granted, I wasn’t pushing the cars to near 9/10ths but the fact that many people I respect swear by iron rotors for their track days makes me guess that there isn’t a significant deviation in performance between the two rotor systems

I should also add a lot of the good info i read from many of the knowledgable people on this forum seems to concur with the above. But sometimes you have to find out for yourself

A pebble in my shoe
I have gotten gravel stuck in between my brake rotors on a couple of Porsche’s I’ve owned. The noise alone is enough to drive you nuts. If that noise also signaled you now have to replace a $10,000 pair rotors I think I would go apoplectic. Of course, the likelihood of this occurring is slim but It does happen and having to grit my teeth every time I spray some gravel is not something I really wanted to contend with.

Strut tower issue paranoia
Hopefully, the dreaded 981 GT4 strut tower issue Is a thing of the past. And granted, it appears to be an issue limited to very few 981 series GT4 cars. That said, I was getting full on paranoia reading some of the horror stories on this site which I’m sure many of you can identify with. While I’m not a mechanical engineer, it occurred to me that greater mass absorbs more energy, so greater mass at the wheels should theoretically do a better job of absorbing the shock wave of say a pothole before that energy is transferred up along the strut to the strut tower. I cannot say if it would make a difference but I think it’s a reasonable theory and another reason why I decided to go with iron rotors.

Conclusion
I still think the PCCBs are very cool and had I decided to get a color scheme conducive to yellow calipers the decision would have been even harder. That said, the iron rotor braking system on this 718 Spyder, is sublime. Pedal feel is perfect as is stopping power. While i haven’t driven hard enough to comment on fade or heat cycles, i have a feeling these brakes will be a reliable partner on track and street alike.

Regardless of the rotors chosen, i suspect all of those who ordered a 718 Spyder or GT4 will be quite impressed. Porsche has been flirting with perfection in the realm of sport car manufacture for a good many years. The 718 Spyder and GT4 bring their mid engine platform that much closer.

 

I had similar thoughts. PCCB have many advantages, but the combination of damage fears, replacement costs, and the fact that they seem to be prone to squealing, made me decide against them. I noticed that PCCB squealed in nearly every video review of a GT4 or Spyder.

I know some people say their PCCB don’t squeal, but it seems common enough, and Porsche regards the squeal as normal. Having them squeal like that all the time in city driving would be irritating.

I never thought of the strut tower issue in this decision, and don’t know if brake choice would make any difference. I hope it’s resolved now.

 

I’ve had CCBs on my old Z06 and they were great. A great upgrade over the already good steel brakes. However the cost for an entire replacement set on that car is less than the cost of one PCCB. The economics and value are far different and it doesn’t make as much sense to me in the Porsche world. For a street car I think PCCBs are fine, given they’ll last the lifetime of the vehicle and you get the benefits of low dust and low maintenance. On a track car I would go steels or swap out PCCBs with steel replacements. They’re just far too expensive.

Regarding the strut tower failures, I recall some 991 GT cars have had failures too, though less frequent. I hope Porsche has resolved for the 982. For brake selection and it’s relationship to this issue, I am not a mechanical engineer but I would have assumed the opposite to your rational. Brakes are are not springs and do not absorb force through suspension travel. Brakes are unsprung weight and more unsprung weight means more force is transmitted through the suspension and to the body/strut tower through impacts. I think of it like a hammer, a 20lb hammer is going to drive more force into an object than a 10lb hammer at the same speed.

 

Completely opposite to the hammer analogy, the brake isn’t being swung, it isn’t the source of the energy. Rather it’s receiving the energy, damping/dissipating it through its mass and transferring the excess or unabsorbed energy up through the strut to the tower. Think of ballasts on a bridge, while not a “spring“, their mass is designed to absorb/ dissipate energy.

All things being equal, more mass at the point of impact provides more damping/dissipation and less transference. That said, I can’t say if the difference in mass between Irons and PCCBs would make a difference at all. Given that few cars suffered from this, it’s likely that there was some inherent weakness with the tower itself on certain random cars.

 

After AXing a 991 GT3 with PCCB's I could never go back to steelies.

 

OP, good decision for all the right reasons. I'd add to the list the iron's better fade resistance due to more mass => higher capacity for heat absorption.

 

While it’s true the irons have more heat capacity, the benefit of PCCB is better heat dissipation due to a combination of permitting higher temperatures and larger surface area. Thus under sustained repetitive braking (eg. track), PCCB would be more fade resistant than iron because it can dissipate a higher wattage without exceeding its thermal limits.

If you aren’t bothered by the cost of replacement, PCCB is definitely better for track, due to higher heat dissipation and lower unsprung/rotational mass. Having lots of money would also make the worries of damage and replacement costs also go away.

 

I spec pccb on all my cars because I'm too lazy to clean the wheels.

 

Turn everything upside-down: The car isn't on the road and moving around. The road is on the car and it's the road that's moving around.

Model this not as two bodies (strut tower and the wheel/brake assembly) rigidly connected but as two bodies connected by a spring(a damped spring if you want to get fancy) where one body's mass is 2-3 orders of magnitude greater than the other.

Also realize that a bump in the road doesn't apply a fixed force to the car. It applies a fixed deflection requirement and a fixed acceleration requirement for traversal of the bump under the assumption that you want your tires to stay in contact with the road (and that is the working constraint for suspension engineers.)

 

If PCCBs lived up to those initial claims of lasting a lifetime of the car (street & track), I'd spec them. Then again, I've never heard anyone tell me at the track or anywhere, "yea, that guy in the other car (same model) had PCCBs, he beat my time!" I think Girodiscs and the right pads would do the trick. Agree @Underblu , the stone issue destroying the CCBs is also pretty unnerving.

 

9 grand buys a lot of car washes

 

I have PCCBs on my 991.2 C2 and, in two years of use, I don't ever recall them squealing. They are sublime.

God bless,
TT

 

I’m both cheap and lazy so I have irons but I also hardly ever brake, lol...

 

I am getting PCCB's on my Spyder, every thing I found during my research supported the decision...

I could not find a single strut tower incident on the 981 that wasn't explained by an external force or off road incident... if you know of a verifiable example that has absolutely no history associated with it I would welcome a link to the facts about it.

A little light reading:

https://rennlist.com/forums/718-gt4-spyder/1174590-strut-tower-issue-from-981-resolved-on-718-a.html#post16305160

 

I have the steel brakes on mine and they squeal too....