MagicRat

Steels will provide that more than PCCBs. I have one car with each. It’s not a massive difference but ceramics definitely require a gentler touch. They’re in no way grabby, just more aggressively progressive if that makes any sense. Like dropping a ship’s anchor into 50 feet of silt.

Ira Blumberg

I had the same thought when specing my 991.2 C4 GTS. I wanted the lightest possible configuration. 4wd was a necessity as I will be moving to a snowy climate, but I wanted all other weight removed. I deleted the sun roof and added the PCCBs. My only compromise was the 18 way seats which I'm sure add a few pounds, but the fit me wonderfully.

I never compared the ceramic brakes to steel. I will say that the ceramic brakes are amazing as brakes. At this point it is almost dangerous for me to drive other cars as I am so fully used to braking late and having the car just STOP. I have owned lots of high performance cars before including Corvettes, a Nissan GT-R, 2 C63s and an M4. Nothing has ever come close to the braking performance of the C4 GTS with ceramic brakes. I have not been to the track with it yet, perhaps someday (although I generally prefer driving schools where I can risk someone else's $150K+ car rather than mine). Regardless, even just for street driving, I have no regrets and just joy for the ceramic brakes.

ace37

Keep in mind for a similar car with the same suspension and ABS system, braking in terms of distance to stop has nearly everything to do with the tire performance. CCBs and steel brakes can lock the tires up just as well as one another. System weight, cost to maintain, feel, intangibles such as personal preference, and thermal performance are all reasonable to consider, but the single stop 60-0 and 100-0 times or distances are going to be equivalent.

If the cost is genuinely not a factor, by all means get them. A lot of folks prefer the feel and like the very low brake dust benefit, and they are lighter. CCB replacement costs are high (expect on the order of $10k per axle from the dealer) and have a significant impact on the long term cost of tracking the car. But for a street-only car you might never have to replace them, so it could reduce maintenance costs for you.

The CCB weight reduction is significant. It is not at the outer edge of the tire like wheel and tire weight, so it is not likely to be as noticeable as the tires on your BMW. Rotational inertia is proportionate to the radius squared, so being out at the edge makes much more difference than being inward towards the middle. But it is a weight reduction and not a trivial one, and you can always get a lightweight set of wheels as well as CCBs - it's certainly not an either/or scenario if you have an open wallet.

On motorcycles lighter wheels make a big difference and are quite noticeable. That said, high performance motorcycles are 300-500 lb machines and the gyroscopic effect has a huge role in steering and cornering, so the effect is dramatically larger than on a car that weights ten times as much and never really leans unless you're in trouble. Also there are quite a few cheap targets for weight reduction if that's what you want. Sunroof delete, lightweight battery, skip options like PDCC and RWS, change to 4 way seats or buckets, get the basic stereo or delete the stereo, delete the rear seat and sound insulation, change to RS door cards... when you make a lot of small changes, together they'll make a very big difference. But if you go too deep down the rabbit hole you'll essentially have a race car without a cage, and perhaps something like an RS, a Cup car, or a Lotus Exige would have been a better choice.

Pep!RRRR

Good discussion above. The CCB are so large that they preclude the use of 19” wheels. So an alternative approach for minimizing weight would be 19” lightweight wheels, two piece steel rotors with aluminum hats, coupled with grippy tires.

Need4S

+1. Brake rotors are essentially means to turn kinetic energy into heat. CCBs have better thermal characteristics than steel brakes, meaning they can more efficiently convert kinetic energy to heat and dissipate it, especially in repeated heavy braking. The differences in stopping distances in normal operation are likely minimal, but as noted above, there can often be a different feel. Note that you could get brake pads for steel rotors that may have similar high torque grabby feel with lighter pedal pressure, but the compound might give up performance in terms of high heat fade. Pad materials have an operating temperature range, and choosing the right range for the intended use is key. That’s why people use “track” pads there but a different compound for street. You “could” use the track compound in street driving if you don’t mind extra long stopping distances when their temps are below optimum. Personally, I wouldn’t, as that could be dangerous, and such compounds are often noisy as well. If you use race pads on the street, they might never get hot enough to safely stop the car in street driving. The temp range is broader with CCB rotors, which is why they work so well in more varied uses.

digits

I know the thread is about handling, but also consider this disadvantage of PCCBs: they are BIG. There's not much room between the calipers and the rim.

Three times in the past year, I've had a pebble become lodged in the gap - it scores the inside of the rim and makes horrifying grinding sounds when it happens.

Here's my reaction the first time it happened: https://rennlist.com/forums/991/9910...-911-made.html

KM1959

I think anyone short of a test driver doing a back to back comparison could actually determine a handling advantage and even then I think it would have to occur on unsettling pavement. Their advantage is clearly for track use and inherent fade resistance. On the street, it's for minimzed brake dust and for looks. If you drive in the mountains, you'll appreciate them on long downhils. Finally, they simply look badass. If I were spec'ing a car, they'd be on it, no doubt.​​​​​
​​​​

Hurricane

...

George from MD

I highly doubt any one of us is going to feel a handling difference- on the street or track. Kimi, Lewis, Juan Pablo yes. Joe, Ed, Debbie or other typical 991 owner or DE participant. Please. Cut me a break.

ipse dixit

Having driven a 991 GT3 with CCBs and Iron rotors, back to back, on the same day, same track, multiple times, yes, I can tell a difference.

And, no, I have no F1 races on my resume (nor F2 or F3 for that matter). I can barely heel-and-toe on my second-hand S2000 ...

911boy

Handling or braking?

R_Rated

Will make substantial difference in around town feel. I’d wager 0 to 60 times down too. Every car with a change to lightweight wheels for me has manifested this. Even in a numb Volvo. The cars where I’ve also done lighter, 2 piece rotors felt like I lightened the car by weigh more, steering improved, braking and the whole car felt lighter on its feet. This is worth the price of admission for a street car IMO.

Pun intended if you can find it.

ipse dixit

Handling.

But braking differences become more noticeable the longer the session is.