By Aaron Bragman on Mon Aug 25 23:07:00 GMT-06:00 2014
I just finished a week in a $177,000 2014 Porsche Cayenne Turbo S, the German sports-car maker's top-of-the-line, super-fast twin-turbo V-8-powered SUV. It's a remarkable machine — sleek, ridiculously quick, crazy expensive and possessed of one quality that drove everybody who rode in the machine absolutely nuts. The brakes squealed like a poorly maintained diesel city bus.
The noise made every stopping event more about figuring out how to modulate the brakes to prevent noise instead of enjoying the amazingly firm and fade-free properties of the huge stoppers. That's not an attribute any car should have let alone a new six-figure one.
What caused the problem? This particular Cayenne had carbon ceramic brakes — a special high-performance option that replaces the common steel rotors and metallic pads with special cast rotors that use a proprietary composite, a mixture of resins, fibers and powdered metal. These special rotors are far better at dissipating heat at racetrack speeds, enabling lap after lap of extremely strong braking that would toast normal brakes.
On race cars and some high-performance sports cars that see a lot of high-speed, harsh-duty use, they make sense. And they work amazingly well on the street, too, with strong, fade-free braking time and again. But they work best when they're hot, and these brakes come at a cost that isn't listed on the window sticker — noise, and lots of it.
The fact that the brakes on your average family sedan don't make a huge amount of squealing noise in everyday use is actually something of an engineering miracle. Think about it — the reason you stop when you hit the brakes is due to friction, the rubbing of the pads on the rotors with significant force brings you to a halt. The formulation for brake pads to enable that to happen without crazy amounts of squeal is equal parts experimentation and materials alchemy. But for carbon ceramic brakes, noise is often secondary to stopping power and repeatability. The engineers don't seem to mind that when used under more relaxed street conditions, these pricey brakes make more noise than the jalopy next to you at the stoplight.
The problem becomes this: Why are these racing brakes even offered on a Cayenne, a heavy five-passenger SUV meant more for ferrying Kardashian-class socialites to a mall than setting lap records at Road America raceway? Ponying up the $8,840 for the carbon ceramic brake option is only likely to bring dissatisfaction and trips to the dealer to try and quell the squeal.
The Cayenne isn't the only car guilty of such options-list silliness — all sorts of cars are now offering these brakes as an extra-cost option, but most limit them to special track-oriented models, like the upcoming Z07 Performance Package on the already-track-oriented 2015 Chevrolet Corvette Z06. Editors in our Chicago office recently tested the new Jaguar F-Type R Coupe and experienced the wrong kind of looks from cars in gridlock as the brakes squeaked on a lengthy commute.
Our recommendation: If you drive your ultra-performance car on the streets more than you do on a racing circuit, skip the expensive carbon ceramic brake option. They may look cool and offer some fun bragging rights at the local Cars & Coffee, but they really are racing brakes and are only likely to cause auditory distress and buyer's remorse.
Cars.com photos by Aaron Bragman
Detroit Bureau Chief Aaron Bragman grew up in the Detroit area, comes from an automotive family and is based in Ann Arbor, Mich. Email Aaron