Porsche Brake Squeal Push-Back Says The Squeaking's Good
What noise should a Porsche make? If it's under hard acceleration, you'd probably expect the roar of a flat-six, but at lower speeds your six-figure sports car might be making sounds more like a squeaky mouse. Porsche, though, would like you to know that the squeaks are normal.
At least, that's the purpose of Porsche's latest video, "Brake Squeal Explained." Describing the issue as "one decibel-driven disturbance that has been misunderstood for far too long," it challenges the assumption that there's something wrong or even ineffective about squeaking or squealing brakes. Indeed, the automaker argues, it's really a sign of just how powerful they are.
"Brake squeal occurs when the energy of motion is converted into heat and minute vibrations," Porsche explains in the video, "which then dissipate through the brake system." In effect, the brake rotor is acting as a speaker. The combination of large rotors – required to, well, bring the car to a halt – and sizable brake pads mean that the pressure of the latter on the former can be inconsistently applied. That adds up to the unwanted vibrations.
Porsche isn't just counting on explanations to settle the issue, mind. The automaker also puts counterweights onto the calipers, which can cut out some of the frequencies that make it through to our ears. Nonetheless, it's not going to be fully effective in cutting out all squealing.
The unspoken subtext would certainly appear to be that sports car owners simply don't know what to expect – and thus what's "normal" – from their performance brakes. Carbon fiber brake systems are known for their propensity for excess noise, particularly at slow speeds such as when you're pulling up to a stop sign or traffic lights. However, it's not limited to those, and more mainstream brake systems can certainly exhibit the same thing.
Porsche's suggestion is that, if you really are worried about the noise, you should take the car in to have it checked out by a service technician. All the same, it insists that – regardless of noise – its brake systems are four times as capable as is needed to bring even its most powerful engines to a halt. Considering that includes models like the 420 horsepower, 189 mph capable 911 Carrera 4S, that's probably a good thing.
What will be particularly interesting, of course, is when Porsche starts making significant use of regenerative braking. That'll arrive on the Porsche Mission E, its all-electric sedan and a rival to Tesla's Model S; although it'll have regular brakes, it'll also be able to slow the car by effectively flipping the wheel motors into reverse and turning them into electricity generators, topping up the battery.