Vehicles capable of high velocity require brakes with mighty stopping power, or the driver might find himself on the wrong end of the adage, “You can’t change physics.”
The S65 AMG introduced by Mercedes-Benz USA at the Chicago Auto Show here has some of the largest-diameter brake rotors available on a production sedan.
But they are a comparatively conventional cast iron/aluminum composition – not the exotic carbon-ceramic material that markedly enhances braking power and durability.
Mercedes SLR carbon-composite brake disc.
More advanced ceramic-brake systems consist of brake discs formed from oven-baked ceramic material reinforced with strong, lightweight carbon fiber. Advantages claimed for carbon-ceramic braking systems include noticeably enhanced performance, reduced unsprung mass and markedly extended service life. (See related story: Designer Braking)
Porsche AG and Ferrari SpA are proponents of race technology-inspired carbon-ceramic braking systems that were the talk of the industry just a few years ago.
But it was Mercedes that claimed in late 2000 to be the world’s first auto maker to launch carbon-ceramic brakes for a production car, the limited-edition CL55 AMG F1. None of the 55-unit run was imported to the U.S. The so-called “C-brake” rotors were fitted only on the front axle.
The new, high-powered S65 AMG would seem a natural candidate for the high-tech brakes. But Rob Allan, AMG product manager, says the car retains its relatively standard – albeit supersized – braking technology because Mercedes is not convinced carbon-ceramic brakes are right for most of its models – even the high-performance AMG versions.
Only one current-production Mercedes sports carbon-ceramic brake rotors: The hyper-exotic $450,000 Mercedes SLR.
“In our world, owners use their (AMG) cars as everyday drivers,” Allan says, noting a prime customer-satisfaction issue: Unless fully warmed, the carbon-ceramic brakes tend to squeal excessively, and noisy brakes do not invoke an image of high quality.
Equally important, Allan says, carbon-ceramic brake systems remain prohibitively expensive, thanks to low production volumes and tedious “strict production methods.”
He estimates the cost to outfit a car like the S65 AMG with a carbon-ceramic brake system would be $7,500-$10,000.
Ferrari offers carbon-ceramic braking systems on several models and Porsche made its Porsche Ceramic Composite Brakes available for all ’05 911 models. The PCCB system previously was offered only on the 911 Turbo and select special 911 variants.
AMG’s Allan says, “It’s only a matter of time,” before carbon-ceramic brakes become a more mainstream proposition.” But for now, Mercedes thinks more conventional components are the best proposition for the type of driving in which typical customers engage.