Carbon-ceramic brakes to become cost-effective for enthusiasts?

[Nick Koan]

They are saying the production cost of the carbon ceramic brake rotors could go down from a current $665-$2660 range down to ~$465 with a new process. Of course, flat steel rotors probably only cost $20 to manufacture. Probably still a bit expensive, but its encouraging to see prices coming down.

But they are touting better life, heat dissipation, stopping power and unlike carbon ceramic rotors, no warm-up time.

http://www.autoweek.com/apps/pbcs.dl.../FREE/61218009

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Carbon-ceramic brakes could become affordable for enthusiasts

By TONY LEWIN | AUTOMOTIVE NEWS

AutoWeek | Published 12/18/06, 10:53 am et
Carbon-ceramic brakes built a glamorous reputation in Formula One racing, creating vivid images of discs glowing red during hard braking at the end of long straightaways.

Their high cost limited them to exotic performance cars. But carbon-ceramic brakes are now available on cars priced as low as 60,000 euros (about $80,000 at current exchange rates). And a new manufacturing process could make them affordable for even budget-minded enthusiasts.

The technology has been slow to spread to production vehicles since it was introduced in racing 15 years ago. Porsche first offered a carbon-ceramic brake option on the 911 GT2 in the late 1990s, followed by the more mainstream 911 Turbo in 2000.

Today, carbon-ceramic brakes are optional on all Ferraris, most Lamborghinis and Porsches and the Bentley Continental GT Diamond. These cars are priced above $133,000.

The percentage of buyers choosing this option ranges from more than half for Ferrari models to 6 percent for the Audi RS 4.

For enthusiasts, the performance-driving benefits -- less weight, better handling because of reduced unsprung weight (the mass of the body and components not supported by the suspension), durability and fade resistance -- make the high price worthwhile. But if the price falls dramatically, carbon-ceramic brakes also could appeal to more thrifty buyers.

Carbon-ceramic brake discs last four times longer than conventional steel discs, so owners are unlikely to replace carbon-ceramic discs. Brake pads last longer on the carbon-ceramic systems, too. But at $15 to $20 a disc for steel discs and $665 to $2,660 a disc for carbon-ceramic, owners cannot recoup their cost on the more durable system.

The big step

SGL Carbon AG, of Wiesbaden, Germany, and Audi AG are trying to reduce manufacturing costs for carbon discs by moving from batch production to a continuous process.

Since last year, Audi and SGL have been working to establish automated production, reported the German daily newspaper Frankfurter Rundschau.

"The cost of a disc will come down to 350 euros (about $465) with the new process," says SGL Carbon CEO Robert Koehler. He would not disclose details of the technique.

Audi declined to comment on the technology.

Antonio Ferreira, manager of European component forecasts at CSM Worldwide in London, is skeptical of carbon's broader market potential, even with reduced costs.

"You would need huge volumes to get the price down," he says. "Suppliers would have to come to a two-digit price (per disc). Nothing else is feasible when a complete braking system is not even into three figures."

At Italy's Brembo, which has a 60 percent market share in top-end sports- and luxury-car brakes, carbon-ceramic is still in a "quasi-prototype" phase, said Roberto Vavassori, business development director.

Light and durable

But Vavassori is optimistic, saying the technology's lower weight and long life could become as important as its extreme performance.

"We haven't seen the full potential for carbon brakes yet," he told Automotive News Europe. "They can save 40 kilograms (88 pounds) on an extreme car where mass is important. And in the future, we may see wider adoption in other segments, too."

SGL is working with Porsche and Audi to develop ready-made auto components.

The key to lowering costs is simplifying production.

"It's not mechanical but chemical," said Brembo's Vavassori. "We start from powders and end up with a lightweight disc, but an expensive one."

Antoni Sznerch, business development director of United Kingdom-based Surface Transforms, says versions of the carbon brakes for cars must be even more sophisticated than those on airplanes or race cars.

"The process is similar to how nature creates coal and extremely hard substances like diamonds," says Sznerch, whose company makes SystemST carbon brakes. "Some processes are lengthy, demanding three weeks in the chamber to go through a thermal cycle."

How it works

Carbon-ceramic brakes use the same principle as ordinary disc brakes. Stationary twin calipers clamp onto both sides of a disc rotating next to each wheel of a car, slowing it by friction.

The energy of the car's momentum is transformed into heat at the point of the friction, so brakes can get extremely hot. Carbon-ceramic brakes use carbon fiber and ceramic materials that are stable at temperatures that would make steel discs bendable. Performance doesn't diminish, leading to fade, with repeated use.

Carbon-ceramic brakes also typically use larger calipers to spread the clamping force over a wider area, improving braking performance.

Race-car brakes must be warmed before they work properly. For passenger cars, carbon-ceramic brakes must be fully effective immediately. The discs and brake pads are more sophisticated, with carbon fibers arranged to strengthen the disc and conduct heat away from the surface.

Bentley: Demanding case

Weighing 5,258 pounds and capable of 198 mph, the front-engine Bentley Continental GT has "almost certainly the most demanding braking task of any production car," says Brian Guash, Bentley's director of chassis, powertrain and motor sports.

Midengine cars such as the Bugatti Veyron have it easier, Guash says. Their weight distribution means that all four wheels can share more of the braking effort. On the Continental, the front brakes do most of the work.

The Continental GT already had the biggest brake discs in the industry at 16.2 inches. "Now we've broken our own record, with a 420-millimeter (16.8-inch) carbon-ceramic disc, which is half the weight and gives us lower unsprung and rotating masses," Guash says.

The ceramic brakes also have superior fade resistance and improve steering precision, he says. Pad life has tripled, and discs should last the life of the car.

[MPREZIV]

I'll start saving now!