Filed under: Plants/Manufacturing, Tech, Audi
Carbon-ceramic brakes on their way down to the peons
The sight of a race car streaking into the darkness, brakes aglow as it slows for the next corner, is one of those incredible images that just sticks with you. Those massive carbon-ceramic rotors can take a lot of abuse and their light weight and durability have made them a racing staple for more than 15 years now. Street cars, on the other hand, have been slow to adopt the technology. Although their superior performance is unquestionable, the high cost of carbon-ceramic brakes has made them pretty much exclusive to exotics and supercars.
Porsche was the first to use them on a street car when they fitted them to the "widowmaker" GT2. Soon after, they found their way onto the "regular" 911 Turbo as well. Now you can get carbon-ceramics on any Ferrari, most Lambos and Porsches, the Bentley Conti GT Diamond and the Audi RS4. But whereas half of Ferrari buyers splurge for the upgrade, only 6% of RS4 owners have done likewise. Why is that? Well, price surely must factor into it.
Although the carbon-ceramic brake discs last four times longer than conventional steel discs, they cost a heck of a lot more than traditional steel discs: $15 to $20 a disc for steel compared to $665 to $2,660 a disc for carbon-ceramic. That's quite a jump. But there may be hope. By switching from batch production to a continuous process, German manufacturer SGL Carbon AG, along with Audi, are trying to change that. If they can get the process perfected, they are expecting the price per disc to drop all the way down to $465.
Some still think that's too expensive to generate real mass appeal. Perhaps they'll still primarily be seen on sports cars and exotics, but the new, lower price would make them that much more attainable to the average Joe or Josephine who wants to autocross, say, their Mazda5 on weekends. Click through for the details about the new process and the specifics about why carbon-ceramics are so superior to steel.
[Source: AutoWeek]
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Reader Comments (Page 1 of 1)
Scott 10:59AM (12/22/2006)
"the average Joe or Josephine who wants to autocross, say, their Mazda5 on weekends"
Why would one want to autocross their minivan??
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Chris W 11:21AM (12/22/2006)
They mean the older Mazda Protege 5, the wagon.
http://www.canadiandriver.com/articles/hl/images/protege5_01.jpg
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Jon 12:13PM (12/22/2006)
That would be nice if they could get it down under $500. They may not have a huge OEM push for them, but the after market would go crazy.
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MikeW 12:13PM (12/22/2006)
Why bother for the average joe when doubly vented brake rotors have a minimal cost increase.
Metal-air-metal-air-metal. Two vent channels, hence doubly vented. Thermally stable, no coning. Improved heat dissipation.
A rear axle can be 5,5,5,5,5 for 25mm thick, a front axle can be 5,7.5,5,7.5,5 30mm thick
Something like a Ford Excursion which had ~1.5" thick rotors, can have 7.5,7.5,7.5,7.5,7.5, or 5,10,7.5,10,5
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S 12:34PM (12/22/2006)
If they last four times as long, they need to be no more than 4 times the price. Get them down to 50 bucks and they'll gain popularity. This is not a performance issue, it's the economy, stupid!
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Julius 12:39PM (12/22/2006)
Forget about the racing application. Heck, just getting our MDX from the Valley to West Hollywood on a daily basis is a drain on brakes. The advantage of stoppers that will last four times as long for me is a huge one. And how much better it will be taking the TL for a weekend canyon run! Bring 'em on. I'll buy at $465.
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stevew 1:00PM (12/22/2006)
BTW, conventional brake rotors are not made of steel. They're cast iron.
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Brandon Harper 1:19PM (12/22/2006)
It's not that they just last longer, but they have a LOT less rotational mass. While this may be racing hearsay, supposedly losing 1 lb of rotational mass at the wheels is like losing 4 lbs anywhere else on the car.
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Brandon Harper 1:19PM (12/22/2006)
Off-topic, but I'm tired of approving my comments manually each time. The confimation email sends me a password, but I have no idea where to put it. Anyone?
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nagmashot 1:22PM (12/22/2006)
sorry it is plain BS to compare the price of cheap no perfromance low tech rotors build in no perfromance daily driver cars with high thech high perfromance carbon rotor prices. Conventionel high performance two pice rotors build in most high perfromance cars are not avaible for $20... $200 PLUS each rotor is more realistic! You don´t get brembo, mov´it etc rotors for $200. Standart front set rotors for a Corvette C6 are between $200-$245... if you take high perfromance rotors it costs more. The standart set of front rotors for cars like the RS6 are around $440... there the different to 4times longer leasting carbo rotors isn´t that big...
No one would put them in a 100hp Civic ...
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Frank Filipponio 2:50PM (12/22/2006)
#1 - Because we can. And it's NOT a minivan. :D
#2 - No "we" didn't. ;)
#5 - With much better performance than steel, even the $2,660 rotors are a bargain to those who have them and use them on their sportscars.
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jon benson 2:53PM (12/22/2006)
Why does a small percentage of rs4 owners take them? Because carbon brakes are wooden at best when cold.
Not everything that's on a race car works for going down the shops.
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paul johns 2:57PM (12/22/2006)
i sure have never seen a brake disk for 20 dollars some one is selling used ones to ya for that cheap
as for #5, just because they last 4 times has nuthing to do with price talke into account of changing disks 4 times
maybe the manufacturer is gettina alittle of that
stupid
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kballs 3:25PM (12/22/2006)
#12 is right... carbon discs last 4x longer... they also have 4x the stopping distance when cold (exaggerating but they do take a lot longer to stop when cold). You have to drive like a mofo to get them heated into their proper operating temperature. Standard cast iron rotors perform much better in street driving (they go to heck when raced and overheated though).
The only thing that could potentially help improve your braking performance in both street and race conditions is regenerative braking using an electric motor. There are actually concept/prototype setups being developed by parts suppliers that use wheel hub motors for propulsion AND braking (no drive shafts connecting directly to an ICE/transmission, no brake rotors) as well as having integrated electromagnetic steering and suspension... but that's getting off topic.
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Frank Filipponio 3:31PM (12/22/2006)
#9 - That feature will go into effect in March most likely. It was part of the revision to the site but will take time to set up.
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doglet 4:37PM (12/22/2006)
the real advantage is weight, weight at the rotors is about the worst place weight can be. it is unsprung weight which affects ride, it has to be spun up and spun down affecting acceleration and braking and fuel economy.
the weight advantage alone is reason enough to guarantee ceramic discs a place in the future.
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doglet 4:37PM (12/22/2006)
"Off-topic, but I'm tired of approving my comments manually each time. The confimation email sends me a password, but I have no idea where to put it. Anyone?"
same for me, anyone know wth were suposed to do with that password?
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doglet 4:43PM (12/22/2006)
"#9 - That feature will go into effect in March most likely. It was part of the revision to the site but will take time to set up."
thanks for the info frank
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nagmashot 2:44AM (12/23/2006)
reply to 12
sorry completly wrong
The Audi RS4 carbon brakes are doing 35.2m (100km/h to 0km/h) if ice cold...that is extrem high perfromance, the RS4 steel rotors are only able to do 38m (100kn/h to 0 km/h) if ice cold. The giant advantage of the carbon brakes... if they get hot they are able to do 32.4m 100km/h to 0km/h.
The reason that only 6% of the RS4 driver choose carbon brakes.... 5800Euro($7700) more expansive ...a good reason not to buy them...
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