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nomorecatering
13th May 2013, 12:31
Are the ceramic brakes on car the same sort of carbon as the carbon brakes on aircraft...and do car brakes have the same problem of excessive wear when the brakes are cold.

Some high performance models seem to have these as standard now.

hellsbrink
13th May 2013, 16:47
As far as I understand, the biggest issue with carbon-ceramic brakes on cars is that there is a lack of "feel" when they are cold, people have ended up slamming the brakes on at low speed because they thought there was nothing happening when they pushed the pedal. Once the brakes heat up, however, that changes. This issue varies from manufacturer to manufacturer, some are better than others, but people do still think it is an issue no matter what and it ain't as if you can normally drive the normal commuter run with one foot on the brake pedal to heat the brakes up!

On a "normal" (as in "use", not whether it is an exotic or not) road car, I fail to see what the advantage is to having them as you wouldn't normally be thrashing the guts out of the thing to keep the brakes at an optimum operating temperature, and, indeed, assorted auto reviews out there cast doubt on any real advantage (Last year one magazine did a review of the BMW M6 and never experienced any "fade" from it's standard, non carbon-ceramic, brakes). Sure, they'll last longer than "regular" brakes and are lighter, but is that worth the extra cost given that manufacturers happily charge 10k for the "option"........

vulcanised
13th May 2013, 16:57
if you can normally drive the normal commuter run with one foot on the brake pedal


I'm sure that would delight the folk who moan at spending a few seconds behind a driver with foot on pedal at traffic lights.

G-CPTN
13th May 2013, 17:07
if you can normally drive the normal commuter run with one foot on the brake pedal to heat the brakes up!You could programme the 'antilock' brake system to apply the brakes automatically when the temperature was below 'working' heat.

hellsbrink
13th May 2013, 17:33
And don't regulations say that if the brakes are applied in any way then the brake lights have to come on, G-CPTN?

And what happens when that bit of the computer has a brainfart and either doesn't work or, well, works too well?

G-CPTN
13th May 2013, 18:38
regulations say that if the brakes are applied in any way then the brake lights have to come on, G-CPTN?
Most systems have a threshold pressure that is needed to actuate brakes and warnings.

It might be possible to arrange pads touching before light actuation.

radarman
13th May 2013, 20:59
To generate heat to maintain working temperature in the pads requires friction. More friction uses more fuel. More fuel means more CO2. I can hear the screams from the greenies already.

Dushan
13th May 2013, 21:14
The greenies moan at the mere mention of BMW M6...
In my "standard" BMW, 740, the brakes tend to be a bit "long" when cold. They warm up after a couple of stops an then the Teutonic "halt" kicks in, along with a head trying to go through the windsheield.

Nobody makes brakes like BMW ( ok, maybe Porsche).