Carbon Ceramic Material (CCM) brake discs were first introduced to the Ferrari line up on the Enzo in 2002. They later followed on the track focused Challenge Stradale and became standard equipment on all current models in 2008. Maserati introduced CCM brakes with the GranTourismo MC Stradale in 2011.
The benefits of CCM brakes are largely twofold – they can cope with much higher temperatures than their metal counterpart and are significantly lighter, reducing unsprung weight. There is an excellent video on the manufacture of CCM brake discs here.
The most significant downside to these brakes is the cost – as with any relatively new and uncommon product the manufacturing cost is high. Replacement brake discs are typically £2,500 – £3,000 per disc. Interestingly Ferrari only offer a 10% margin to their authorised dealers on any CCM product.
Another issue is that measuring the wear of these discs is problematic. A steel disc loses material evenly from both faces of the disc so determining if the disc is worn is a simple matter of measuring the thickness and comparing it to the manufacturers stated minimum. CCM discs do carry a minimum thickness – 33.5mm in the case below:
However, this doesn’t mean anything. The thickness of the disc was 34mm despite being beyond its usable life.
This is because CCM brake discs wear in a much different way. The wear manifests itself as chunks of material falling out of the surface of the disc. The overall thickness remains unchanged but the disc has lost material from the face, thus braking surface is reduced.
The instrument cluster of the car carries an estimation of brake disc wear based on the number and intensity of brake applications. The car whose brakes are pictured (a California) was showing brake wear of 12% at the front and 10% at the rear. Now I should point out that although the wear rate is an estimation it isn’t that far off that it would suggest such low wear rates for discs beyond their useable life. In this case I suspect that the wear rate had been unscrupulously reset as some point during the past.
This is what greeted me when the car rolled into the workshop and prompted the investigation:
New CCM discs have a very smooth, almost polished mirror surface. A far cry from these…
The correct way to determine the wear is to weigh the discs (and bells) and compare this to the stated minimum weight. In this case all four discs were below the minimum, the rears much more than the fronts. I suspect that this car had been used extensively on track with the stability control on – it brakes the rear wheels to keep the car on track which could explain the extensive rear wear.
If you own a car with CCM discs then it is probably worth having them weighed whilst the car is being serviced – it’s the only way of knowing for sure…
Related posts:
- Ferrari 360 & F430 Brake Pads
- Ferrari 360 & F430 Front Brake Pad and Disc change
- Ferrari 360 & F430 Handbrake Pads
- Rear Discs and Pads Change
- Stainless Steel Brake Hoses
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Aldous Voice 