The Complete Guide to M6 Carbon Ceramic Brake System

As of March 2013, the M carbon ceramic brake system is available on all new M6 coupe, convertible, and gran coupe. Also known as the BMW C/SiC (carbon fiber reinforced silicon carbide) brake system, the M carbon ceramic brake disc is fabricated from carbon fibers.

The brake discs are manufactured by Brembo SGL Carbon Ceramic Brakes GmbH.

The M carbon ceramic brakes can be added as an option for an additional $9,250 for the new M6.

20 inch M wheels must be ordered in conjunction with M carbon ceramic brake option when purchasing a new M6 because the brake discs are larger in the front wheel and will not fit on the stock wheels provided. 

Comparison of M Carbon Ceramic Brakes to M Compound Brakes

The M compound brakes are definitely better in performance than conventional brakes however the M carbon ceramic brakes have:

  • Even more direct and spontaneous use of brake force.
  • Higher fading stability.
  • 19.4 kg (about 42 lbs) weight reduction from the rotating wheel masses.
  • Increased reliability for winter driving conditions with corrosion resistance.
  • Painted in gold.

Technical Data

Designation Unit M Compound Brake System M Carbon Ceramic Brake System
Front Brakes   6 piston, fixed caliper 6 pistons, fixed caliper
Diameter x Thickness, brake disc [mm] 400 x 36 410 x 38
Friction path / Friction ring width [mm] 76.0 88.8
Weight of brake disc [lbs] 30.6 17.1
Weight of brake caliper and pads [lbs] 15.4 16.3
Rear Brakes   1 piston, floating caliper 1 piston, floating caliper
Diameter x Thickness, brake disc [mm] 396 x 24 396 x 24
Friction path / Friction ring width [mm] 64 64
Weight of brake disc [lbs] 20.5 11.9
Weight of brake caliper and pads [lbs] 14.7 14.5

Brake Disc Design and Special Features

The M carbon ceramic brake disc is made up from 2 different materials:

  • The support body with the cooling ducts has a sintered silicon carbide ceramic base that is reinforced with high content of carbon fiber direction oriented strands.
  • The inner and outer friction coating has a much higher ceramic content.

The brake disc body will have visible cracked patterns (relaxed microstructure). This is normal for the M carbon ceramic brake disc and can remain visible during normal drive.

Brake Disc Wear Characteristics

Compared to the M compound brake disc, the M carbon ceramic brake disc has a much longer life and can last the service life of the vehicle in ideal everyday driving. Over time oxidation of the carbon fibers and sporty like driving can cause the brake disc to lose weight and strength.

Besides checking the surface for wear and damage, there are 3 additional indicators to check for wear on the M carbon ceramic brake disc:

  • 3 wear indicators (dark circular spots) per fiction surface located at every 120 degrees. 
  • Minimum brake disc weight, 7954 g (about 17.5 lbs).
  • Minimum brake disc thickness, 37.85 mm (about 1.49 inch)

Braking Performance and Effects

  • Cold Brake and Cold Tires: Depending on the braking situation, a spontaneous hard brake effect can reduce the stopping distance slightly.
  • Warm Brake and Warm Tires: When the brakes and tires are in a warm state, the braking effects will perform much higher.
  • Wet Conditions: Without a dry brake situation, a slight deceleration of higher braking effect can be felt. Also at low speed and cautious braking, an audible sound may occur with wet M carbon ceramic brakes.
  • Winter Operation: During winter time, the benefit of having M carbon ceramic brake disc compared to the M compound brake is its corrosion resistance.

Front Axle Brake Disc

The friction ring width (swept area) of the front M carbon ceramic brake disc is 88.8 mm (about 3.5 inches). This is larger than the M compound brake disc which is 76 mm (about 3.0 inches). 

The diameter of the M carbon ceramic brake disc is 401 mm (about 16.14 inches) and its thickness is 38 mm (about 1.5 inches).

Front Axle Brake Disc Hub

The brake disc hub is made of high strength aluminum alloy. Information is engraved on the hub detailing:

  • Serial  number
  • Part number
  • Direction of travel
  • Minimum weight (wear weight)
  • Minimum thickness (wear thickness)
  • Week/Year of manufacture

Front Axle Brake Caliper / Pad

The M carbon ceramic brake caliper at the contact surface of the swivel bearing is 5 mm (about 0.19 inch) less than the M compound brake caliper as the carbon ceramic brake disc has a 5 mm larger radius and friction ring.

Overall the weight of the front brake caliper including the pads is 0.4 kg (about 0.88 lb) heavier than the M compound brake caliper.

Rear Axle Brake Disc

The rear M carbon ceramic brake disc has the same diameter as the M compound brake disc however the thickness is 2 mm (about 0.78 inch) bigger.

Rear Axle Brake Disc Hub

The rear axle brake disc hub is manufactured with high strength aluminum alloy, the same as the front axle brake disc hub. Information is engraved on the hub detailing:

  • Serial  number
  • Part number
  • Direction of travel
  • Minimum weight (wear weight)
  • Minimum thickness (wear thickness)
  • Week/Year of manufacture

Rear Axle Brake Caliper / Pad

The size of the rear M carbon ceramic caliper and brake pads are the same as the M compound brakes.