These brakes come from the aerospace and aeronautic worlds, and have been adapted to serve racing purposes in the early ‘80s. Carbon-carbon material was then used to make rocket nozzles, parts of missiles as well as the brakes of commercial jet aircrafts.
Carbon-carbon is a hard material that is highly resistant to thermal expansion, temperature gradients, and thermal cycling. This is why it so well fitted for making the brakes of an F1 car.
|Carbon-carbon disc and caliper. (Photo: Brembo)|
Current F1 cars are now capable of decelerating from 300 km/h to a full-stop safely in just 4 seconds, generating a deceleration of almost 6g. The brake force - the pressure that the driver applies on the brake pedal - ranges between 40 and 160kg. Under most severe braking condition, the temperature on the carbon brake disc exceeds 1200° Celsius, making them to glow red.
Because of the complexity of the process of making carbon-carbon, very few companies produce carbon brakes. One of them is Italian Brembo, which has been involved in F1 since 1975.
Brembo supplies complete braking systems to five teams, and only the carbon material to a few other more. During the course of a full season, each team of two cars is supplied 10 sets of calipers, as well as between 140 and 240 discs, and from 280 to 480 pads.
|Serious front wheel lock up on Nico Rosberg's Mercedes. (Photo: WRi2)|
Another great advantage of carbon brakes is a very low weight. The corner weight of an iron brake system of a high performance production car weighs 20kg in comparison to just 6kg with a full carbon unit.
The disc has a maximum diameter of 278mm and its thickness varies between 22 and 28mm for a weight of 1400g.
The 6-piston calipers are made of an aluminium-lithium alloy, and are mono-block machined from forging. Each caliper weighs only 1600 to 1800g.
Producing the discs require a series of long and painstaking processes. It all begins with raw material consisting of filaments produced from precursor polymer, commonly rayon, polyacrylonitrile (PAN) or petroleum pitch.
The disc is preformed, molded with resin or by needling. Then, the filaments are heated to approximately 300° C in air. The oxidized material is then placed into a furnace having an atmosphere of a gas such as methane, and heated to approximately 2000° C, which induces graphitization and densification of the material, changing the molecular bond structure.
Finally, the disc is then machined to the proper, final shape.
|Complete brake assembly. (Photo: Brembo)|
For last season, new brakes needed to be designed to meet the challenge of the new Pirelli tires which are 2kg heavier and have softer compounds. It is now even more important to manage the car during braking to avoid the damage caused by locking up the wheels and to limit wear for tires.
To help dissipate the intense heat, the number of ventilation holes has increased dramatically. Each disc as more holes of a smaller diameter. Back in 2008, each disc only had 30 big holes. In 2012, each one had about 200 and last year, it was up to 1,000!