Discover How Brembo Produces Carbon Brake Discs and Pads for Formula 1, IMSA, and WEC.
It all starts with round, fuzzy sheets of fabric. At first, these carbon-fiber sheets look more like something from a fashion atelier than a crucial component of a race car.
Inside Brembo’s Racing department, these sheets will be transformed into carbon brake discs and pads destined for Formula 1, IMSA, and WEC. These ‘hairy donuts’ eventually become those glowing red rings behind the wheels of the fastest cars on Earth. Here’s how.
The first stop for the carbon weaves that Brembo sources from the world’s best suppliers is the needling machine (Needler). Each brake disc is made up of dozens and dozens of layers of carbon fiber, with the number varying according to the disc’s thickness. To the touch, it feels very similar to a piece of fabric.
The Needler is a mechanical press equipped with an extremely high number of needles. As the disc rotates, the needles stitch together each of the roughly 40 layers of carbon fiber. This puncturing process firmly binds the fabric layers, making the fibrous ring incredibly dense. Once the needling process is complete, the disc has gained thickness, feels soft to the touch, but still looks more like a polishing pad than something capable of stopping a car.
Carbon brake pads, on the other hand, are built differently and do not go through the Needler. Instead of being pressed to achieve maximum density, the carbon sheets are stacked like a pile of paper sheets. ‘For the pads, we want them to have much lower thermal conductivity compared to the disc,’ explains Andrea Algeri, Brembo Racing Car Market Manager.
‘We want all the heat to be absorbed by the disc, because it rotates as the car moves and can cool down quickly. If the pad were to absorb all that heat, it would raise the temperature of the caliper and its fluid. Part of the design of the carbon pad is to prevent heat from transferring from the disc into the caliper.’
After the needling process, the discs enter a furnace where temperatures can reach up to 2,700°F (about 1,482°C). Carbon-rich gases permeate the carbon-fiber preforms and react with their internal structure, depositing carbon within the weave in a process known as Chemical Vapor Infiltration (CVI).
This is why these racing brakes are often called carbon-carbon brakes—not because both the disc and pad are made of carbon, but because, as the carbon-containing gas decomposes, it deposits atoms inside the disc.
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Slowing down race cars from speeds of up to 217 mph (about 350 km/h) generates a tremendous amount of heat, causing the discs to reach temperatures close to 1,000°C. This is why the ventilation holes in carbon brake discs are so important and indispensable. This brings us to the next step: drilling.
After the furnace has baked the stacks of carbon fabric into a dense ring, it’s time to finish and remove material.
An extremely complex machine is used to refine the discs by turning their surface and drilling the internal thickness using special ultrasonic drills. LMDh car discs receive 432 holes, while Formula 1 brakes get over 1,000. To give you an idea of how much carbon brake disc ventilation has evolved, consider that in 2002, when Michael Schumacher drove a Ferrari to his fifth Drivers’ World Championship, Brembo’s F1 carbon discs had only 72 holes to dissipate heat.
Brembo brake discs face radically different durability and performance challenges between Formula 1 and endurance racing, reflecting two opposing philosophies of thermal stress. In Formula 1, the absolute priority is peak performance and lightness, with the goal of making the carbon disc last for a single race distance (at least one race weekend). The discs are designed to withstand extreme and rapid thermal cycles (short but extremely intense braking), prioritizing the highest possible deceleration power over a limited time frame.
Conversely, in endurance races (such as the 24 Hours of Le Mans), the required lifespan is thousands of kilometers, and the challenge shifts to thermal consistency and long-term structural reliability. The disc must maintain its integrity and an extremely predictable wear rate throughout the entire stint, ensuring that power and feel remain stable across thousands of cycles and wide variations in ambient temperature (day/night).
LMDh series discs also feature three wear indicators—the first measures about 1 mm deep, the second 2 mm, and the third, even smaller, 3 mm—to provide teams with a quick indication of how much material remains.
Although each team has access to highly precise sensors that monitor everything about the brake discs during the race—from temperature to wear status—these visual indicators remain a valid and effective backup tool in case of doubts or telemetry anomalies.
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How much does a carbon brake disc wear during a 24-hour race? Typically no more than 4–5 millimeters, and it’s quite unusual for them to wear beyond the second notch during the 24 Hours of Le Mans. In fact, discs used in endurance races are not thrown away; teams often reuse them during tests or qualifying sessions for subsequent races, both for budget reasons and to help drivers get accustomed to the feeling they might experience toward the end of a long race with partially worn friction material.
After drilling, a robot sprays a special anti-oxidation coating on the non-friction surfaces of the disc to prevent it from losing density before reaching a team. Throughout the entire production cycle, brake components are weighed to identify any errors or inaccuracies.
At the end of the production process, Brembo’s Quality Control engineers inspect every single brake disc. Using 3D optical scans, contamination tests, and other tools, Brembo ensures that every brake component it produces is perfectly aligned with the specifications required by customer teams and regulations. Each disc carries a serial number that traces its entire life—from the raw material used to its application in a specific race.
Once packaged, the brakes are shipped by air to teams worldwide. Brembo brakes have won Le Mans 31 times with eight different manufacturers. Their discs last well beyond the mileage a Le Mans car will cover during the 24 hours. In laboratory tests, they have withstood a number of braking cycles equivalent to 3,728 miles (about 6,000 km), enduring the thermal stresses generated during braking.
The entire process of layering, needling, carbonization, machining, coating, and inspection takes about four months. Brembo produces only around 3,000 discs per year, with about 800 reserved for LMDh prototypes.