The brake disc is the part of the disc braking system, tied to the wheel, which serves to decelerate the rotary movement of the wheel itself by means of the friction created by the pair of brake pads through the pressure exerted by the brake caliper.

Together with the pads, the brake disc forms the pair of friction materials that transmit the braking force to the wheel hub and then to the rim. Due to this action, the brake disc and pad are subject to wear and must withstand very high thermal stresses. The brake disc must therefore be able to absorb and dissipate the thermal load resulting from friction.

During braking, the friction produced by the action of the brake pad on the disc creates a force directly proportional to the pressure exerted. The wheel is therefore subject to this force which opposes its rotation. The force exerted transforms kinetic energy into thermal energy, which is absorbed by the disc and released into the air in a percentage that can reach up to 90%. Due to friction, under extreme conditions, the temperature can reach up to 700°C. Added to this are other aspects such as dirt, water, salt and other elements related to the selected environment.

The discs can be fixed, floating or semi-floating, depending on the type of attachment to the wheel hub.

Fixed, where the braking track is not free to move relative to the drum or where the latter element is a single block with the braking track.

Floating, made in two pieces, where the track is free to move laterally relative to the drum thanks to specific pawls, ensuring a better resistance limit to stress, consistent braking, greater silence and fewer vibrations.

Semi-floating, hanno una possibilità molto più ridotta di muoversi.

There are four different types of brake discs, with specific characteristics for the vehicle on which they are installed.

Full brake disc
Made from a single casting and featuring a single friction ring, this solution releases heat slowly but ensures better braking force distribution.

Ventilated brake disc
Made up of two discs joined together. The internal space between the discs is crossed by a series of fins that allow for effective heat management, allowing it to dissipate while driving.

Perforated brake disc
It has the same structure as a ventilated disc, with the addition of holes made directly on the disc itself. This solution allows for more efficient heat dissipation and greater dispersion of gases generated by friction; it promotes system drying, ensuring better performance on wet surfaces; it performs a brake pad cleaning function.

Slotted brake disc
Compared to the perforated one, it has lines arranged in such a way as to make heat dissipation and cleaning of the pads even more efficient.