Brake discs, or rotors, are metallic circular components integral to a vehicle’s braking system, mounted on the wheel hubs. They function as a friction surface for brake pads, converting kinetic energy into thermal energy via clamping force to decelerate or stop wheel rotation. Discs are typically constructed from gray cast iron, though carbon ceramic and composite materials are also utilized for performance applications. Key characteristics include diameter, thickness, venting style (solid, vented, drilled/slotted), and rotor hat offset. Variation exists between solid, vented, and cross-drilled/slotted designs, impacting heat dissipation and performance characteristics.