A Brake Disc Plate (commonly called a disc brake rotor) is the rotating metal plate attached to the wheel hub of an e‑bike that the brake calipers clamp onto to stop or slow the bike. When the brake lever is activated, the brake pads squeeze against this disc, creating friction that converts the bike’s kinetic energy into heat, slowing the wheel efficiently. For e‑bikes, rotors are built stronger and with better heat‑dissipation features than regular bicycles to handle the higher weight and speed loads typical of electric bikes.