The technical name for the disc in disc brakes, the rotor is a metal platter that’s part of the hub to which a car’s wheel attaches. It rotates with the wheel, so when the driver applies the brakes, causing the calipers to squeeze their brake pads against the rotors, the resulting friction slows the wheels’ rotation and stops the car. Rotors are durable and intended to last longer than brake pads, but they aren’t designed to last forever. When worn down, they must be replaced. If rotors become warped or pitted, sometimes they can be machined (also called “resurfaced” or “turned”), but rotor prices have come down enough that replacement is more common than it used to be.
