What does the presence of grooves on a brake rotor typically indicate?

When grooves are present on a brake rotor, it usually indicates excessive wear. As the brake pads press against the rotor surface, friction occurs, which can lead to the formation of grooves over time. These grooves become more pronounced as the rotor is subjected to continuous use, particularly if the brake pads are worn down and not making even contact with the rotor.

Excessive wear can negatively impact braking performance, as it can lead to reduced surface area for the pads to grip, longer stopping distances, and potentially, brake noise. It is important for technicians to inspect grooved rotors because they may need to be resurfaced or replaced to ensure that the braking system functions safely and effectively. Proper maintenance involves monitoring the condition of brake rotors and replacing them before grooves lead to severe problems.