What indicates that a brake rotor has been "warped"?

Vibrations during braking are a key indicator that a brake rotor has been warped. When a brake rotor becomes warped, which usually occurs due to overheating or improper installation, it no longer maintains a perfectly flat surface. As the brake pads come into contact with the uneven surface of the warped rotor, the contact is inconsistent, leading to vibrations. These vibrations can be felt in the brake pedal as well as in the steering wheel, especially under hard braking conditions. This experience is a direct result of the rotor's inability to maintain even contact with the brake pads, disrupting the smooth operation needed for effective braking.

In contrast, while noisy operation may occur with various braking issues, it is not exclusively indicative of a warped rotor. Increased fuel consumption is not typically associated with brake rotor condition and would often suggest other mechanical issues. An enhancement in braking performance contradicts the effects of a warped rotor, as such a condition generally leads to decreased braking efficiency instead of improvement. Thus, the presence of vibrations during braking specifically highlights the underlying problem of a warped rotor.