When rotors are scored or causing a pulsing pedal, you have two options: resurface (turn) the existing rotors, or replace them with new ones. Both restore smooth braking - but which makes sense has shifted over the years. Here is how to decide.
What resurfacing does
Resurfacing puts the rotor on a lathe and machines a thin layer off both faces to make them flat, smooth, and parallel again. It can cure a pulsing pedal from uneven thickness and clean up light scoring - but it makes the rotor thinner, moving it closer to its minimum thickness. See rotor minimum thickness.
When resurfacing makes sense
- The rotor has enough material to stay safely above minimum thickness after cutting.
- The damage is light scoring or mild thickness variation, not cracks or deep grooves.
- You have access to a quality lathe that leaves a proper finish.
Why replacement is often the practical choice
Many modern rotors are made relatively thin to save weight, leaving little material to safely machine away. Combined with the affordability of new rotors and the labor cost of turning, replacement is frequently the more sensible option today. New rotors also come with a fresh, correct surface for bedding in new pads. A rotor that is cracked, below minimum, or heavily grooved must be replaced, not resurfaced.
Either way, do it in pairs
Whether you resurface or replace, do both rotors on an axle so braking stays even - see do you need to replace both rotors. Fit fresh pads and hardware, and bed the new pads in - see the bedding guide. Brakes are safety-critical - if unsure, have a professional measure and advise.