How to True an eBike Brake Rotor

You may have been trying to adjust your hydraulic disc brakes, but noticed that the rotor is only hitting the brake pads at a single spot on its rotation. Or maybe you were riding along and noticed a periodic scrapping or pinging noise. These are signs that your rotor may be out of true. Truing this rotor is a simple procedure, but can be tedious and require patience.

Here is a video walking through the process.

The tools you will need for this will be:

Here is the process:

  1. With the ebike in the stand, spin the wheel with the rotor you are trying to true.
  2. Listen for the spot where the rotor is hitting the brake pads, as this is the spot that you will need to true. Hold the wheel in that spot.
  3. Looking into the brake caliper, see which side the rotor is touching the brake pad. You may have to use the flashlight to illuminate the parts.
  4. Once you have identified where the rotor is rubbing and which side it is rubbing on, rotate the wheel so the part of the rotor that needs to be trued is out of the caliper.
  5. Slide the rotor into the large slot on the rotor truing tool, and very gently bend the rotor in the opposite direction from where it was touching. You do not need to bend the rotor with all of your might, just some light pulling in the appropriate direction is usually enough to get straight.
  6. Rotate the wheel past that spot to make sure the spot is trued.
  7. Repeat this process for any other spots that may need trued on the rotor.

Note: If a rotor is too warped, you may be unable to properly true the rotor, in which case a new rotor is recommended. For installing a new rotor, please see the Rotor Install section.

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