External pedal assist (PAS) sensor replacement guide

The PAS sensor can be replaced if instructed to do so by Rad Power Bikes Product Support.

The video and instructions below will show you (or your bike mechanic) how to replace the sensor on bikes with the external pedal assist system (all RadWagon models, all RadMini models, RadCity 1-4 models, RadRover 1-5 models). For instructions on how to replace the integrated pedal assist system found on other models, click HERE.


If you are not confident in your ability to successfully and safely perform all steps, we recommend having the work performed by a local, certified, and reputable bike mechanic.

Tools Needed:

  • A mini Phillips head screwdriver
  • Flat side cutters
  • A zip tie
  • A replacement PAS sensor from Rad Power Bikes
Remove the Old PAS Sensor
  1. Get the bike ready for maintenance. Turn off the bike, remove the battery, and press and hold MODE or the power button to discharge remaining power.
  2. Locate the PAS sensor near the bottom bracket and check if you can access the PAS sensor mounting bolts. If the mounting bolts are not easily accessible, click here for instructions to replace the PAS sensor on your bike.

  3. Unplug the PAS sensor connector. Trace the cable from the PAS sensor to the connector. Snip zip ties as needed to create cable slack, and pull the connector directly apart, without twisting.

  4. Use a Phillips head screwdriver to remove the two PAS sensor mounting bolts. Remove the PAS sensor and recycle it according to local rules.


    Continue to the next section to install the new PAS sensor.
Install the New PAS Sensor
  1. Locate the new PAS sensor and mounting hardware.

  2. Install the new PAS sensor, as shown in the image below. Place the PAS sensor in position so the red light rests in the mounting hole in the bracket. Thread in the two PAS sensor mounting bolts and use a Phillips head screwdriver to secure the mounting bolts. Do not overtighten.

  3. Plug in the connector. Line up the internal notch and pins and external arrows, and press directly together, without twisting, to connect.

  4. Replace any snipped zip ties and trim them to be flush and smooth. Rotate the cranks to check that they can spin freely. Check that all cables are free from moving parts.

  5. Check that there is a 3 mm space, about the thickness of two credit cards, between the magnet ring and the PAS sensor. If needed, carefully rotate the magnet ring clockwise, toward the front of the bike, while pushing it toward the PAS sensor.

  6. Reinstall the battery, test the bike fully before riding, and ride Rad!

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