Loose Brakes Adjustment Guide

Brake cables (and shifter cables) on all bikes stretch with use over time and need to be periodically tightened.

The mechanical disc brakes that come with all ebikes by Rad Power Bikes are a critical safety feature and it is very important to keep them well-adjusted. The brakes are essentially the same as mechanical disc brakes that come on standard pedal bikes and their adjustment and maintenance should be very familiar to any certified, reputable bike mechanic.  

Follow the steps below to tighten the brakes on your bike, if needed. If the brakes on your bike are making noise or rubbing while riding the bike, follow the steps HERE to adjust the brakes.

Caution.png 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.

You will need:

  • A 5 mm Allen wrench
  • A torque wrench with a 5 mm Allen bit
  • The rear brake inner pad adjustment tool from Rad Power Bikes (for 2019 and earlier RadCity, RadCity Step-Thru, and RadWagon models. Contact us to order the tool, if needed)
Test the Brakes
  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. Prop the bike in a bike stand. You can also prop the bike on its kickstand, or hold a wheel in the air so it can spin without making contact with the ground.
  3. Check the brakes. Spin the wheel to check for clearance between the brake pads and brake caliper. Use the left brake lever to stop the front wheel, and then repeat with the right brake lever to stop the rear wheel.

    Brakes should be adjusted if:
    • The brake pads take longer than you would like to slow you down.
    • The brake pads make contact with the brake rotor when the brake lever is more than halfway between the neutral lever position and the handlebar.
    • The brake pads are too far away from the brake rotor.
    • One or both brake levers squeeze too close to the handlebar grip, in the photos below indicated with the X.

    Photo_Sep_06__2_27_30_PM.jpg    Photo_Sep_06__2_27_42_PM.jpg 

    Follow the steps below to adjust your brakes if needed. Once adjusted, the brake pads should grip the brake rotor when the brake lever is halfway between the neutral lever position and the handlebar grip.

    Photo_Sep_06__2_28_29_PM.jpg

Caution.png Never touch the brake rotor, especially while the wheel is in motion. Touching the brake rotor can reduce braking performance and cause squeaking; touching the brake rotor while it is moving can cause serious injury.
Adjust the Brakes

Rotate the barrel adjuster

  1. Rotate the barrel adjuster by the brake lever. Loosen the lockring and rotate the barrel adjuster in small increments so it "backs out" and moves away from the lever. Tighten the lockring to secure the barrel adjuster in place. This will increase the cable tension.

    barrel_adjuster_-_brake_lever.gif
  2. Check the brakes. Spin the wheel to check for clearance between the brake pads and brake caliper. Squeeze the brake lever to stop the wheel.
  3.  If the issue persists after backing the barrel adjuster out fully, repeat steps 1-2 on the brake caliper barrel adjuster at the wheel to increase cable tension.

    barrel_adjuster_-_brake_caliper.gif
  4. Check the brakes. Spin the wheel to check for clearance between the brake pads and brake caliper. Squeeze the brake lever to stop the wheel. If the issue persists, the cable pinch bolt by the brake caliper can be adjusted by following the next steps.

Adjust the cable pinch bolt

  1. Move all barrel adjusters to their original position. Ensure all four barrel adjusters (one on each brake lever and one on each brake caliper) are fully "backed in" and sit flush against the lockring.
  2. Add larger amounts of brake cable tension at the caliper. 
    1. Use an Allen wrench to loosen (but not remove) the cable pinch bolt just enough to allow the brake cable to slide through the bolt.

      IMG_3240__1_.jpg
    2. Pull the cable through the pinch bolt and move the caliper arm up the cable.

      IMG_3239.JPG
    3. Tighten the cable pinch bolt to secure the cable with more tension.

      IMG_3240__2_.jpg
    4. Torque to 5 Nm.

      IMG_3242.JPG
  3. Check the brakes. Spin the wheel to check for clearance between the brake pads and brake caliper. Squeeze the brake lever to stop the wheel.
  4. Make adjustments if needed. If the brake lever is too tight when squeezed, loosen the cable pinch bolt, carefully push the cable up through the pinch bolt to create more cable slack, then tighten the pinch bolt and check the brakes.

    If the brake cable has been adjusted through the cable pinch bolt fully and the issue persists, the inner pad will need to be adjusted following the steps below.

Adjust the inner brake pad

  1. Test the brakes. Spin the wheel to check for clearance between the brake pads and brake caliper. Squeeze the brake lever to stop the wheel. If the brake pad closest to the wheel hub is still too far away from the rotor, the inner pad will need to be adjusted closer to the rotor.
  2. Adjust the inner brake pad on the front wheel, if needed.
    1. At the front wheel, pass a 5 mm Allen wrench through the spokes and into the inner brake pad adjustment dial.
    2. Turn the tool clockwise 1-2 clicks to decrease the space between the inner pad and the brake rotor.

      inner_pad_adjuster.jpeg
  3. Adjust the rear inner brake pad, if needed.
    1. For bikes with a geared hub motor: 
      1. At the rear wheel, near the wheel hub, pass a 5 mm Allen wrench through the spokes and into the inner pad adjustment dial.
      2. Turn the tool clockwise 1-2 clicks to decrease the space between the inner pad and the brake rotor.

        Geared_hub.jpg
    2. For bikes with a direct drive motor (RadCity, RadCity Step-Thru, and RadWagon models through 2019):
      1. Locate the inner pad adjustment tool or a 5 mm Allen wrench. Starting in 2020, new models will ship with the inner pad adjustment tool in the assembly toolkit. To get an inner pad adjustment tool, if needed, please contact our Product Support team using the method linked HERE. The inner pad adjustment tool makes the inner brake pad adjustment much easier. If you have a 2019 or earlier RadCity, RadCity Step-Thru, or RadWagon model, don't have the tool, and want to adjust your rear brake as soon as possible, you can do so with a 5 mm Allen wrench following the instructions below.
      2. If using the inner pad adjustment tool: At the rear wheel, near the wheel hub, pass the inner pad adjustment tool in between the motor and brake caliper, and into the inner pad adjustment dial. Turn the tool 1-2 clicks, as shown below, to decrease the space between the inner pad and the brake rotor.

        Inner_pad_adjustment_tool_-_tighten.gif
      3. If using a 5 mm Allen wrench:
        1. Locate the brake caliper bolts securing the brake caliper to the frame. Use a 5 mm Allen wrench to loosen the two bolts, and remove the brake caliper.

          RadWagon_bolts.jpg
        2. Locate the inner brake pad adjustment dial and use a 5 mm Allen wrench, turning clockwise 1-2 clicks (1, below), to decrease the space between the inner pad and the brake rotor (2, below).

          Inner_brake_pad.jpg
        3. Reinstall the brake caliper. Center the rotor between the pads, reinstall the bolts, and tighten the bolts evenly. Torque the bolts to 6-8 Nm.
  4. Test the brake pad clearance and braking feel. Spin the wheel and squeeze the brake lever to check that the brake pads contact the brake rotor about halfway between the lever's neutral position and the handlebar grip, as shown below.

    Photo_Sep_06__2_28_29_PM.jpg
  5. Once the brakes have been adjusted, reinstall the battery, and test the bike fully before riding.

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