Brake cables (and shifter cables) on all bikes stretch with use over time and need to be periodically tightened. You'll know you need to tighten your brakes when the brake pads take longer than you like to contact the brake disc and slow you down, or when one or both brake levers squeeze too close to the handlebar grip, in the photos below indicated with the X.
You want to adjust your brakes so the brake pads grip the brake disc about halfway to the handlebar grip, represented in the photo below.
The mechanical disc brakes that come with all ebikes by Rad Power Bikes are a critical safety feature and keeping them well-adjusted is very important. 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 shop.
Read through these instructions and contact Rad Power Bikes Product Support if you have questions. 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.
Notice: Never touch the brake disc, especially while the wheel is in motion. Touching the brake disc can reduce braking performance and cause squeaking; touching the brake disc while it is moving can cause serious injury.
1. Gather the tools you will need: a 5 mm Allen wrench and a torque wrench.
2. Power off the bike. Ensure the bike is in the off position and use the key to remove the battery. Once removed, press and hold the “MODE” button on the LCD display remote until the display remains off for about two seconds (it may flash on briefly). This ensures the power is fully discharged from the bike and it is safe to work on.
3. Elevate the bike in a bike stand that can handle the weight of an ebike, prop the bike on it's kickstand, or hold a wheel in the air so it can spin without making contact with the ground.
4. Spin the wheel and check for clearance between the brake pads and brake caliper. Use the corresponding brake lever to stop the wheel. Note: the left brake lever corresponds to the front brake, the right brake lever corresponds to the rear brake.
The brakes need to be tightened if the brake pads make contact with the brake disc 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 disc, or the brakes are too "loose".
Always use the correct brake lever to stop a moving wheel. Never touch the brake disc, especially while the wheel is in motion. Touching the brake disc can reduce braking performance and cause squeaking; touching the brake disc while it is moving can cause serious injury.
5. Start tightening the braked by adding brake cable tension in small increments using the barrel adjusters. There are a total of four barrel adjusters on the bike: one on each handlebar brake lever body (A, below) and another barrel adjuster on each brake caliper body (B, below). Loosen the lock ring and the rotate the barrel adjuster so it moves away from the lever or caliper, increasing the cable tension.
A. Barrel adjuster at the brake lever body
B. Barrel adjuster at the brake caliper body
6. Spin the wheel and check for clearance between the brake pads and brake caliper. Use the corresponding brake lever to stop the wheel. Note: the left brake lever corresponds to the front brake, the right brake lever corresponds to the rear brake.
Additional cable tension is needed if the brake lever feel is too loose (like if the lever touches or comes close to touching the handlebar grip when squeezed).
7. Add larger amounts of brake cable tension at the caliper. Use an Allen wrench to loosen the cable pinch bolt just enough to allow the brake cable to slide through the bolt (A, below). Pull the cable through the pinch bolt and move the caliper arm up the cable (B, below). Tighten the caliper pinch bolt to secure the cable with more tension (C, below). Torque to 5 Nm (D, below).
A. Loosen the cable pinch bolt B. Pull the cable through the bolt and move the caliper arm up
C. Tighten the cable pinch bolt D. Torque to 5 Nm
8. Spin the wheel and check for clearance between the brake pads and brake caliper. Use the corresponding brake lever to stop the wheel. If the brake pad closest to the wheel hub is still too far away from the disc, the inner pad will need to be adjusted closer to the rotor.*
- Adjust the inner pad. Rotate the spokes out of the way if necessary and slot a 5 mm Allen wrench through the wheel, directly into the hole in the center of the silver brake adjuster disc. Rotate the adjuster clockwise (to the right) to move the inside pad towards the disc about 1-3 clicks.
*Note: For the RadRover and RadMini, both front and rear brakes' inner pad adjustment will be accessible without removing the brakes from the bike. To adjust the inner pad on the rear brake of the RadCity and RadWagon, the caliper must be unbolted from the frame to adjust the pad, and then re-attached to the frame.
- Test the pad clearance and braking feel. Spin the wheel and pull the corresponding brake lever to check that the brake pads contact the brake disc about halfway between the lever's neutral position and the handlebar grip.
- Repeat as necessary.
NOTICE: If you do not have the experience, skill, and tools to complete brake adjustment and maintenance, Rad Power Bikes highly recommends having a certified, reputable bike mechanic complete these procedures as well as any future adjustments or tuning.
For questions or assistance with brake adjustment procedures or for help finding a bike shop in your area that can help, contact Rad Power Bikes Product Support by email to email@example.com or by phone to (800) 939-0310 x 2.