Adjusting Disc Brakes

 This guide contains important information regarding bicycle assembly. It is intended to be a convenient general reference only. It is not intended to be a complete or comprehensive manual covering all aspects of bicycle assembly or safety. Please reference the Mountain Bike Product Manual for more information.

Tools needed include:

  • Socket wrench
  • 5 and 5 mm Allen wrench
  • Phillips screwdriver
  • 1/32nd inch spacer gauge

To start, rotate the wheel and look at the gap between the rim and fork. If the gap is uneven, loosen the axle nuts, or quick release, and adjust until the wheel and disk rotor are centered. Be sure to re-tighten the axle nuts or quick release afterward.

Loosen the two caliper mounting bolts and manually adjust the caliper body until the gap between the disk rotor and the inner brake pad is approximately 1/32nd of an inch.

If the brake cable is not attached to the brake arm, loosen the cable anchor bolt until you can thread the brake cable under the anchor washer. Push the lever arm forward until the outer brake pad is approximately 1/32nd of an inch from the rotor, then tighten the cable anchor bolt.

Insert the 1/32nd inch spacer gauge between the outside brake pad and the disk rotor, and while gently squeezing the brake lever, tighten the caliper mounting bolts.

Reassess the gaps between the rotor and each brake pad.  If the inner pad requires adjustment, loosen the set screw above the brake pad adjustment screw.  Turn the pad adjustment screw clockwise to move the pad closer, and counterclockwise to move the pad farther from the rotor.  Re-tighten the set screw.

If the outer pad requires adjustment, turn the barrel adjuster on the caliper counterclockwise to move the pad closer, and clockwise to move the pad farther from the rotor.

Check that the brake cable tension allows the lever to travel about 1/3 of the distance to the handlebar before the brake pads contact the disk rotor. If the lever has too much throw, move the brake pads closer to the disc rotor using the two methods described above.  If the brake lever has too little throw, this may cause the disc brake pads to rub on the rotor.  Move the pads away from the disc rotor using the two methods described above.

Refer to the Mountain Bike Product Manual for ways to double-check that the brake is correctly adjusted.