How to Adjust Bicycle Disc Brakes

Mountain bike disc brakes use a drum and calipers to stop the bike. As the drum -- the metal cylinder which rotates with the wheel -- begins to wear down, the brakes may feel loose or sloppy. This is when you adjust the disc brakes to return the tight and crisp stopping ability. Where cantilever style brakes adjust off the brake lever on the handlebars, disc brakes are adjusted at the brake itself. There are two hex screws to use for the adjustment of your bicycle's disc brakes.

Things You'll Need

  • Allen wrenches
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Instructions

  1. Cable Actuated Brakes

    • 1

      Lean the bicycle against a rack or wall. Go to the drum side of the wheel and find two hex screws, one on the side of the brake caliper, and the other on the top of the brake. The side screw is the pad adjustment -- for the caliper itself -- and the top screw is the cable adjusting bolt.

    • 2

      Insert the Allen wrench into the side screw and turn 1/4 turn clockwise to tighten the brake action. Squeeze the brake lever to test if it is tight enough for you. If not, give another 1/4 turn twist until the setting is to your needs. If, after tightening the pad screw to its tightest you find the brakes still loose, tighten the top cable screw.

    • 3

      Insert the Allen wrench into the top hex screw -- the cable adjusting bolt. Turn in 1/4 turn increments to tighten the cable, thus tightening the caliper. Squeeze the brake lever to see if the adjustment is to your liking. Make the 1/4 turn increments until the desired brake setting is reached.

    • 4

      Turn the hex screws counter clockwise by 1/4 turn increments to loosen the brakes if too tight. Use 1/4 turn increments until the desired brake setting is reached.

    Hydraulic Brakes

    • 5

      Use the Allen wrench to loosen the two set-bolts attaching the caliper to the bicycle frame. Do not remove the bolts, loosen only.

    • 6

      Turn the two screws in opposing directions to adjust the top and bottom axis of the caliper. Turn the top screw to move the distance between caliper and drum out and the lower screw to tighten the distance.

    • 7

      Grip the brake lever and test the brake setting. Assign and assistant to adjust the screws while you hold the brake lever, controlling the hydraulic flow in the brake line.

    • 8

      Release the brake lever when the setting is to your liking. Slide an index or playing card between the caliper and drum to ensure there is no drum rub which affects bicycling performance.