How to adjust the disc brake pads of a bicycle

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  • OVERALL DIFFICULTY INDEX: 2/10
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BEFORE YOU START
  • You mainly need a set of Allen keys to carry out this job.
  • It remains a simple intervention provided you proceed with method and patience.
  • This is shown on a mountain bike (MTB) but the same applies to any other type of bicycle fitted with disc brakes.
DISCLAIMER:
Our pictorials are of informative nature and do illustrate works carried out by ourselves at our own premises for our own use and satisfaction.
Readers who envisage to carry out similar works inspired by the below method shall do this at their own risks and liability.

Understanding how bicycle disc brakes work

Unlike bicycle cantilever brakes that push rubber pads on to the wheel trim, this brake system is similar to the one found in cars.
A perforated disc rotates along with the wheel and is slowed down by the friction of two pads.
​The mechanism is operated by the brake cable.
The bicycle brake caliper is shown here. Note well:
  • The two bolts that fix it to the wheel fork and allow its tilting adjustment.
  • The pad to the cable lever side (left) which moves with and can be adjusted with the cable length.
  • The pad to the opposite side (right in this case) which is fixed and can be adjusted with an Allen key.

Step 1: Tilt the brake caliper until pads are parallel to the disc.

If your brake pads are touching the disc on part of a complete wheel turn, you might need to tilt the whole bicycle brake caliper until pads are parallel to the disc.
Loosen the adjustment bolts as shown below and tilt the caliper with your hand then tighten the bolts again.

Step 2: Adjusting the disc and wheel

Having checked first the caliper tilting as explained above, and in case the disc still touches a pad on part of the wheel turn, proceed as follows:
  1. Rotate the wheel slowly and check if it is not simply badly fitted on its seat in the bicycle fork. Check if the wheel is parallel to the bicycle frame. If needed, slacken the wheel fixing nuts, move the wheel in its seats until equidistant from the bicycle frame, then tighten the nuts again.
  2. Make sure to rotate the wheel with your hand slowly while looking at the brake pads for checking when exactly the disc touches the pad. Rotate the wheel so you can put your thumb on that particular point of the brake disc and apply a strong pressure for bending the disc and correcting the fault. 

Step 3: Adjusting the bicycle brake pads gap

Adjust first the fixed non moving brake pad with an Allen key. Bring it to a gap of less than 2mm with the brake disc.
Loosen the bolt that holds the brake caliper cable and pull the cable with your hand until the moving pad is at the same distance from the brake disc, then tighten the cable bolt.
Try your bicycle brakes several times before riding it.

See also...

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