How to stop rim brakes squealing

Rim brakes are simple and reliable, but when they start squealing they are annoying and lose braking power. The usual causes are dirty rims, hardened or contaminated brake pads and pads that hit the rim completely flat.

Step by step

1. Clean the braking surface of the rims with alcohol or soapy water to remove dirt and rubber residue.
2. Check the pads: remove any embedded metal or grit, lightly sand the surface and replace them if the wear lines have disappeared or the rubber is hard.
3. Toe-in the pads: adjust them so the front edge touches the rim about 1 mm before the rear edge. This simple trick removes most squeals.
4. Centre the caliper so both pads hit the rim at the same time, and check the cable tension.

Tip: for carbon rims always use the specific pads recommended by the wheel manufacturer.