Why Bike Brakes Squeal

Noisy brakes may need to be "toed-in", changed or cleaned.

Squealing brakes is a common problem that bicyclists encounter. Bicycle brakes that squeal are usually in good condition and can be easily fixed. Noisy brakes may need to be "toed-in," changed or cleaned.

Causes

The brake pad on a bike is the rubber piece on the brake that strikes the rim. A squealing noise can be the result of the vibration of the pads against the rim. If the pads are not contacting the rim at the proper angle, the brakes must be "toed-in." There might also be debris build up on the rims or the pads may be too old.

"Toed-in"

"Toed-in" refers to a slight angling of the front edge of the brake pad. This angling enables the front edge of the pads to touch the rim before the back edge. When the front edge hits the rim, there should be about a .5 mm space at the rear of the pad. The proper angle can be set using a piece of cardboard under the back of the pad.

Other Remedies

Brake pads wear down each time the brakes are applied on a bicycle. If the brake pads are too old, they must be replaced. For brakes to function properly, rims and pads must be clean. There may be residue build up on the rims that can be cleaned with an oil-free solvent, such as rubbing alcohol or citrus. Simply scrub the rims and wipe the surfaces of the brake pads.

References

• Sheldon Brown: Direct-Pull Cantilever Brakes
• Jim Langley: Keep it Quiet - Finding and Silencing Clicks, Squeaks, Clunks, Rattles and Other Annoying Noises
• Bike Man: Rim Brake Squeal / Adjustment
• Jim Langley: Fix those stoppers