Bike Brakes Rubbing: Causes and Fixes

A constant "shh-shh" sound when riding, or a wheel that slows too quickly when you stop pedalling, usually means a brake is dragging. Here's how to identify the cause.

Disc brake rubbing

Misaligned calliper

The most common cause. The calliper needs to be perfectly centred over the rotor — even a fraction of a millimetre causes one pad to rub.

Fix: Loosen the two calliper mounting bolts slightly, squeeze the brake lever hard (this centres the calliper), retighten evenly while holding the lever.

Bent or warped rotor

Rotors bend from being knocked, overheating on long descents, or a crash. A slight bend causes intermittent rubbing at one point per revolution.

Fix: Minor bends can be straightened with a rotor truing tool. Severe bends require a new rotor.

Sticky pistons

Hydraulic brake pistons can stick slightly retracted, causing pads to sit closer to the rotor than they should. Push pistons back in with a flat tyre lever (with pads removed).

New pads bedding in

Brand-new disc pads often cause light rubbing until they bed into the rotor profile — usually resolves after 20–30 brake applications.

Rim brake rubbing

Calliper not centred

If one pad is closer to the rim than the other, spring tension is uneven. Most callipers have a centering screw — turn it a quarter turn at a time until both pads sit equidistant.

Wheel out of true

If rubbing is intermittent at the same point each revolution, the wheel is buckled. Read our wheel truing guide.

When to call a mechanic

• Disc brake rub returns after realignment (usually a bent rotor)
• Hydraulic pistons that won't move
• Wheel that needs truing (requires specialist tools)