If you have recently installed new brakes and they are squealing when you stop, there are a few possible reasons for this. Disc rotors can often be noisy for a variety of reasons, especially in the wet but even in the dry the dreaded squeal can still happen.
Brake Pads: The most common cause of squealing brakes is brake pads that are not properly bedded in. New brake pads need to be worn down slightly to form a proper contact surface with the rotor. If you haven’t ridden your bike enough to bed in the pads, they may squeal when you apply the brakes.
Contamination: Brake pads and rotors can become contaminated with oil, grease, or other substances, which can cause them to squeal when braking. This can happen during the installation process if the rotors or pads are not cleaned properly before installation.
Glazed Brake Pads: If you apply the brakes too hard or too frequently, the brake pads can overheat and become glazed. This causes a smooth and hard surface on the pads that don’t create as much friction when braking, leading to squealing.
Misaligned Brake Pads: If the brake pads are not properly aligned with the rotor, they may rub against the rotor unevenly, causing the noise.
Rotor Damage: If the rotors are damaged, warped or bent, they may cause the brake pads to vibrate or chatter, leading to noise.
How to fix the issue?
Try out the following steps:
Bed in your brake pads: Ride your bike for several miles, applying the brakes gently to wear down the pads and form a proper contact surface with the rotor.
Clean your brake pads and rotors: Clean your brake pads and rotors with rubbing alcohol or a dedicated brake cleaner to remove any contamination.
Check for glazing: If you suspect that your brake pads are glazed, remove them and rough up the surface with sandpaper to create a rougher texture.
Realign your brake pads: If your brake pads are misaligned, adjust them so they are evenly spaced from the rotor.
Check for rotor damage: If you suspect that your rotors are damaged, take your bike to a bike shop for a professional evaluation and potential replacement.
If none of these steps work, it’s best to take your bike to a professional bike shop for further diagnosis and repair.