Squealing disc brakes can be caused by contamination, improper setup, or pad glazing. Follow these steps to identify and resolve these issues.
1. Check for Brake Contamination
First, check if the brakes are contaminated from the brake system itself or an external source.
Remove the brake pads and examine the back. Is there any sign of mineral oil or DOT fluid on them?
- If so, your caliper or brake system may be leaking, which can contaminate the pads. Rebuild or replace the brake caliper and replace the pads entirely, as contaminated pads cannot be salvaged.
- If not, think about your bike cleaning routine. Do you use aerosol-based degreasers, silicone sprays, or other oily cleaning products? These can contaminate the pads and rotors. Replace the contaminated pads and clean the rotors thoroughly.
2. Clean the Rotors and Brake Pads
- Materials: Isopropyl alcohol (70% or higher) and a clean cloth.
Use the alcohol to clean the brake rotors and pads thoroughly. Any oils or residues from the road or from handling the components can cause squealing.
3. Align the Brake Calipers
Loosen the caliper bolts slightly, pull the brake lever to center the caliper over the rotor, and tighten the bolts while holding the brake lever. Proper alignment will ensure even contact between the pads and the rotor.
4. Check for Rotor Warping
A bent rotor can cause squealing sounds. If the rotor wobbles when the wheel spins, gently adjust it using a rotor truing tool.
5. Break in New Brake Pads
Brand-new pads need to be broken in to achieve better performance.
Take the bike to an open area. Firmly apply the brakes to slow down to a near stop, then release. Repeat this several times until the pads and rotors are properly bedded in.
Final Tips:
- Avoid Overheating: Long descents or riding while dragging the brakes can overheat them, causing squealing. Try intermittent braking on long descents.
- Choose the Right Pads: Organic pads are generally quieter but wear faster, while metallic pads last longer but may be noisier. Choose based on your riding conditions.
Happy ride!!