by: S.F. Heron
Posted on: Sunday, January 6th, 2008 at 11:41 pm by: S.F. Heron
Do you hear a high-pitched squealing or squeaking noise every time you apply your brakes? This irritating sound is a sign that your brakes need maintenance and proper adjustment. Vibrations generate sounds as the brake pad touches the bike wheel with uneven pressure. Friction warps the brake pad and can damage the rim every time you depress the brake lever.
Brake pad material is soft, to prevent damage as it rubs against a moving bike wheel. With every brake application, grains of dirt and debris are ground between your brake pads and bike wheel. The rim gets heated up, sometimes causing a glaze to form on the surface of the brake pads. All of this is a recipe for a noisy brake.
Make sure your bike wheel is completely round (true) before attempting to adjust your brake pads. These instructions are for maintaining conventional brakes, not disc brakes. Safety is paramount, so if you’re uncomfortable working on your bike, take it to a shop for maintenance.
Servicing your brakes requires rubbing alcohol, fine grit sandpaper, and some patience. Allow time for re-adjusting if necessary. The object is to eliminate that squeak and service your brakes for improved safety.
- Disconnect your brakes. Using rubbing alcohol and a clean cloth, thoroughly wipe both front and rear bike rims on both sides of the bike wheel. Completely remove the buildup of dirt and debris.
- Clean the brake pads with alcohol. Check each pad to make sure deterioration hasn’t exceeded the wear indicator. If it has or if your brake pads are several years old, get replacements.
- Examine the pads for ridges, ragged edges, or glazing. Trim loose ends with a sharp knife, being careful not to damage the pads. Lightly sand the pads to smooth them.
- Reconnect the brake pads and go for a test ride. Has the sound disappeared or lessened? If you still hear some squeaking, it’s possible your brake pad alignment is incorrect.
Bike maintenance shops differ in their opinion of setting your brake blocks. Other folks firmly believe that brake pads must lie completely flat against the bike wheel. The object of this brake adjustment is to slant one end of the brake pad closer to the rim to eliminate vibration.
- Loosen the brake pad holder. Slightly angle the leading edge of the brake pad closer to the rim facing in the direction the wheel travels. You are increasing the gap between the rim and brake pad at the back of the pad when the front edges strike the rim. The measurement for this space should be .5mm, or roughly the width of the piece of cardboard.
- The pad should not rub or slip under the rim. Retighten the brake pad holder.
- Take another ride. If you’re still squeaking, it’s possible the angle of toe-in needs to be increased a small amount. Readjust and perform another test drive.