Hi everyone my name is Marc, and you’re here because you have had enough of one of the most annoying sounds shy of nails on a chalk board “Disc Brake Squeal” ! Well I feel the same way you do and I want to help all my fellow riders by getting the Squeal Out of your bicycles.
Squeal, Hum, Vibration, Chatter, etc can be caused by many things, here are a few. Squeal is often caused by glazing, that’s when sand dust gets baked into your pads and rotor and forms a thin layer of glass. Some of us question whether or not bicycle rotors can get hot enough for this to occur like it does on cars and ATV’s.
Contaminants are another cause. You never know what’s in a stream you crossed or water you may have ridden through.
Salted winter roads are a major cause of disc brake squeal. Pads that are heavy with metallic can cause it; pads that are too hard of a compound are sometimes a cause. This list can go on and on so I won’t bore you with all the theories.
I think we can all agree that when disk brakes do squeal, vibrate or hum that it is very unpleasant. Yes sometimes there will be a mechanical problem like pad misalignment, or maybe a return spring gets sucked between the pad and rotor.
In some cases one pad moves before the other and pushes the rotor into the caliper or into the caliper adapter bracket causing a metal to metal contact. Again there can be many mechanical causes that have nothing to do with contaminants or glazing.
However, a lot of the time it is a poor relation between the pad and rotor that causes the problem. Sometimes, brand new brakes will do it right off the bat. It’s not fun when you are a bike mechanic that just installed a brand new expensive set of disc brakes on a customer’s bike and it hums and squeals upon a test ride.
Next thing you know you’re installing new pads and it doesn’t help so you try a different rotor still no change then what. A call to the manufacturer for more pads to try, still maybe no relief.
I have been in this position many, many times so I share your frustration.