One of the most difficult aspects of
brake maintenance is the topic of what causes noise, and what can be done to prevent it. Every grind and squeak starts from where the
brake pad and
brake rotor contact each other. Unfortunately you cannot just spray lubricant all over the brakes like a squeaky hinge.
Every aspect of the system including the
brake rotor finish and
brake pad formula play an important part of understanding what causes noise. As
brake pads are pushed against the surface of a
rotor, the
entire brake system will vibrate, causing the air pressure to fluctuate at a frequency that is picked up by your ears as "noise". These vibrations will even change frequency with variations in torque, friction, and heat.
A
brake pad with friction material that has stable friction across temperature and environmental conditions will likely create less noise, because it will have consistent torque and will cause less vibrational excitation at the friction coupling.
Brake pads must also be properly bedded in to the
rotors they will be used with to ensure that there is a smooth and even surface to prevent
brake chattering.
Brake rotors with a rough surface finish can also create noise.