Why does my disc brakes keep squeaking? I ride a Giant ATX 2. When my disc brakes started squeaking, I bought muc-off disc brake cleaner and used it on my discs and pads. It worked initially, but after 10km of paved road riding, the brakes will squeak when I brake hard. What's causing it?
Let's assume that the state of your brakes, discs, and pads is good. When braking hard, the frictions between the disc and the pads cause a lot of heat. After this heat reaches a certain level, the structure of the disc and pads material gets looser and the friction between them gets reduced, also making that awful noise. Make sure you always keep the disc and the pads clean and avoid long-time braking, even if it's not powerful. Better brake for a shorter time with more power, so your brakes will get some time to cool off before your next braking. Have fun out there!