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?

  • Sounds like contamination - what do the pads look like ? How old is the bike/ how far have you gone on it? What made the brakes squeak, was it mud/grit? Is it a metal-on-metal squeak or is it a rubbing? Have you checked the rotor for runout (ie flatness) with a ruler? Do you store your bike outside?
    – Criggie
    Commented Jan 30, 2016 at 11:48
  • @Criggie It's about 4 months old only, about 600km The bike is kept in the house. Caliper is aligned with the disc and I have yet to use on a trail.
    – Mervyn Wee
    Commented Jan 30, 2016 at 13:27
  • 3
  • Consider invoking your warranty - take it back to the shop from which you bought the bike. Probably needs new pads or your rotor is contaminated. Do tell us what happens.
    – Criggie
    Commented Jan 30, 2016 at 22:01

2 Answers 2


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!


I had a very similar problem. I find the Muc-off spray by itself doesn't provide a proper solution. I solved the noise by the following:

  • Take the pads off.
  • Clean the rotors thoroughly with some Fairy Liquid and warm water, using a dish scourer sponge, making sure you rinse it totally. Dry well. Then spray with Muc-off.
  • Clean the pads using warm water and fairy liquid, use a toothbrush to scrub em well. Rinse thoroughly.
  • Dry the pads then rub the surfaces with some fine sand paper for a few seconds, wipe the dust off.
  • Spray a bit of Muc-off on the pads
  • Reassemble - hey presto, no squeek.
  • Hi, I cleaned the brakes according to your instructions. The back brake no longer squeaks but the front brake will squeak loudly upon very hard breaking. Is this normal? Or is there something wrong? Pads contamination?
    – Mervyn Wee
    Commented Feb 6, 2016 at 7:04
  • My guess is there's still something on the pads or the rotor.
    – Adam B
    Commented Feb 17, 2016 at 9:10

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