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I bought a new bike that has mechanical disc brakes. They were squeaking really hard. I tried aligning the caliper. Now the squeaking noise is gone form the front brake, but not from the back brake. I noticed that the brake in the back has less space between the disc and the brake pads, but that shouldn't be a problem. The brake pads are new and so are the discs, and I cleaned everything. What should I do?

Argenti Apparatus
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vata2323
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  • How new are the pads? Do they come from the original owner or are they yours? They may be contaminated. – Vladimir F Героям слава Jul 23 '20 at 13:32
  • Squeaking when brakes not applied and just riding along or when brakes applied? – Argenti Apparatus Jul 23 '20 at 14:09
  • What did you clean them with? My disc brakes squeak like buggery when they’re wet but it soon disappears once the pads have dried – Dan K Jul 23 '20 at 14:32
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    I've found that squeaking when the brakes are applied is common with new pads, and usually quiets down after a few rides. If they're squeaking when the brakes aren't applied, that's a different issue, and you might need to true your rotors (yes, sometimes even brand new rotors can be out of true). – MikeyC Jul 23 '20 at 17:28
  • I have solved squeaky disk stoppage by taking the rotors off and sanding them with some 800 grit paper in a random fashion. When disk brakes were introduced, I liked the concept and had a couple disk equipped bikes. I usually had squeaky brakes. disk brake pads are not mounted firmly to the caliper, but on a spring loaded pivot, so they will tend to vibrate against the rotors. You could mess around with different pad compounds, but they will probably squeak on damp rides, etc. – bradly Jul 23 '20 at 18:22
  • I have gone back to rim brakes because I like to minimize maintenance and I enjoy not hearing my bike make noise, but my wife still has disk brakes on her bike.I've made them work well enough that they don't squeal, but they still make a relatively loud sound when she applies her brakes. The squeaking is annoying, but worse than that if your brakes make a loud squeak, you are losing modulation and brake power. – bradly Jul 23 '20 at 18:23
  • @Vladimir F They are new. – vata2323 Jul 23 '20 at 20:05
  • @Argenti Apparatus They are squeaking when brakes applied. – vata2323 Jul 23 '20 at 20:06
  • I suspect they are glazed as a result of being improperly bedded in. there's a good article here: https://www.liv-cycling.com/global/campaigns/how-to-fix-squeaky-disc-brakes/20209 could that be the case? – Swifty Jul 23 '20 at 20:07
  • @Dan K I cleaned them with a degreaser spray. – vata2323 Jul 23 '20 at 20:08
  • @MikeyC I would try to wear them out a bit, maybe sand them, just like bradly said. – vata2323 Jul 23 '20 at 20:10
  • @bradly I would try to sand them. Yeah, I too think that rim brakes are easier to mantain, but I heard that disc brakes are more efficient, what do you think? Is it true? – vata2323 Jul 23 '20 at 20:15
  • @Swifty Yeah, maybe. I will try to sand them, i think this will solve the problem. – vata2323 Jul 23 '20 at 20:21
  • Does this answer your question? Avid BB5 asymmetrical pad rub position and squeal, and plenty of otehr disk break squealing questions. – mattnz Jul 23 '20 at 22:21
  • @vata2323 Most disk setups are heavier and prone to need a lot of constant maintenance, and although they stop a bike with less effort, most have crummy modulation(due to squeaking!)My personal opinion is they are just a gimmick bike companies adopted to sell more gear. I think they are annoying and frequently detracted from fun cycling. I would rather squeeze a little harder and not have to think about my bike or hear that nails-across-a-chalk board screech while I am trying to enjoy what I am doing. It's a matter of choice, some people don't mind, I do. – bradly Jul 24 '20 at 02:43
  • @mattnz Oh, so BB5 brakes aren't that good... Well maybe i would change them in the future, but for now i will try those tips from the post you send me. – vata2323 Jul 24 '20 at 06:47
  • @bradly Well the squeaking noise is pretty low on other bikes, on others it doesn't even exist, but mine squeaks really really hard, i can't even brake without my ears hurting. Thanks for sharing these informations. – vata2323 Jul 24 '20 at 06:59

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Ugh! Bicycle disc brakes are not without their weaknesses. The frequent attention and adjustment they require due to noise or pad rub is particularly irksome to me, closely followed by the system's ridiculous intolerance to pad contamination (really? That sort of flaw considering the environment they're to be used in?), the recommended "fix" being pad replacement.

Park Tool's mechanical disc brake tutorial is one of the best discussions regarding mechanical disc brake set-up, alignment and trouble shooting I've seen. The best advice I can give you is to watch the video and/or go thru the text.

A couple pointers: 1)often times when there is noise or rubbing that won't go away after resetting the caliper alignment, if you re-do the alignment loosening only one of the caliper fixing bolts, it helps to quiet the problem. 2) a disc brake rotor needs to be trued more often than people realize. Brake noise that's refractory to resetting the caliper almost always has rotor issues at it's heart. 3) the value and importance of bedding in new pads and rotors is often understated. Learn how to do it correctly. AND DO IT! 4)don't use the brake lever's barrel adjuster to tweak the pad distance in a mech. disc system.. These are only for countering cable stretch. 5) be mindful of the contamination issue and keep oils, greases and your fingers away from the pads and rotors. Keep rubbing alcohol on hand and use it to clean pads and rotors often. Use a clean rag for this.

Jeff
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