Cycling UK Forum

Disc brakes on a road bike Brilliant off road,a game changer for me many years ago.I would never entertain them on a road bike,pointless overkill,unnecessary weight,potential problems,and no,I,m not a dyed in the wool traditionalist,I just like stuff to work and ,if possible,be fixable. i.e.rim brakes.My only sensible suggestion might be to change pads to a different compound,softer perhaps?P.S. My regular ride buddy has discs and guess what,exact same issue.Could it be something to do with"sympathetic vibration" ?Possible cause,not sure what you could do about that though,apart from changing to a different make of disc thus altering ,hopefully,the dynamics of the setup.

Hi
I had this issue with an new bike and new bakes in the Alps. The noise was so loud it was embarrassing. Turned out in my case changing from sintered pads to organic cured the noise. Some say they don't last as long but I've not found that to be the case. Worth a try.

For some, a change to semi-metallic pads may also require a change of disc.

To be honest, I quite liked having brakes that squealed, especially on shared paths, where I could easily give the unaware an audible warning that I was behind them, with much less risk of being blamed for startling them.

Jim77 wrote: ↑17 Jun 2023, 7:44am Thank you everyone for your comments.

Feedback on what I have done:

I sanded the rotor and cleaned with isopropyl alcohol.

I then sanded pads and cleaned with isopropyl alcohol.

I cleaned the pistons etc with isopropyl alcohol.

However, I was not happy that that the pads looked clean enough. I therefore bit the bullet and installed some brand new semi-metallic nukeproof pads.

I then performed the bedding in braking process.

I then tested full braking and no squeal.

Time will tell if they remain so!

I have the same issue with my road bike and have done all of the above to try and resolve the issue.
I'm wondering if the OP managed to permanently fix the squeal.

Jim77 wrote: ↑13 Jun 2023, 9:35pm.... There doesn’t appear to be any leakage from the brake in terms of fluid......

commonly, rear hydraulic brakes fail to a (corrosion-induced) leak. In the very early stages, the leak is often tiny, so new pads, cleaning etc. might provide temporary relief, and the blame may be placed elsewhere. However, one of the symptoms is incessant squealing. To test for tiny/incipient leaks of this sort, apply the brake using an elastic band and leave it overnight: If all is well, there should be no leakage.

Revolution wrote: ↑4 Aug 2024, 10:52am

Jim77 wrote: ↑17 Jun 2023, 7:44am Thank you everyone for your comments.

Feedback on what I have done:

I sanded the rotor and cleaned with isopropyl alcohol.

I then sanded pads and cleaned with isopropyl alcohol.

I cleaned the pistons etc with isopropyl alcohol.

However, I was not happy that that the pads looked clean enough. I therefore bit the bullet and installed some brand new semi-metallic nukeproof pads.

I then performed the bedding in braking process.

I then tested full braking and no squeal.

Time will tell if they remain so!

I have the same issue with my road bike and have done all of the above to try and resolve the issue.
I'm wondering if the OP managed to permanently fix the squeal.

Yes did - I came to the conclusion it must have contamination and as such ultra careful not to get anything on the rotors or pads - so much so I only use water to clean my MTB now (probably overkill but I cannot bear the thought of that unearthly sound returning!)

Jim77 wrote: ↑4 Aug 2024, 9:20pm...I cannot bear the thought of that unearthly sound returning!)

I find a brake that wails like a banshee quite useful. It gets attention much better than a bell, particularly with pedestrians on bikepaths who have earphones on, or inattentive pedestrians about to cross a road in front of me.

NickJP wrote: ↑4 Aug 2024, 10:14pm

Jim77 wrote: ↑4 Aug 2024, 9:20pm...I cannot bear the thought of that unearthly sound returning!)

I find a brake that wails like a banshee quite useful. It gets attention much better than a bell, particularly with pedestrians on bikepaths who have earphones on, or inattentive pedestrians about to cross a road in front of me.

Sorry - not for me personally. But I respect your opinion.

I find the Disco Kevlar (Resin) pads to be the quietest of those I've tried (My bike, riding, brakes and rotors YMMV) they also have the nicest feel. Only downside is they wear a bit faster,, though nothing like as fast as Shimano resin pads.
https://www.discobrakes.com/?s=0&t=10&q=compounds&

Have you tried the disco copper free pads?

freeflow wrote: ↑4 Aug 2024, 11:25pm Have you tried the disco copper free pads?

I haven't, only their Sintered and Kevlar.