Road bike disc brake squeal…

Ok, tried everything ending with new pads and discs cleaned thoroughly off the bike with disk brake cleaner.  New Pads reinserted with copper slip on the back plate.

It was good for two rides, but ever other ride since you can hear me coming a mile off, it’s embarrassing on the High St 🙂

What next? (Shimano Ultegra 8100 fwiw).

What pads? I’ve used Swiss stop RS on a variety of bikes and they’re ninja quiet.

I replaced the oem shimano pads with Discobrake semi compound.  Same noises, the compound has never been an issue on my MTB.

Noisy from new? Noisy in the wet and the dry?

I gave up on disc brakes on road and gravel for this very reason but my MTB is fine, I think you can just accumulate a lot more heavy braking on MTB brakes in a much shorter space of time, think I read a Canyon team mechanic saying it takes over 300km before pads and disc are properly bedded in. Don’t know if that was road miles or MTB Miles though.

Might just need some more miles put on them?

With any noisey Shimano brakes, my first thought is shitty leaking calipers.

Noisy in the wet and the dry

Yep.

leaking calipers

Nope, that’s all good.

They do seem to start squealing at low speed stopping though.  On that basis I’ve order some more copper grease, as the stuff I used was about 20yo.  I’ll clean & grease them again.

Currently suffering the same with the GRX brakes on my winter bike – local roads are so filthy with mud and run off from fields I’m resigned to solo riding till the world dries up as no one wants to be seen with me.

I know you said it wasn’t leaking calipers but what you describe is exactly what happens in my experience. Sometimes you can’t see the leak easily if at all.

It was good for two rides, 

Shimano Ultegra 8100

 low speed stopping though

All the shite on the roads and damp air doesn’t help at this time of year. I’ve meticulously looked after my pads and discs, following the bed in procedure exactly (SRAM) and today in the wet they started squealing and would not stop. Everyone else’s were though so I’m hoping it’s not permanent. IME having the callipers perfectly aligned with the rotors makes a massive difference as one side contacting first almost always causes squeal either when first applying or when releasing as you come to a stop.

When it’s wet, my GRX calipers with gorilla brake pads are almost deafening (hope disks)

I Just put up with it to be honest, although I do wonder if the gorilla Kevlar brake pads are to blame. I’m sure it wasn’t this noisy when I had the Shimano OEM pads in there.

The comparison my hope disc brakes with hope, discs etc are very quiet and only make some noise when they’re really wet and gritty but only for a few seconds.

Regular cleaning with IPA helps, don’t use fancy brake cleaners other than Silca Drivetrain Cleaner which causes no issues. Also, anything other than OEM pads seem to be worse. I’ve tried a few but not with new rotors each time – SRAM say if you change compounds you need to change rotors but at £90 a pair for SRAM CLX that’s a last resort…

I’ve had this on my MTB. I had exactly the same symptoms as you describe, and as previously suggested it was leaking calipers, although I couldn’t really tell, and they were replaced under warranty.

If it’s low speed, I’d check your calliper alignment.  If you’re only making contact with part of the pad during initial breaking, that’ll resonate.  I also pulse my breaks to get hard braking into the pads on several locations rather than slowly dragging.  It seems to work better when it’s wet to minimise the noise.

I can highly recommend Dura Ace, the most expensive thing ?

Tbh, it’s just the way it is, with road disc at least. Probably the extra contamination from the roads. Going out with the club on a damp day, it’s awful, all of them are squealing loudly! It really is the worst noise, and often when you’re pulling into a lovely quiet little village.

Genuinely thinking about going back to rim, for a summer bike at least.

Mine have been whisper quiet (Shimano 105) since new in June. Ridden in all conditions.

Until this weekend, on a particularly soggy ride, they just went full raging banshee volume. Very odd!

I think this is due to road contamination.  Oil/diesel get’s thrown onto the rotors and we then don’t generate enough heat to get rid of it and it just stays on the surface so you’ve got a little lubricant and a build up of friction – like running your finger around the lip of a glass.

If it’s low speed, I’d check your calliper alignment.

I’ve had a few sets through my hands that fixing tiny tiny tiny misalignment has cured honking or squealing. My new bike was out by about the thickness or the clear coat, just touched it with the tool and it’s been silent since. 14 months and a whole winter. Have had the same on MTB discs too. (the few that were incurable by alignment got new calipers (Shimano) or seals (15 year old hope) and that cured those ones… The Avids got thrown away. Obviously that cured the squeal as well!)

Tbh, it’s just the way it is, with road disc at least.

Nah, all mine, on all my bikes are quiet through all weathers, excluding the first tap of the brakes after long wet bits with no braking. Just a second or so to clear the disc/pad interface. And you get similar behaviour, but a different tone/note/sound, with rims as well!

Genuinely thinking about going back to rim, for a summer bike at least.

Yeah, i may well still be using my nice steel bike when the weathers nice and the suns out!

+1 on contamination from road.

+1 on they rarely get enough heat in them – a few times I’ve had a bigger descent or steepness, I’ve had howling brakes go silent after a few really strong braking moments.

+1 on choose really soft pad compound and definitely not sintered. I used Uberbrakes organic or Kevlar.

I had the first génération 785 calipers and it was bad, now i use XT calipers.  Still noise but one way to cure it is to brake really hard at start of the ride.

+1 on contamination from road.

+1 on they rarely get enough heat in them – a few times I’ve had a bigger descent or steepness, I’ve had howling brakes go silent after a few really strong braking moments.

+1 on choose really soft pad compound and definitely not sintered. I used Uberbrakes organic or Kevlar.

Work through the points above, but they can be a precursor to a noticeable leak

Resin pads for me. Do you use the brakes enough on-road to need semi-metallic, which can be more prone to noise?

Mine started as worse in damp conditions and a clean sorted it. It gradually occurred under dry conditions too but heavy braking sorted it. Then the brakes became noticeably poor and you could see a circle of fluid on the backing plate

Greasing the pad backing didn’t work for me, but it does a good job of obscuring leaks

Nah, all mine, on all my bikes are quiet through all weathers, excluding the first tap of the brakes after long wet bits with no braking. Just a second or so to clear the disc/pad interface.

I’m always curious (research purposes for future bikes) what brand brake/what pad etc.?

And you get similar behaviour, but a different tone/note/sound, with rims as well!

All of my rim setups are completely silent in all conditions, including the cantilevers. I think it’s down to pad choice as much as anything, Swisstop blue or Kool-stop red, all toed in with a wee piece of folded sandpaper when fitted.

I was out with two others on gravel recently, one with a lovely, brand new carbon bike with blingy Hope RX4s, howling like banshees everywhere, I was embarrassed for him and you could see it even affecting the way he rode. The other guy had some quite old looking Genesis or something with basic 105 or GRX hydraulics, completely silent for the whole ride. My only conclusion was that the older guy had just accumulated many more miles on his bike and the brakes were ‘properly’ bedded in whereas the other guys bike was just too new and there wasn’t enough pad material deposited on the rotors yet.

Genuinely thinking about going back to rim, for a summer bike at least.

I’m fully committed to rim brakes for now, winter CX, gravel, road, everything. Clearly I miss being able to slap some 50mm tyres on my gravel bike, and I don’t really enjoy rebuilding the (shared) gravel/CX wheels every 18 months, but other than that I really enjoy not having to worry about road grime, puddles, adverse atmospheric conditions, changing my braking style etc. etc. just for some peace and quiet. Problem is if you’ve gone disc I’ll bet it takes a while to get used to the poorer braking of rims, thankfully I’ve never gotten used to discs on gravel or road so I don’t miss them.

On my bikepacking bike it was leaky Shimano callipers.
On my road bike I think it’s just cheap pads from Uberbike since the basic Shimano pair they replaced were fine.
But on my road bike I don’t mind letting everyone around me know that I’m there.

I’m always curious (research purposes for future bikes) what brand brake/what pad etc.?

Right now, everything i have is either Shimano or Hope for both discs and calipers, pads are a mixture of the stock/OE hope and shimano pads and and assortment of swissstops.