UKC

Hi. Just wondering if anyone has experienced entirely non-squealing disc brakes, in this case on a road bike.

I was out today in gruesome weather and mine were howling as they usually do in the rain. 

Made me wonder if it is actually possible to have silent brakes in such conditions? 

Cheers

Just turn up the volume on your headphones 

Interesting point though.  It doesn't happen with most car brakes; wonder if its to do with the groves found on most bike brakes causing the resonance?  Or perhaps the stainless steel (which is actually pretty crappy as a brake material compared to cast iron).

Yes but no-one has ever discovered why or how to repeat the physics.

I sprayed mine with WD40 as the noise was so annoying - sorted!

If you have sintered/metal pads in there you could try replacing them with organics.

My organics still squeal, but not as bad ly. I clean rotors with meths after each ride, which seems to help... Except when I was commuting, when it's each day

Thanks all. I've tried all the usual tricks, but mine still howl like a deranged ape whenever there is rain. 

It used to annoy me until I realised it acted as a really effective warning to pedestrians, and others, that I was there!

Been watching the cyclocross world champs....brakes squealing constantly.

I guess car discs dont get so much dirt and wetness on them????

Motorcycle discs do and they're usually silent too.  Maybe it's more to do with the thickness and the mass of the disc and the pads?

It's not a magic cure (and maybe you've tried it already) but disc brake degreaser is worth a shot. Something like this, though I think the version for cars from Halfords will work just as well and is cheaper: https://www.wiggle.co.uk/muc-off-disc-brake-cleaner-400ml-aerosol?lang=en&a...

Iso propyl alchohol does a similar job. The above might just be that, I'm not sure.

I'm not so sure about using WD40/GT85 as I have accidentally sprayed my discs with that (over spray while cleaning the frame) and that has caused noise rather than curing it.

Giving your pads a light sanding to get rid of the top layer containing any crud might help. Basically, getting rid of contaminants is the key really.

I had badly squealing brakes and a combination of the above seemed to work for the rear, though it really seems pot luck. The front one turned out to be because the seal on the front caliper was leaking so getting mineral oil on the disc and caliper - the noise was horrendous! I only realised that was the issue when I had almost no braking. That was on a 105 caliper and apparently this isn't completely unheard of on these, so worth checking for that if you have Shimano brakes, before you suddenly have no brakes when you need them!

My experience was it was heavily linked to the pads and once I found pads that didn't squeak I simply stuck with them.

SwissStop apparently make some pads that do not squeal.  Can't vouch for them personally.

Wondered the same thing in the last few weeks. Then I watched the CX world championships yesterdays and got to hear what a high-end-professional squeal sounds like. Even straight out of the pits. It convinced me that squealing may be annoying but it is normal. My own experience with road discs is that it may be more associated with crap that cars/lorries leave on the tarmac. Last weekend I had a longish ride round the wet back roads of the Peak District. I started with nice clean discs/pads and had a reasonably quiet (albeit very wet) ride for a couple of hours till I got back on more busy roads closer to home. Within minutes the brakes the squealing like banshees. Coincidence? I don't know, but that's my current theory.

Car and motorbike brakes are usually fitted with copper grease between the pad and the caliper.

Probably overkill for bike brakes, but you could try it.

I'm sure i read that you shouldn;t use car brake cleaner on bikes. Can anyone confirm and remember why...

Not properly, but something along the lines of car brakes operating at a higher temperature so that the cleaner dissipates whereas at lower bicycle operating temperatures it persits acting a bit like a lubricant instead?

That's always been my technique, although I use a smear of ordinary grease. 

Never have any squeals from Hope Minis, Shimano 105s or cheap Avid cable brakes. All with sintered pads.

I thought that car disk pads had anti-squeal shims behind them.

I think, as someone else said, it is down the the thickness/mass of car pads and discs. Bike discs make a nice ping when you, um, ping them.

Certainly the aerosol brake cleaner I bought for my motorbike smells just like isoprop.  However, it might contain other stuff as well - the label doesn't say.

WD40 is basically paraffin i.e. mineral oil, and GT85 is a lubricant containing PTFE (made by the same company as WD40, incidentally).  Why anyone would even consider spraying their brake pads or discs with lubricants is beyond my comprehension.

My front brake is normally nice and quiet but the recent excessive quantities of snow, rain and crud did start it squealing.  I actually took the (sintered) pads out yesterday and gave them, the disc and the caliper including the pistons a good scrub with isoprop-soaked cotton buds.  Took it out for a run today - still cold, wet & clarty - and not a squeak.  (I had sanded the pads with wet&dry a few days previously but that clearly wasn't sufficient.)

I don't use grease or anti-seize between the pistons and the pads.  I'm even a bit chary about using mineral oil to lubricate the pistons, as is often recommended (even on this Park Tool video: youtube.com/watch?v=vQXFFgRButo&).  Basically, I like to keep lubricants away from my brakes as much as possible.

Shimano brakes do have a bit of a reputation for developing leaks in the piston seals.  I don't know whether they're worse for it than other brands but it's not helped by the fact that they don't sell replacement seal kits like e.g. Hope do (though other opinions seem to suggest that Hope need to do this because they're significantly more prone to blowing seals than Shimano; I have no opinion either way).  The most likely reason for piston seals leaking is erosion of the square profile O-ring due to dirt being pushed past it when the piston is pushed back in e.g. when fitting new pads, or bleeding the brake.  The takeaway from that is always to clean your brakes thoroughly before working on them.  (In fact, of course, that should be the mantra for all workshop tasks.)

Fully agree on the cleaning! And the park tools video linked above. I had horrific brake rub and squeal on my cross bike for a couple of months and it took me a while to realise the simple fact that they were just really, really filthy (despite me thinking I'd cleaned them.) The pistons couldn't retract enough but after following the park tools video and a couple of hours deep cleaning with cotton buds and I did go with their recommendation and use mineral oil, all good now. Basically I'd say if you think you've cleaned, clean again!

FWIW, I'd ensure the discs are clean as already suggested; beyond that, I'd be looking at a different pad compound i.e 'softer'. I'm no expert, just speaking from a motorcycling background. Hope you get things sorted.

I bought a new cyclocross bike in November for racing and winter road use. After about 6 weeks the front brake juddered. After loads of cleaning and sanding of rotors and pads that’s just about stopped but the pads are almost down to the metal after 3 months, so that’s £20 (I ignored the advice that I should buy new rotors too) You can’t even touch the rotors or get soap on them in case they get contaminated. Massive pain in the arse, and complete overkill it seems to me for cx because the second you stop pedalling you come to a standstill. Whole thing has pissed me right off. 

I went from sintered to resin pads and that seems to have made a difference to the squealing of mine. My initial pads (resin) only lasted 3 months, then the next lot (sintered) had been going for around 3 months until I went back to resin pads. Hoping for these current ones to last longer with winter road rather  than off road use and more cleaning.

I am pretty sure the main reason bike brakes squeal but motorbike and car brakes don't is down to disk size: Larger disks on powered bikes/ cars have a lot more mass so vibrate at less annoying frequency. Also the huge rotors on a mates downhill bike used to be much less 'earwax melting' than my XC bike.

Also I think some older single sided designs flex the rotor that also adds to the vibration.

Commercial disk and clutch cleaning preparations are a mixed bag, some are pretty much isopropyl alcohol in a can but others contain a cocktail of organic solvents. The one I have sat in the garage smells like it has a goodly quantity of xylene in it. I would assume most brake pad materials would survive it but have always been too chicken to test it so I degrease my rotors being careful not to get the stuff on the pads.