Squealing road disc brakes

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  • Squealing road disc brakes
  • On my road bike I have Shimano RS785 disc brakes. Riding in the dry and the performance is excellent and no noise from the caliper. When riding on even mildly damp roads, the brakes squeal like a scene from Deliverance. I’ve tried both compounds of pad that Shimano do and it makes no difference to noise levels. Does anyone have any ideas how to fix the issue that doesn’t involve throwing them in the bin?

    scotroutes
    Member

    Get them hot regularly. I’ve found that road bike discs are prone to contamination from traffic. Find a good hill, pedal down it as fast as possible and brake while still pedalling. I used to do this every couple of weeks when commuting in Edinburgh.

    butcher
    Member

    My hydraulic Shimanos have squealed badly from new, wet or dry. They get a lot of hard breaking too living in a very hilly area. Also very much interested in the answer.

    Unfortunately Scotroute’s technique never worked for me, I just got the impression that for certain combinations of frame/rider weight/braking style etc. you were doomed to put up with squealing brakes in the wet (e.g. gentle braking when the rotors are cold and wet, which is pretty much my entire commute, hence I went back to rim brakes…).

    I have been experimenting with extremely meticulous bedding in of new rotors and pads, apparently mixing compounds on the same rotor is a no-no (as the surface is already impregnated with the old compound) and also sloppy bedding in from new can apparently curse you to squealing as you have a microscopically uneven braking surface that sets up vibrations.

    So I very carefully bedding in one rotor at a time on the front wheel, lots of hard stops from speed but never stopping completely or locking up. Once I’d done one rotor I’d transfer it to the rear wheel and start again with the second. Brakes feel great but I’ve yet to try them in the wet.

    I notice Campag have attempted to address it on their new disc brakes, a sort of silicone-esque coating to the back of the pads to damp vibration, really interested in giving them a go.

    jonba
    Member

    If they always squeel, and aren’t giving great stopping power you may have a leaking caliper (see the long thread below).

    My CX bike squeels when just wet, but not muddy. I do remember someone saying you could help cure it by greasing the back of the pad but I’m not sure if that worked or ended up in death.

    Stopping power is excellent in wet and dry. I’ve bedded them in “properly” and it makes no difference to noise levels. Where I live there are lots of horse riders so being able to use your brakes without scaring the horse is fairly important. I’m now at the stage where I’m looking for road bike frames that will take a wide tyre and rim brakes so I don’t have to put up with the current situation. It’s either that or give SRAM disc brakes a try. I’ll never buy a road bike with Shimano disc brakes again.

    Premier Icon joebristol
    Subscriber

    I find my Shimano road disc disc brakes squeal from time to time in the wet too. Still loads of power though so not leaking callipers that I’m aware of. They’re 105 level I believe (non series).

    If it starts squealing I normally try and put in a big stop to get hem hot, then they don’t tend to squeal as much the rest of the ride.

    I’d still rather have that then rim brakes that don’t stop me at any sort of speed in the wet.

    I’m now at the stage where I’m looking for road bike frames that will take a wide tyre and rim brakes so I don’t have to put up with the current situation.

    Join the club, I’m afraid it’s an ever diminishing selection, Kinesis 4S is the best option out there I think without going touring/custom. I got a Specialized Allez on the promise of clearance for 28mm tyres but in reality it’s no better than my ‘summer’ bike with 25s on it.

    It’s either that or give SRAM disc brakes a try.

    Ug. I started with SRAM, they were ungodly with the squealing and noise (in the wet). Fine in the dry. Tried a few varieties of pad and rotor with no success, changed to TRP Spyres which were better but still pretty noisy in the wet. Now on current gen Shimano Deore with XT rotors, still not given them a run in the wet.

    I’d still rather have that then rim brakes that don’t stop me at any sort of speed in the wet.

    Decent callipers/mini-Vs with Swisstop BXP pads, it honestly never occurred to me that stopping in the wet was a big deal. They don’t feel as good as discs, granted, but it’s a fine enough margin that putting up with the squealing just seems un-necessary.

    Mister P
    Member

    Have you had mounts checked for alignment? If you are getting squeal from multiple set ups then I’d be looking at how parallel the calipers are to the rotors.

    oafishb
    Member

    There’s a good chunk of this weeks ‘CyclingTips’ podcast devoted to this very subject.
    They interview a tech guy from SwissStop.

    The answer seems to be things that have been suggested here (bedding in, heating up on descent) or a ridiculously meticulous cleaning regime post ride that no sane road biker would ever undertake.

    They think road contaminants are to blame and that this happens less to MB’s as they are not on the road as much – as mentioned above.

    As usual, they eventually sheepishly admit that disc brakes on road bikes, while giving great performance to many, come with some really really annoying traits that rim brakes just didn’t have.
    The bit about Pro Cycling team using a machine to bed in discs before a race is particularly wonderful.
    Progress eh?

    beardo74
    Member

    My spyres squealed terribly. Tried all sorts but what sorted it in the end was sintered pads. Bit less power but at least i’m Now happy using them to their full effect. Not sure what the compounds you’ve tried were??

    tpbiker
    Member

    Mine squeal like a piggy in the wet the first time I apply them but as soon as the rotor is cleared of water they are fine..until of course I apply then on the next descent.

    Defiantly put me off disks on the nice bike as the only advantage I can see of them is that they don’t shred the rims. Haven’t noticed any better stopping power.

    Mine squeal like a piggy in the wet the first time I apply them but as soon as the rotor is cleared of water they are fine..until of course I apply then on the next descent.

    Haha, I would do this too, then it occurred to me that my rim brakes work equally brilliantly once I drag them long enough to clear the rim of water, and don’t squeal like piggies while I’m doing it…

    Thanks everyone for your responses. I’ve decided that as it’s not just me, I might as well bite the bullet so I’ve ordered a new frame.

    Wow, decisive! What frame? replacing…?

    The disc braked bike is a Cervelo C3 which I will strip and move the parts over (not the brakes obviously!) to a new Kinesis 4S frame. I’ve had frames from Kinesis before and liked them, so It’s worth a gamble. My choice is limited as I need the comfort of 28mm tyres due to a variety of boring medical issues.

    sarawak
    Member

    My cable driven Shimano 105 discs squeal when wet. It stops once I’ve braked hard but returns if they get wet again.

    My Ultegra hydraulic discs have never made any noise…wet or dry.

    scotroutes
    Member

    They think road contaminants are to blame and that this happens less to MB’s as they are not on the road as much – as mentioned above.

    They really don’t pay me enough on here.

    brakes
    Member

    my Shimano disc brakes currently wail like a banshee and have no stopping power…

    Premier Icon joebristol
    Subscriber

    Brakes – probably contaminated pads from leaking callipers.

    mooman
    Member

    My discs been fine until last weekend when roads were wet/damp and theyd salted the roads a couple times previous. I have the theory that road contaminants are the culprit to screeching brakes.

    Sarawak, how are your Ultegras set up? What bike are they on?

    I think the road contaminant thing is a cop out, there’s plenty ofsquealing discs at wet CX races!

    Seems like a fundamental flaw in a braking system whose supposed benefits are superior wet weather performance that you can’t use it in the wet without contaminating the pads? I thought disc brakes were supposed to be low maintenance? 😉

    sarawak
    Member

    Sarawak, how are your Ultegras set up? What bike are they on?

    Sorry, can’t answer that. They are set up the way they came from the shop. I’ve not touched them. They are on a Cannondale Synapse carbon jobbie with Mavic Aksium wheels and centre lock rotors. That’s all I can tell you. They just work, and they are pretty damned sharp. I only need the lightest touch to get them full on.

    I don’t mind my discs squealing a little. I do a lot of riding on narrow country lanes with no footpaths so a dab on the brakes when on the 105s gives a nice warning to dog walkers, horse riders and pedestrians generally. Never had anyone bollock me for letting them know I’m coming up behind them.

    There’s no noticeable wear on the 105 rotors so I’m assuming there is no long term problem. There are greater things to worry about in life!!

    Premier Icon cheers_drive
    Subscriber

    I live somewhere very flat so only use my brakes rolling up to junctions, they therefore never get that hot so always squeel in the wet due to glazing and / or contamination. They fine if I lock them again on a rare hill.

    corroded
    Member

    With my Ultegra brakes it was using sintered pads instead of resin. Solved the problem by switching to resin, even in the wet.

    nick1962
    Member

    They think road contaminants are to blame and that this happens less to MB’s as they are not on the road as much – as mentioned above

    If so why haven’t any of my commuter bikes with disc brakes ever squealed?

    Premier Icon mcnultycop
    Subscriber

    My 105s did this, it was a leaking calliper. It didn’t leak enough to cause issues in the short term but did leak enough to contaminate everything. A new calliper sorted it.

    tjagain
    Member

    nick – its one of those things where you have to have several factors all aligning at once. contamination + resonant frequency + pad type + uneven deposits on the disc = voodoo majic. Once it starts then you get the uneven deposit of pad material on the disc even more

    I found on my commuter that they occasionally squealed in the wet and I could get rid of it by riding along holding the brake on at a point just below the point at which it squealed and then gradual increase pressure until they worked normally

    IME as well squeeling brakes are not as effective as they should be.

    butcher
    Member

    Conversely, the cable BB5s on my cross bike, which has done a few thousand miles 50/50 on and off road in all manner of grotty conditions, doesn’t squeal at all. And I can probably count on one hand the number of times it has been cleaned.

    What’s the most hassle free way of ‘cleaning’ the pads then, taking them off, dousing in IPA and igniting? Holding over a gas flame hob?

    can you retrofit threaded retaining pins to callipers that came with split pins?

    globalti
    Member

    I sold my Tricross to a colleague for commuting. He solved the squealing problem by spraying the brakes with WD40 every week, seriously. I’ve never seen such a mess.

    freeagent
    Member

    After one replacement caliper, 2 pairs of replacement pads and a pair of replacement discs I gave up with the Shimano calipers on my Arkose and fitted Hope road calipers instead.

    The only squealing I get now is a tiny chirp the first time i use them if i’ve not ridden it for a couple of weeks.

    I think the squealing noise was caused by leaking calipers – if i cleaned everything, and fitted new pads it went away for a couple of weeks, before gradually returning.

    There is an amazing amount of bullsh*t on the internet regarding this subject, ultimately if the pad+disc materials are compatible and fit for purpose, everything is fitted/aligned properly, the brakes should not squeal.

    I also think a regular spray with a proper disc brake cleaner is a good idea – i get good results with the Fibrax stuff.

    There is an amazing amount of bullsh*t on the internet regarding this subject, ultimately if the pad+disc materials are compatible and fit for purpose, everything is fitted/aligned properly, the brakes should not squeal.

    Should not, but in my experience, still do.

    Disc brakes aren’t hard to fit correctly, so the amount of bullsh*t on the internet shows me that despite people fitting everything properly, and using pads and discs which are (claimed to be) compatible and fit for purpose, brakes still do squeal.

    Perhaps manufacturers consider pads which are easily contaminated in wet road conditions to be fit for purpose, but I don’t, it shouldn’t be a requirement of running disc brakes that you go out to deliberately cook your brakes on a ride, it’s road cycling, hard stops from speed should be few and far between, especially in winter when you don’t know what sort of grip you can expect under your tyres.

    butcher
    Member

    What’s the most hassle free way of ‘cleaning’ the pads then, taking them off, dousing in IPA and igniting? Holding over a gas flame hob?

    I’ve had success by putting them in the oven for 20 minute. Get the heat up full and they should smoke nicely… Used to have leaking calipers on the MTB so I’ve done this several times, although I guess it depends on the pads themselves how well they hold up to that treatment.

    Incidentally, despite those leaking calipers, that bike has never really squealed in 10 years of riding it either. It just didn’t stop.

    Premier Icon StackEd
    Subscriber

    Had a mix of success and failure with mine. Had no problems with the older XT type calipers for a couple of years but then changed to the 805 calipers and ended up with no end of squealing and reduced (read nil) braking efficiency. Tried all sorts of fixes and taking ridiculous precautions when cleaning. Came to the conclusion that I must have the leaking caliper syndrome and now on second day of riding with Hope RX4 calipers, all well so far………..

    Thanks everyone for keeping this discussion going. Why manufacturers can’t sort this issue out is beyond me. And them it would appear. I clean my bike after every ride, including the brakes using Fenwicks disc brake cleaner so I don’t think it’s a lack of maintenance on my part.

    On a side note, the Kinesis frame I ordered was out of stock at my favoured shop so I did a bit more research over the weekend and have decided that a Ritchey Road Logic frame is what I actually “need”. I’ve found one size 49 in stock in the UK and that appears to be the only one. If anyone happens to know of a 51 in stock anywhere please let me know…

    freeagent
    Member

    There is an amazing amount of bullsh*t on the internet regarding this subject, ultimately if the pad+disc materials are compatible and fit for purpose, everything is fitted/aligned properly, the brakes should not squeal.

    Should not, but in my experience, still do.

    Yep, they certainly do.. and all the craziness regarding baking pads in the oven, blasting them with a blow-torch, running them through the dishwasher should not be necessary if the manufacturers got it right.
    Can you imagine if you bought a new car, and in order to get quiet, consistent braking you had to whip the brake pads out once a month and run them through the dishwasher?

    Regarding my previous comment about bullsh*t on the internet – i was thinking more about the hoards of armchair metallurgists who seam to know a hell of a lot about materials, and how to treat them.

    Premier Icon Daffy
    Subscriber

    Have you tried a different backing plate material? Squeal if often a combination of friction and resonance. If you change the backing material, you often change the resonance.

    I also had this (also R785s, but with 9020 calipers) and swapped from road pads to non-finned, XTR resin pads and new (Hope) rotors. It fixed the issue.

    dpfr
    Member

    I have just dumped R785s for Hope on the winter bike. Commuting 17 miles down a busy A road without front brakes was an exciting experience I do not wish to repeat. First impressions (300 km) of the Hopes are that they work very well, and silently.

    scud
    Member

    I found the Uber Components Race Matrix pads good, along with cleaning discs and pads with isopropyl alcohol after each ride, has been OK.

    I have Ultegra levers and Hope RX4 callipers on my flash bike, and they have been a revelation, so much better than any Shimano calliper i have used, i wouldn’t be changing frames, i’d be upgrading to the RX4 (4 piston too) for my brakes (weirdly cheapest place to buy them was Germany)

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