Apollo_95

Hi folks.
I recently bought my first road bike (Triban RC500). Im not new to cycling but this is my first bike with disc brakes. Ive only been on it 3 times & the brakes make a horrific squealing noise when I brake hard. I have spoken to a few different shops to see what is causing the noise. As the bike is brand new I dont think the pads will be contaminated. One place said that all disc brakes squeal when wet? Any ideas?
Thanks

Badger6

Discs will give a squeal when wet...it should abate pretty quickly depending on how much water and road grime has gotten onto the rotors and pads.

Question to you, did you bed them in? There are all sorts of theories on how to best do this...it isn't hard, but it must be done. You need to ride it and do a series of hard slow downs that put some serious heat to the pads and rotors without coming to a complete stop. until you've been through a few cycles (3, 4, 5). If you didn't do this, you may have glazed the pad surface, and or deposited pad material unevenly across the rotor surface and it will cause the brakes to be noisy.

Apollo_95

Yes I spent a good 5 mins doing the hard brakes when I first got the bike like you said. Since then Ive been out 3 times (about 40 miles all in). The noise was particularly bad last time I was out when there were alot of puddles on the ground. I genuinely
did not know that disc breaks squeal when they are wet. If I had known this I would have stuck with the rim brakes when gettinng a new bike. I know other people that have disc brake bikes & they do not have this issue when its wet so Im a bit confused to be honest.

Cpn_Dunsel

All disc brakes are loud when wet (even on autos and trucks). They only get quiet once the rotor is hot enough to burn off the water.

Watch the start of a wet CX or MTB race and one will hear lots of noisy brakes.

Badger6

If the squeal/noise doesn't abate after a few seconds of applying brake, they aren't bedded properly (glazed) or they're contaminated (oils, etc).

As for rims being superior wet? Nope. I have a nasty scar on my forehead that is testament to he stopping power of wet rim brakes when a car turned in front of me and I had to use the passenger door and window to stop. Discs are way better in every situation but dry, then it's a 50/50 proposition.

Rolla

It could also be contamination. Clean the rotors and the brake pads with some rubbing alcohol and see if that doesn’t mitigate some of the noise.

Hypno Toad

Disc brakes don't have to be loud - they should be silent. I have had four disc brake bikes (and buying a new one); I've logged well over 35,000 miles during the last 15 years ... I've learned a few things:

• First of all, never touch the rotors
• If rotors are dirty/oily, use isopropyl alcohol on a clean rag to wipe the rotors down, and use a clean dry rag to wipe them dry
• Rotors can get bent/warped, with a new bike, I'd go back to the shop that sold
• Check that the clippers are aligned, likewise, I'd go back to the shop

Lastly, wet conditions will cause disc brakes to be loud - but I'll take disc brakes for stopping in wet conditions over rim brakes ... every. single. time.
(edit: jump to 0:38 for the rollout and all the brakes squealing - start time links on YouTube links don't work here)

RiceAWay

Usually this is an easy fix. You loosen the brake calipers, Hold the brake on tight and tighten the calipers down. Do this with both wheels since whoever put your bike together got distracted or something. This will not stop them from squealing in the wet, And as the pads wear you might have to repeat this procedure. And if the disks are wearing nothing may work except replacing the disks and putting in new pads. That is very easy and simple.

Apollo_95

Thank you all for your comments. My main concern was that the guy at the bike shop was fobbing me off when he said that disc brakes squeal when they get wet. Clearly this is a real thing with disc brakes.

OuterMarker

Last winter I went on a crusade to get rid of disc squeal. I got new rotors & pads and bed them in. I cleaned the caliper pistons & made sure not to touch the discs. The only thing it did was just delay the squeal. When it's wet, all the road contaminants get all over the disc and undoes all my hard cleaning work.

Apollo_95

Im glad you told me that because this has driven me crazy over the last few days. You have just saved me alot of time & effort. Im just going to have to live with it.

tankist

SRAM documentation says they have 2 types of brake pads - organic and metal. The former are quiet, but wear faster and stop slower. The latter are loud, but wear long and stop better. You pick.

Bellman

With all due respect, I ride in wet conditions all the time and none of the disc brakes on my single and tandem bikes squeal. Also, never had a customer complain about squealing brakes on any bike I've sent out of my shop. In my opinion this is because the brakes are aligned properly. I never clean them. Always bed in new pads. Always make sure they are properly aligned. I am convinced this is why they are quiet. Good luck! PS: for me the quickest way to check alignment is visually, with a flashlight backlighting the gap between pads and rotor. You'll be able to quickly see not only if alignment is off, but also the spacing between each pad and the rotor.

Gresp15C

We've never gotten rid of the howling on my wife's new bike. Not really a squeak but like someone blowing into a trombone, and audible 1/4 mile away. I can make it happen with the bike on the stand by feathering the brakes and rotating the wheel slowly by hand. The shop was baffled, and they are a good shop.

I traced it to the resonance of the hub and the spokes, and made it go away by adding damping material around the spokes, but we don't feel it's safe to actually ride that way. It's the same after cleaning the discs with alcohol, and with both hard and organic pads. My suggestion to randomly tighten and loosen spokes so they don't all ring at the same note when plucked was taken with some skepticism, and we haven't tried it.

I think it's a coin toss how disc brakes behave from one bike and wheelset to another, and the problems are hopefully rare.

Hypno Toad

I 99% agree with you ... but check my video posted from the rollout of the 2018 Filthy 50, everyone's disc brakes are loud. And since I ride in these conditions, I do clean rotors. FWIW most people won't ride conditions like these.

Troul 

temperature & pad material is a factor in causing such noise. A pad that is resin based with least metal/ceramic material should be less noticeable.

63rickert

In other words you are a good mechanic. As a good mechanic you have learned how to do the job well.

Around here we have no big hills for simple bedding in. We also have darn few mechanics with a clue. The discs squeal like mad. The problems are endless and compounding. Bike tech works better when it is real simple. It is going to be some years before discs are simple enough. And some years before even second rate mechanics have this one figured out. In meantime am glad there are a few like you pointing the way.

Nyah

Disc brakes work great when the frame/fork has thru-axles. The problem is all the manufacturers who are choosing cheap production and sources. People want disc brakes but a lot of them get scammed by companies who are willing to sell disc bicycles/frames/forks that employ QR-skewers instead of thru-axles. My newest bicycle - one that folds - has rim brakes. The folding bicycle world seems to be dominated by companies willing and ready to make a quick buck. Rim brakes still work so, that's what I went with. I'll buy a disc fork for it later, after thru-axles become the norm.

veganbikes

Why would you have thought that? Do you frequently question people in stores? I am wondering what the bike shop employee would gain from lying to you in that situation? If they were trying to make money they could say "yeah your pads and rotor are contaminated and they need to be repalaced".

What comes next is pure comedy (probably terrible) no actual offense intended.

In a local grocery store:
Apollo: "Hi yes where can I find the creamed corn"
Grocery Store Employee "it is on Aisle 3 near the canned peaches"
Apollo: "that guy must have been fobbing me off let me find the manager...yes I would like to find the creamed corn"
Grocery Store Manager: "Yes sir, it will be found on Aisle 3 right next to the canned peaches and it is on sale this week 38¢ off"
Apollo: "what is with you guys a fob here, a fob there, everywhere a fob fob ♫old mcfobalad had a fob e-i e-i-FOB♫"

We see the grocery store employee furiously pressing the lock button at Apollo on his Ford Fiesta key fob

In Apollo's car:
Apollo's partner: "Honey did you get the creamed corn?"
Apollo: *grumble*

Back at Apollo's home on the computer:
Apollo "I want to find creamed corn at the local Shop and Stop and the employees were fobbing me off"
Internet Person One: "It is usually on aisle 3 by the peaches"
Internet Person Two: "yeah Aisle 3 but those peaches are crap don't buy 'em"
Internet Person Three: "I hate creamed corn you should go for the carrots"
Apollo: "Thanks everybody, had to check, I was worried those grocery store people were just having a right fob at me. Clearly the creamed corn is on aisle 3"

GamblerGORD53

I think the problem is often with 1 pad moving calipers. My TRP Spyre has had zero squeals, resin pads. But I only rode this tour bike in rain a few times. IME, this resin stops far BETTER. It locks on a dime, every time. My semi-metalic BB5 just screamed when wet.

Troul 

Resin by nature, will eat up quicker ime. For me, I don't mind since it'll be quieter... & I can try out something else sooner. When it comes to bicycle parts, I like to try out different brands or materials when I decide to do so.