uoficowboy

Hi there - I have an '07 Jamis Aurora with cantilever brakes. The last week or two the brakes have been squealing incredibly loudly. I took them apart on Friday and found that there had been some chunks of metal stuck in the pads themselves. They'd actually cut slight grooves into my rims - maybe a quarter millimeter deep or so. I tweezed out the chunks of metal but my brakes are still incredibly loud. In fact - they seem to be a good deal louder. When I brake hard - I have excellent braking force - but I'm waking the dead two counties over! I can't find any metal that is rubbing - I think it's just the pad rubbing on the rim. What would cause this?

I'm going to replace both sets of pads today as they both were fairly worn - and they have holes from where I pulled out the metal slivers.

But anybody know what would cause my pads to be so loud? The noise is truly quite incredible - I've never, ever heard brakes this loud.

Powerarranger

Learn how to toe your brake pads.

Also here.

It's a fairly straightforward procedure, and these guys can tell you a lot better than I can...

Good luck!

joejack951

Most of the squealing problems I have come across on my own bikes happened because the pad had worn such that not all of the pad material was contacting the machined surface of the rim. Especially with V-brakes and cantilevers, as the pads wear they will slowly creep down the rim towards the hub. The pad face will wear at an angle (unless you correct the pad's angle as it wears) which if let go for too long, will result in a half worn pad that's completely useless. A severely angled pad can actually be a safety hazard because you can get it set up correctly for reasonablly hard pulls on the brake lever (though a lot of the angled face won't be contacting the rim), but a full force pull will squeeze the pad off the rim causing it to become stuck (personal experience, luckily just on the bike stand). Not sure if that makes sense or not

My point is, if your pads are worn at an angle, you might need to replace them and when you do ensure that they are contacting the center of the rim. As they wear, periodically readjust them so that they wear as evenly as possible which will get you the maximum life out of the pad and avoid any squealing.

Oh, and the metal slivers are common. Removing them will help the life of your rims though.

Sixty Fiver

Strangely enough...I had to swap out the Kool Stops on a few of my bikes as no matter how I adjusted them (and I know what I am doing) they sounded like Bansidhe.

Went with my tried and tested brake pads from MEC and all is well... the stopping power is as good and perhaps even better.

I have Avid Shorty 4's on one bike and they are rather notorious for being noisome and I was almost ready to toss on a set of NOS Shimano XTR cantis if I could not get them to quiet down.

frankenmike 

IME a softer compound pad will squeal less. Counter-intuitively, the cheap 3-4 dollar generic replacement pads, though not as long lasting, are the most quiet of all the pads I've tried(which is pretty much all the major brands).

bkaapcke

Avid Pro 20's are quiet and have plenty of braking power. REI stores usually have them. If you like quiet, forget Koolstops. bk

fuzz2050

My Koolstops hardly say a word. All it takes is proper toe in. It is a little harder, with that little fin they have and all, but they give unparalleled braking. I did enjoy the period of time when my front wheel was adjusted properly, but I was to lazy to fix the rear. The front provided braking force, the rear, a warning to those in my way.

tellyho

FWIW "noisome" actually means stinky. However pedestrian it sounds, "noisy" is what you want.

fuzz2050

I have to wonder if he actually new that, and what he meant was that his avid shorty 4's were so powerful that he burnt his pads each time he braked?

uoficowboy

So one thing I should mention: they seemed to be silent indoors, but loud out. I tried getting them wet - but they remained quiet indoors. Maybe cold induced?

Anywho - I took a look and they were so worn that, even though I think they started flat, they were in a more toe out position than anything. I fixed that, and they were nice and quiet for my unseasonably warm ride home.

Thanks guys!

Doconabike

Regarding Squealing Brakes:

I agree with the above posting that setting the "toe in" is a reasonable practice when installing brake pads. About 1/2 a millimeter of toe-in seems to prevent most brakes from squealing.

I did have an interesting situation, though, in which I was using an old mavic rim and jagwire brake pads on tektro v-brakes. I set up the brakes with a little toe-in and everything was fine. In a month, though, I got horrible high-pitched squealing that wouldn't go away with re-setting the toe-in. I fiddled and fiddled and still had a very loud squeal. To make a long story short, I tried many things including changing to a new brand of brake shoes - still got a squeal.

My final salvation was sanding the braking surface of the rim with a very fine sandpaper. It seems that some fine layer of something had accumulated on the rim and was causing a squeal. After a little sanding, the system is squeal-free and stops great.

Never had this happen before and thought it was interesting.

cs1

I haven't heard anyone mention glazed pads and dirty rims. Both cheap but labor intensive fixes. A file and some sandpaper on a flat surface can clean what looks like useless pads for nothing. It's easy to fix uneven wear on pads with a file. You don't even need to remove the pads. You do need to remove the wheel.

Even properly toed pads will squeal if they're dirty.

zzyzx_xyzzy

+1

My pads squeal when they and the rim get dirty. Wash the pads and rim with soap and water and then clean off residue with ethanol. The file on the brake pads can help feshen their surface too.

cs1

That makes a much bigger difference than most people think. I'd being willing to bet that almost of half of all squealling brakes are from that.

Panthers007

I'd only add that ethanol is the type of alcohol people drink - and it's hard to find something that contains a high enough percentage to act as a good solvent. So I'd suggest using iso-propanol. Which is rubbing alcohol. Available at pharmacies, groceries, and many convenience stores. Cheap.

Oh - and the squealing comes from the harmonics created when the pad is rubbing on the rim. In a proper toe-in, it should be silent. But it's still squealing. But you can't hear it as it's out of the acoustic range of human ears. Dogs on the other hand...

You can create the same effect with a thin-walled glass - like a wine glass, by rubbing a wet finger around the top rim.

zzyzx_xyzzy

The stuff I use is sold as "Denatured alcohol" which is actually 95% grain ethanol with other stuff thrown in to make it undrinkable. In the paint section of your hardware store, even cheaper.

Panthers007

Just be careful using denatured alcohol. If that other 5% is methyl alcohol* (methanol, wood alcohol), it can/will soak through your skin and poison you in a very nasty way. Same with the vapor. It will make all your bones in your body feel like they are being twisted around backwards - like being on a chemical version of "The Rack." More can cause blindness (may be permanent). And it can kill you.

Wear rubber-gloves and eye-protection, and work in a well-ventilated area.

* A cheap & common cut.