Bogaurd

Hi,
I've got discs on my bike, and ever scince i've had them, they've had an annoying tendancy to squeak.

The pads are well and worn in, with over 300km of riding done. Neither the discs or pads are dirty or contaminated. The squeaking seems to occur mostly when i feather the brakes. I'ts not particularly loud, but it's very irritating. It's like the sound a car with squeaky brakes makes - very high pitched.

Yesterday i went down to my local auto garage, and asked if they had any copper grease - to put on the back of the pads. The guy was kind enough to give me half a bottle of 'disc brake quiet' - quite nice of him really.

Anyway, i put it on the back of my pads, and the squeaky noise seemed to be gone... untill i took my bike for about 30km of riding today. =\

It still makes the squeaking! Does anyone have any other suggestions as to what i might try?

Thanks alot.

Bianchiriderlon

Try greasing the pads. Only kidding! I have no experience with disk brakes, but squeaking regular brakes can often be quieted with a toe-in adjustment. Is there a similar adjustment on your disk brakes?

Bogaurd

No sadly....
I've heard of other having the same problems, but havent found a definitive solution. They still *work* fine, but it's annoying when i'm riding down a hill and trying to keep a slow pace to go with a pedestrian or summin.... it's either a constant squeak or really jerky braking.

It's not the same kinda squeak that you get from rim brakes... it's really ultra high pitched.

=/

FarHorizon

Are your rotors true? If the squeaking is cyclic, this may be a cause. You'd also want to make sure that your return spring tension is set high and that your pads aren't dragging. Other than that, new pads are CHEAP. Put on a fresh set & see what you get.

VerticalDrop

My front disc was squeeling under light brake pressure... I put a small dap of caliper grease on the back of the pads which helped quite a bit. I later checked the mounting bolts for the caliper and found my front allen screws were snug but not tight. Tightening them down vanquished the squeal, and it has not returned!

As obvious as it was, I hadn't checked them beforehand... I just assumed they were tight since I just bought the bike, and it was just "tuned" at the LBS. Now I'd like to get the caliper grease out of my brakes and see if I'm still squeak free (most likely will be).

Good luck- silent discs are a beautiful thing

-Scott

NuclearParanoid

Mine stopped. Or I just got used to it Usually my discs start to squeal after long braking, maybe because the rotor gets hot. So what I do, I alternate brakes, if the front one starts to squeal I brake with the back one.

G4teamG

Denatured alcohol. You can buy it at the Home Depot. Use a clean shop towel (not a paper towel). Don't use any grease, it will only attract dirt and build-up. I've had the same problem. Now when I wash the bike I just make it part of the routine. I do this approximately every 3 rides. Good luck.

Raiyn

Bad move. You didn't state what kind of discs you have, but putting automotive disc brake products on a bicycle system is inadvisable.
If you had searched you would have found several discussions on the matter. It's not a unique problem at all.

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The only thing

Products such as Copaslip or copper grease are also inadvisable do to contamination risks. Bicycle rotors don't generate enough heat to burn off these materials.
A heavily applied bike disc can excede 450 deg F. Trail riders doing anything more than cruising can reach 350+ without any trouble.
However, family car's brakes can hit up to about 600 degrees CELSIUS which is 1,112 degrees farenheit. Sports cars get even hotter so please no car products on bike parts.

Raiyn

Preach it brother

Bogaurd

Okay.
Just checked my rotors, they're true. I checked all the allen bolts, nice and tight.
On my way down to the hardware store now to see if they have some 'denatured alcohol'...

Bogaurd

Thanks for all the input so far everyone.

I just got some 100% pure denatured alcohol from the hardware store, and cleaned my rotors with it. Unfortunatley, this didn't fix my problem.

I was looking at my brake assembly when I figured what the problem was.
These are my calipers (mechanical):


If you try to imagine how it works, the cable is pulled, and the round bit turns, and in doing so pushes the caliper againt the pad. The problem is, the caliper turns as it rubs on the back of the brake pad.

The 'disc brake quiet' that i had goes on liquid, but dries a soft, gummy solid. As the caliper pushed and turned against the back of the pads, it rubbed the 'disc brake quiet' off. You can see the rub marks in these photos of my pads:


I figure that i need to put something between the pad and the caliper to insulate the sound, but something that will stay liquid - like some kind of grease. This would explain why the 'disc brake quiet' worked for a little while, but then became useless.

Any suggestions?

Bogaurd

Finally, after too long of messing around with this, I've fixed it.

I'm sure that any other self-confessing computer geeks will know what this is:


It's called 'Artic Silver', and is basically used to ensure good thermal conductivity between computer chips and their heatsinks.

After trying the 'disc break quiet', trying cleaning the rotors with denatured alcohol & trying copper grease behind the pads, all with no luck, I came up with the idea of trying this stuff.

Because it's whole purpose is to fill tiny air gaps and ensure good heat transfer, I figured it would be excellend at damping noise from my disc brakes. And of course, as a heat transfer agent, it can naturally withstand high temperatures. It is also at home under high pressure, as computer heatsinks are often coupled to their chips with very tight clamps.

I got my little tube of artic silver out, and after wiping the backs of pads and calipers clean, applied some to each. It's a very thick paste, and sticks to fingers alot, so to apply it well, you can put some cling-wrap over your finger and rub it on with that.

I've been trying my hardest to make my brakes squeal now, but with no luck!

If anyone else has the incurable problem of squeaky disc brakes, I'd really reccomend trying this. You can get yourself a tube of Artic Silver from any *real* PC store, but not from a department store that simply sells computers. Failing that, you can pick it up online. (Search google or try eBay)

Make sure you don't get the adhesive compound though, otherwise your brake pads will be stuck to your calipers!

Brian

It's a good thing that stuff works. Moose piss is hard to find in Oz.

Bogaurd

That it is.

Raiyn

Disc brakes squeal when they are improperly set up. Band aid fixes like this do not address the real issue. I've set up many many sets of discs over the last few years andwhen they are installed correctly (following the instructions given) they typically DON'T SQUEAK. You have now introduced a contaminate into the system which can potentially cause damage to your calipers and or get onto your rotors which in turn will contaminate your pads.
A better solution to the problem would have been to purchase a set of EBC pads (green or red) and tossing those crappy resin pads in the garbage

lcjohnny

Please no one use copper grease on bicycle discs!

Brake squeal is caused by high frequency vibration of the pad when applied. A little grease may damp that down but the risk is that when heated normal grease will exude oil (it is designed to do that) and lubricarte the disc itself - a bad idea!


Copper greases are not anti-squeal greases. Copaslip and the other copper greases are anti-seize products for where heat will dry away normal grease. E.G. exhaust bolts. The only use of Copaslip on motor-vehicle disk brakes is traces on sliding metal parts as the intense heat will dry out ordinary grease. Bicycle discs are never ever working that hard so I really would not advise it!


Anti-squeal compound (also called "rubber grease") is a stiff and rubbery grease you apply to the rear of the brake pad where it contacts the operating piston. Usually it damps out the vibration enough to get rid of audible squeal. But some brakes do just squeak and it is hard to control

IMHO there is absolutely no reason not to use proper genuine anti-squeal compound on bicycle disc components. You can get it from most good bike or car parts shops in very expensive 500ml tubs or little sachets at about 60pence in UK


Jon

digger

I have the same problem with squeaky brakes. I have Tektro IO discs and when they get wet they squeak, I thought discs weren't supposed to do that when wet?

Anyhow, I asked my LBS if it was possible to get a differant type of pad for these Tektros. They said no, only one type is available and that's what came with the bike. I also find these pads wear fast too - 300km is about all I get. By no means am I a serious MTBer, just bouncing around on a a few trails, although they ARE wet in places.


Are other types of pads available to these tektros?

Brian

This thread is about 6 months old. I'm fairly certain he's got his brakes sorted by now.