TotalKos

Hi there, I was hoping someone could help me get rid of the loud annoying squeal that comes from both my front and rear when I use my discs. I thought this would go away after awhile of use and it's been about 5 months now and it's still there. It's so loud I would almost rather not use the brakes and smash into stuff to stop. Oh yeah, it is only when there is humidity in the air or rain etc.

Raiyn

Discs do tend to squeal when wet. However that bit on humidity (if it's not a joke) is odd. Have you cleaned the rotors with denatured alcohol yet?

TotalKos

It is not a joke about the humidity. It happens anytime except super dry conditions. I haven't cleaned the rotor with denatured alcohol yet. What is denatured alcohol? I only know of rubbing alcohol, is that the same thing?

dooley

Try putting copaslip on the back of the pads.

nirvanaschains

Its pretty much the same thing, i just use rubbing alcohol, and its worked every time.

phantomcow2

Rubbing alcohol will work. you just use the alcohol and wipe down the rotor so that it gets any contaminants on the rotor off, without leaving a residue.

G4teamG

Like Raiyn says use denatured alcohol. You can buy it at Home Depot. I clean my rotors every 3 rides (50-75 miles) and no more squeal. Do not use rubbing alcohol it will leave a residue. Also, Use a clean shop towel. You'll be surprised how much residue is on the rotors. Good luck.

TotalKos

Thanks all for the help. I've just put some rubbing acohol on now and I'll pick up the other stuff tommorrow.

Raiyn

No. Don't put anything on the back of bicycle disc brake pads. I swear I don't know where you get this crap.

mtbikerinpa

copaslip/disc brake-quiet will help when used propperly to reduce chatter between the pad and the piston, but it is a solution to a non-problem. The pads will not chatter unless contaminated, and it is nice to have that indicator. Furthermore, when it is the slightest way misapplied, it will cause the pistons to stick(I had to rebuild a caliper where that happened.)
One other trick of the trade is heat. Periodically I find running a propane torch around the rotor(not center) to cook off any oily film works well. Observe for flame colors. When it is clean there will be no change. Not a normal operation, but I just spent a while getting fork oil(blown fork seals) off the pads and rotor. If done propperly, the torch and solvent can clean the pads as well. Not a beginner move though, so don't try it at home.

chris_pnoy

^ Hmmm... that is an interesting technique.

blue_neon

Just buy some disk brake cleaner, your all being too fussy.

Raiyn

How many times do I need to say this? The only thing you should be using on BICYCLE ROTORS is
DENATURED ALCOHOL

I swear every time we get a squealing disc brake thread on here we have to go through this again.
Look at your owner's manuals people.
It says Denatured (some will say rubbing) Alcohol. It does not say: Automotive Brake Cleaner, or gasoline, or even Moose Piss.
It says
DENATURED M**********ING ALCOHOL
It isn't about the rotor being affected its the pads

blue_neon

Calm down. The bike shop i'm working in uses disk brake cleaner, and we havn't had any problems / reports of squeeling brakes. Heck, bike shops even sell disk brake cleaner.

Raiyn

I'm cool as a cucumber.
Like I said. Check the manual. Besides denatured alcohol is cheaper and won't leave the residue that some auto brake cleaners will leave. These rely on the heat generated from a car's rotors to cook off

blue_neon

Anything sold in a bike shop is expensive. Thats my plane, I work in one, get paid, and get things cheap. Mwahahahaha. I got a new Bottom Bracket, hub service, new cables, pads, seat and powerlink for $25 AU .

Where do you get dentured alchol from anyway?

blue_neon

ohhh and add on $5 and I got a truing wrench

[bEn]

I've seen you say that a lot of times when it comes to threads like these....

Raiyn

Hardware and camping supply stores will generally have it

Roasted

Is this recommended for us bikers out here who do not have disc brakes? (regarding the outside walls of the rim where the pads rub).

blue_neon

I doubt very much so.

phantomcow2

I use rubbing alcohol on the rims, seems to work. Some say it eats at the rubber, so i wipe off the rims when i change tires.

Raiyn

You can. It evaporates quickly enough not to make a difference to your tires or pads. If your rim brakes are squealing it's usuallly either a toe-in issue or pad glazing both of which are easy fixes

myca

I have a pair of Hayes HFX9 hydraulic brakes and experience the same deafening squeal. It happens “all the time”, whether the conditions are dry or wet. I’ve used alcohol to clean the disc and the pads which seem to eliminate the problem for about two miles worth of riding but then it’s back to the squeal. It’s gotten to the point where it actually vibrates the bike while braking. The problem continues despite changing the pads every 700 miles or so. I’ve had the brakes serviced at a few bike shops to no avail. Would I be throwing my money away by replacing the disc as well as the pads? I’m realizing it’s hard to find a definitive answer to this problem. Any additional advice appreciated.

cydewaze

I found that a little teflon lube gets rid of the squeel.




Just kidding...