What's causing my bike brakes to squeal?

[Sukhoi]

I recently repositioned the brake pads on my bike (5 year old Trek 800) to get them better contact with the rim (the pads were a little low), and now my bike is squealing horribly whenever I break. At first I was only having problems with the front-right pad, but now the back brakes are squealing too.

 

[MajesticMoose]

technically a high frequency vibration, but i don't know what is causing that to occur, sorry...

 

[LuNoTiCK]

Maybe you need new brake pads? Or there may be dust, try cleaning the rims and brakepads real good. I'm not really sure, just giving ideas.

 

[shiner]

Have you recently run over a screamapillar?

 

[Don Vito Corleone]

You need to ensure the pads are properly toed-in - this is probably the explanation. They have to be set up so that the leading edge of the pad touches the rim first. Here is a beginner's guide to toeing in your brakes.

 

[Rallispec]

Originally posted by: shinerburke
Have you recently run over a screamapillar?

lol

 

[geno]

Dunno, try some WD-40, that usually works on squeaks



geno's disclaimer *do not use WD-40 on your brakes, you will end up diving head first into a bush when you try to use them, finding that they will do nothing...*

 

[yakko]

Originally posted by: Don_Vito
You need to ensure the pads are properly toed-in - this is probably the explanation. They have to be set up so that the leading edge of the pad touches the rim first. Here is a beginner's guide to toeing in your brakes.

Good link.

 

[Ranger]

Try here
link

Andy

 

[udonoogen]

Originally posted by: shinerburke
Have you recently run over a screamapillar?

simpsons? i think i saw that episode. =) LOL. good episode

 

[bacillus]

Quote

--------------------------------------------------------------------------------
Originally posted by: shinerburke
Have you recently run over a screamapillar?
--------------------------------------------------------------------------------
hehe

 

[B00ne]

the reason for the squeeking is usually that u mounted the pads wrong. To mount them so they dont squeek u have to mount them so that they are not parallel to the rim but in an angle instead. The tip of the break pad should touch the rim first. To mount them right u do it like this. When the tip of the pad (in running direction of the wheel) touches the rim, the rear part should still have about a millimeter of air. For instance, before tightening the bolts, press the break pads against the rim ( so that the face of the pad touches plane against the face of the rim) but put a small coin between the rim and the end of the pad, then tighten - that should do the trick...

 

[Sukhoi]

Ah, thanks guys. I'll try the coin trick and hopefully it'll work. I figured it was something I changed with the positioning of the pads, but I had forgotten about toe-in.

 

[Fausto]

Originally posted by: Sukhoi
Ah, thanks guys. I'll try the coin trick and hopefully it'll work. I figured it was something I changed with the positioning of the pads, but I had forgotten about toe-in.

</me smacks Sukhoi with a sweaty pair of cycling shorts so he won't ever forget about toe-in again>

 

[Amused]

I've also noticed that break pads can sometimes squeal even if toed in correctly. They way to stop this is to rough them up with some sandpaper or a nail file.

But yeah, it sounds like when you repositioned them, you didn't toe them in correctly.

 

[Don Vito Corleone]

Remember that even V-brakes require toeing-in. Shimano initially claimed this was not necessary (and I believe the installation instructions still indicate they should be set up parallel to the rim), but their service bulletins now correctly recommend toeing-in. I know I recommend it, after more than one mountain ride in which my brakes shrieked like the demons of hell!

 

[Sukhoi]

Yep, I added a little toe-in, and no more squeaking!

 

[brtspears2]

If toe-in trick with the coin doesnt work, what next?

I was told to clean the rims with water, no help.
Re-did the toe in, no help.

Whats the next step?

 

[Sukhoi]

*This is newbie advice and comes with no warranty. *

I'd try cleaning the rims with various cleaners (rubbing alcohol, acetone, xylene based, etc.) and see what you can get off. Then rinse it with water.

 

[brtspears2]

Rubbing alcky on, water off....

Now instead of a squeak, I hear rubber slipping like crazy... and a much more LOUDER squeak....

 

[Evadman]

Originally posted by: brtspears2
If toe-in trick with the coin doesnt work, what next?

I was told to clean the rims with water, no help.
Re-did the toe in, no help.

Whats the next step?

Maybe I am being dence, but did you try a can of good brake cleaner?

Some pads just plain suck, and will always have some squeek until good and worn.

 

[brtspears2]

Originally posted by: Evadman

Originally posted by: brtspears2
If toe-in trick with the coin doesnt work, what next?

I was told to clean the rims with water, no help.
Re-did the toe in, no help.

Whats the next step?

Maybe I am being dence, but did you try a can of good brake cleaner?

Some pads just plain suck, and will always have some squeek until good and worn.

Pads never squeeked until now... brake cleaner?

 

[kherman]

Originally posted by: shinerburke
Have you recently run over a screamapillar?

This is a very common problem in heavily wooded areas.

 

[brtspears2]

More help please.

I've toe'ed in. I've cleaned the rim with some alcohol. I've cleaned the pads with alcohol. It still squeeks!
Pads have more than plenty of material left.... I don't want to take it to the store for them to take another $20 away from me.

 

[brtspears2]

I give up. I went to store, bought brand new severe weather Kool Stop brand brakes. Put them on, sanded the rims again.

There went another $15.