brake squeal... what causes it & how do you cure it?

[jax13]

as title folks. I've never given it much thought until tonight but what actually causes brake squeal on bikes?

my best guess is when there is slippage between rim & pad resulting in a higher pitched version of squeaking your finger down a window.

my technical, potentially over the top guess would be something along the lines of the pads not hitting the rim square causing them to vibrate the rim between them / a non-true rim bouncing between the pads.


the other thing is... how do you cure it? i've not had brake squeal in years but recently i've been getting it with basic avid V pads on arch rivals which do the stopping duties pretty well (although not as good as they should imho) but they have started to make an ungodly howl when stopping from low speeds.

 

[craiga]

I think the main tip to stop it, as I remember from Sheldon Brown, is to set the pads up with a toe in, ie the front of the pad touches first

 

[ere-tis]

I had horrible brake squeal on my Tricross so I set the pads up with a little toe in and it cured it.

 

[legrandefromage]

A little camel toe-ing will help

 

[konacarl]

Sqealling

We used to go to get my Grandad to oil our rims when we were kids! It stopped the squealing but didnt do much for the stopping power.

 

[jax13]

exactly how much toe do people use? I tend to go for 2 layers of cereal box thickness card... too much? too little?

with saying that, my pads have probably either shifted slightly or i've worn the toe down ahead of the rest of the pad which may be causing it.

 

[feetabix]

about one mm has always done it for me....i keep a petrol reciept in my pack, folded up a few times into a 'prong' that i can set the pads against....having said that, a good bout of squeal keeps you off the brakes and up's your average speed a bit!...

 

[ere-tis]

having said that, a good bout of squeal keeps you off the brakes

and negates the use of a bell

 

[Groundoggy]

First I would look at the pads to see how they are wearing. Are they wearing evenly? Are they glazed? Is the rim surface clean? Take a scrubby pad and some degreaser followed by soapy water to clean all braking surfaces.

Pad adjustment is pretty critical. You want as close to a 90 degree angle as you can get when the brake pad hits the rim. If it's a non-threaded type post I mount it about midway - maybe a bit extra out the pad side.

A cereal box top folded in half is what I use for toe-in - usually with a bit of pressure applied at the brake lever once things are reasonably tight.

For best results - start with new pads and clean rims. Hard to beat the black/salmon Kool Stops IMO. It's a good mix for all weather conditions.

If you don't ride in wet full on salmon pads are the ticket. Similar (identical?) to the legendary Scott-Matthauser compound it's still the top brake pad surface out there.

 

[unkleGsif]

A match is what I use to set toe in.... coz I always have a box of matches with me on rides, for lighting my pipe/woodbine/rollie/spliff/crack-pipe/petrol-bomb*

*delete as appropriate

G