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One of my bikes has cantilever brakes on chrome rims. With dual compound Koolstop Eagle 2 pads braking is adequate and I can rely on the front brake at least in the dry.

The back brake squeals like a stuck pig. I could easily make it stop, but it's a much more effective warning than a bell or a shout when someone steps out in front, or when the lights change while passing stationary traffic. I like this feature.

I'll restrict this to dry conditions as wet rims obviously change the behaviour. I can drag the brake lightly without squealing, or lock up the back wheel, but intermediate braking almost always produces a loud squeal for quite a range of pressure. My issue is the almost. This morning was dry, and I tested over a number of stops without using the front brake. All were from around 20 km/h (10--15miles/hour) and were planned but fairly sharp stops. Excluding when I skidded the back wheel on a dirty bit of road, it squealed with no thought on about 80% of the stops. On the other 20%, no modulation could produce a squeal. Why?

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  • I've seen How do I make my rim brakes stop squealing?, but that's not what I want to do.
    – Chris H
    Nov 10, 2016 at 13:45
  • So just to be clear, your asking why it squeals 80% of the time? Or why it doesn't squeal 20% of the time?
    – ebrohman
    Nov 10, 2016 at 14:36
  • Why not 20%. (@ebrohman)
    – Chris H
    Nov 10, 2016 at 15:41

2 Answers 2

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I have cantilever brakes on my bike so I know the feeling. They just seem much more likely to squeal than any other type of brakes I've owned. In the spring I had a bit of squealing. I cleaned off the rim, readjusted everything (cables, toe-in, etc.), and sanded down the brake pads a bit and everything seemed to be pretty good.

I also think it's something to do with the temperature. Ever since the temperature started to drop, my front brake (also cantilever) has been squealing a lot. Even during the summer the first few times I would use my brakes they would squeal, but once they warmed up they seemed to work fine. I wonder if anybody makes a special brake shoe using a different rubber for cold weather braking.

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  • The warming up is interesting. While both the first and last stops squealed on this morning's test, the penultimate stop was quite long - probably enough for them to cool down.
    – Chris H
    Nov 10, 2016 at 14:11
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I have a bike with Avid Shorty Ultimate cantis and have had the same problems in the past. I'd start by cleaning your wheels off with rubbing alcohol or acetone to make sure there isn't grime and oil from the road causing the squeal.

Your brake pads might be contaminated already in which case I'd say sand a thin layer off the top and try putting them back onto clean wheels and try again. Make sure to sand the pads perpendicular to the way they will grab the wheel.

Next thing is to make sure you have the right "toe-in" on the pads. Basically, you want them pointing slightly inward so that the front of the pad grabs the wheel first.

If all else fails, you might take it to your LBS and see if they have any tricks up their sleeve.

Also, check out this question/answer as it may be helpful.

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  • I could make the sound stop if I wanted to. I want to make it more predictable.
    – Chris H
    Nov 10, 2016 at 14:12

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