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Old 05-26-08, 02:56 PM   #1
bryroth
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Wheel Chatter - and I can't ride because of it. What is it?

I'm new to bike mechanics, in the past I've been a doosh and paid for everything. Now I've caused a problem that has effectively stopped me from biking (today at least).

Here is the thing. I've been having a hell of a time getting my brakes the way that I want them. The latest thing I did was install Kool Stop salmon-colored pads in the front. To eliminate the squeal, I've sanded them a bit and toed them in.

Now when I apply the front brakes, nothing happens at first, then there is a LOUD machine-gun-tempo squeal and the bike stops like it has anti-lock brakes. That is, it locks then unlocks then locks then unlocks, like a machine gun. It really jolts me if I'm going faster than 8 miles per hour. Which I would really like to do again someday. Also, I can't reduce my speed. I can only stop. For example, if I'm going 20mph and want to go 15mph, I don't have that option. All I can do is have the bike try and lock the tire to bring me to a complete stop.

What the hell did I do? How can I un-do it? I am REALLY trying to avoid paying $30 (that's how much my lbs/chain charges) to get my front brakes installed correctly. And yes, that's $30 even if I supply the pads. *******s.

So I paid way to much for this bike to ruin it with $10 worth of brake pads.

I have Avid Shorty 4 cantilever brakes:


I have Kool Stop Supra 2 pads:


Help. Please.
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Old 05-26-08, 03:15 PM   #2
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I too have Avid Shorty 4 brakes. Sounds like you toed them too much. These brakes only need a slight bit of toeing.
Also, did you wipe the rims with a degreaser or solvent? That will also cause the problem you described.
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Old 05-26-08, 03:35 PM   #3
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What if you swap then so that the "long" part is facing the other direction?
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Old 05-26-08, 04:50 PM   #4
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Thats a fairly common problem with cantilevers. Like ronh said, play with the toe a little and wipe down the rims. The kool stops have a built in toe guide. You'll notice that back of the pad has a tiny triangle of rubber that sticks out. If you adjust the brakes so that the back tip touches at the same time as the front of the pad, you should be in good shape. Other things you can try: New rims (I replaced a worn ceramic coated rim with a new open pro and the chatter went away), different brakes (i've seen the avid shorties mentioned a lot in brake chatter discussion. i don't have any good recommendations for alternatives though.), or just try to modulate your braking more. Try to give yourself a little extra room to stop so you can slow down more slowly.
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Old 05-27-08, 06:20 AM   #5
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Thanks for the replies. Bill K - I tried to switch the direction of the pads but all it did was produce a higher pitch squeal before bouncing. I'd say it went to a high C from a middle C. I wiped down the rims and played with the toe angle forever. I just must not have the touch. I'm biting the bullet and bringing them in to the shop today.

It seems like it should be easier to replace the pads. I would upgrade the brakes, but it's such a simple mechanism that I don't see how it could possibly be improved upon.

Anyway, thanks for trying.
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Old 05-27-08, 05:24 PM   #6
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I've found Kool Stop salmons to be very grabby on certain rim surfaces. I had this same problem on a Nashbar touring frame I built up. The solution (I got this by searching a few archived BF threads) is a fork mounted front cable stop. If you can mount it on your fork, I'm 99% certain it will solve your problem. My local master mechanic didn't think it would work, but it did.

http://harriscyclery.net/itemdetails.cfm?ID=1805

Check around to see if your LBS's have any stock, as it will be much cheaper than ordering online + shipping.

Won't work on a suspension fork, unfortunately.
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Old 05-28-08, 08:32 AM   #7
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What fork are you using? My threaded 1" fork squeals like crazy in the rain. Super flexy. I've heard of Short 4's also notoriously being loud. My remedy would be Aztec 2 brake pads. They're a little softer and they might absorb/ cancel out the vibrations enough to be quiet. my $.02.
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