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Can't fix disc brake squeal!

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Can't fix disc brake squeal!

Old 06-05-20, 10:31 AM
  #1  
rbrides
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Can't fix disc brake squeal!

I have a road front wheel + tire + disc brake setup that squeals and I can't fix it.

I have gravel front whee/tire/disc that I put on the same bike with the same caliper and pad but that disc does NOT squeal at all. That tells me it is the disc, not the brake caliper or pads.

I have repeatedly cleaned that squealing disc with rubbing alcohol but it does not solve the problem.

What are other causes of disc brake squeal? What are other solutions to eliminating brake squeal?
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Old 06-05-20, 10:44 AM
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dsbrantjr
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Rubbing alcohol is not a particularly good solvent for petroleum-based contaminants, try a spray of Brakleen, available at auto parts stores.
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Old 06-05-20, 11:08 AM
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Try swapping the non squealing disc to the other wheel and report back. Id be interested in the result :-)

I have a bike with post mount discs that squeal when wet. No amount of cleaning or breaking in helps. Organic pads helped a little.
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Old 06-05-20, 05:19 PM
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fietsbob 
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Pads glazed? (take them out & look?) have carborundum sand paper to remove it?
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Old 06-05-20, 06:13 PM
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I had a bike that I just couldn't control the squeal, especially when wet. Thank goodness someone stole it from me and I hope that squealing is driving them nuts. Kind of like "The Tell Tale Heart".
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Old 06-05-20, 11:34 PM
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My brand new bike squealed (front wheel only) when I picked it up in the shop. I asked the guy why it was doing that and if it was nomal and he said it was and the way to get it to stop is to go full speed and clamp down hard on the brakes. Then repeat this about 15 times. (I think he said 15).

Normally I would think this is crazy but when I looked up how to stop my Audi's breaks from squealing, I found that it was the same way. It's recommended to get up to about 60 mph and slam on the brakes (somewhere safe of course) enough so that you engage the antilock system. Then repeat a few times.

When I brought my car in for service, I asked the service writer how to stop it (as a test), he said the same thing. I guess for the performance brakes on my car, if you don't brake hard enough, a layer of whatever builds up. I'm not sure how true this is as it only squeals when it's cold out.

Anyway, maybe something to try with your brakes.

Oh and the other solution that was recommended for my car was to get different brake pads.
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Old 06-06-20, 01:33 AM
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How's your pad thickness? How is the pad surface? Shiny glazy sheen?

Organic wears faster, fades sooner, but is much quieter than sintered (metal.)

I get about 1500 all weather miles on front organic pads.

The other wheel probably does not squeal because the pads & rotor are not worn in together as well & won't be for some time. Notice less good brake function when you first do a wheel swap? The reason is the pads & rotor wear to a matched fit as a matter of function. If all else looks well, work 'em hard & get 'em warm once in a while & see how that goes.

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Old 06-06-20, 03:24 PM
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Came across this last night: https://www.canyon.com/en-us/support...sc_brakes.html
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Old 06-09-20, 10:37 AM
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Originally Posted by dsbrantjr View Post
Rubbing alcohol is not a particularly good solvent for petroleum-based contaminants, try a spray of Brakleen, available at auto parts stores.
Brakleen worded great. Thanks. It took me a few days to get to the auto parts store so I apologize for the delay in responding.
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Old 06-09-20, 10:38 AM
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rbrides
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Thank you for posting, Racing Dan
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Old 06-09-20, 10:39 AM
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rbrides
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Thank you for posting, fietsbob.

Brakleen did the job.
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Old 06-09-20, 10:45 AM
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rbrides
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Originally Posted by Jtsweeep View Post
Yes, this has been my standard brake servicing/cleaning routine. I always used rubbing alcohol to clean the disc but, lately, it was not eliminating the squeal. Brakleen has now done the job.
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Old 06-09-20, 10:48 AM
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Thanks everyone for your replies and comments. The process from Canyon is the way to go (don't take short cuts) but use Brakleen on the discs.
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