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Thread: Avid BB7 Chirp

  1. #1
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    Avid BB7 Chirp

    I recently built a bike with Avid BB7's and after riding the bike for about 20 miles, my front disc brake started chirping when braking. I've ridden the bike for over 200 miles now and the front disc still chirps when braking. The rear disc never makes any noise, practically silent, though I do admit I haven't used it anywhere near as much as the front disc.

    The front disc brakes very well, the noise seems to be the only problem. I've re-installed it to make sure I didn't do anything wrong but the noise persists. Does anyone know what the problem might be, or is this normal?

  2. #2
    Dough Mestique
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    Try cleaning the disc with rubbing alcohol and a lint-free cloth.

    BL


    www.lanterne-rouge-bikeworks.com

    "Next time, I will not make the same mistake twice!"

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    Senior Member sirtirithon's Avatar
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    My Avid BB7's do it too. Im looking forward to reading the replies. My Avid 5's never chirped or chattered.

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    did you bed in the pads correctly? 10-20 lever pulls without coming to a complete stop? a complete stop puts more pad material in one spot during break in.

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    If you have the bike in a stand (or upside down) are you seeing the rotor rub the pads when you spin the wheel? In addition to cleaning the rotor and checking pad placement, you may also want to check the wheel placement. My front hub is a little off and my BB7s will make a little noise if I don't have the wheel installed just right.

  6. #6
    Old. Slow. Happy. MileHighMark's Avatar
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    Are you running the stock pads? If so, you may want to consider replacing them with Avid's organic pads. Much, much quieter.
    GRAVELBIKE.COM - ride everything

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    coprolite fietsbob's Avatar
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    I only get noise at very low speeds, in front , then I use the back one..

    Avid ships the organic pad type in them , when new?
    not the metallic sintered type?
    Last edited by fietsbob; 04-03-12 at 03:48 PM.

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    Old. Slow. Happy. MileHighMark's Avatar
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    Quote Originally Posted by fietsbob View Post
    I only get noise at very low speeds, in front , then I use the back one..

    Avid ships the organic pad type in them , when new.
    not the metallic sintered type.
    Really? Every single set of BB7s that I've purchased over the past 4-5 years have come with the metallic pads.

    Avid shows metallic pads as OE on their site:
    http://www.sram.com/avid/products/bb...th/term-id/289
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    Qr tight? Hub tight? Headset tight? Did you use new rotor and pads?

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    I've done everything everyone has mentioned, there's no rub when spinning the wheel. Everything was installed brand new. Mine came with metallic pads, I might change over to organic pads in the future but I don't think that's the problem, because the rear disc makes no noise at all. fietsbob mentioned his front disc is noisy at low speeds, mine chirps a lot at low speeds, the chirp quiets down at higher speeds and the noise becomes a light squeal. I'll try re-torquing the disc bolts to see if that does anything, I'll report back.

    I'm sure there's a reason, I hope I find it soon enough

  11. #11
    coprolite fietsbob's Avatar
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    Are the pads them selves color coded , which is which?

    I look down and all i see is the return spring tweezer.
    Last edited by fietsbob; 04-03-12 at 03:50 PM.

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    Old. Slow. Happy. MileHighMark's Avatar
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    The organic pads come in two flavors -- steel and alloy backed. The organic ones that I've used have been marked with an "O" on the back plate.
    GRAVELBIKE.COM - ride everything

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    coprolite fietsbob's Avatar
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    Man,that means taking then apart. the mild squeak does not bother me, just the OP.
    I can wait till I replace them.

    saw some replacement pads banded, mixed organic central and metallic on the edges.
    didn't come from Avid, I think Clarks from England, they probably source in China too..

  14. #14
    Senior Member skiph's Avatar
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    Picked up this idea on another bike forum site:

    Are the lower edges of the front brake pads hitting on the rotor 'spokes' when you apply the front brake?

    That is, are the lower edges of the brake pads running below the actual braking track of the rotor?

    In some other posts on another site...the caliper wasn't far enough from the axle center relative to the outer edge of the rotor, so the pads were hitting on the rotor 'spokes' when they were applied.

    The guy with the problem used some spacer washers to move the caliper farther out along the rotor's braking track so the lower edge of the pads were clamping fully on the rotor braking surface, no longer hitting the rotor spokes.

    To test if the pads were now riding fully on the braking track, he drew a radial line in a couple of places on the braking track with a Sharpie felt tipped marker, and could see where the black ink was rubbed off.

    Then another poster said to watch the TOP edge of the pads to see they did not develop a ridge if the top edge was now off the outside of the rotor. He suggested just sanding them flat from time to time if that was the case.

    Hope this helps.

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    ^^^
    I discovered once that a rotor wasn't centered, so if you viewed it from the side you'd see it going up and down a bit. I removed the wheel, loosened the screws, rotated the disc against the screws, and retightened. Much better.

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    Related question - I have a BB7 on my front wheel, and it has started making a grinding sound as if dirt/sand is trapped in the pad. Should I be cleaning the pads with any frequency? Any other explanations for a grinding sound?

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    Quote Originally Posted by skiph View Post
    Picked up this idea on another bike forum site:

    Are the lower edges of the front brake pads hitting on the rotor 'spokes' when you apply the front brake?

    That is, are the lower edges of the brake pads running below the actual braking track of the rotor?

    In some other posts on another site...the caliper wasn't far enough from the axle center relative to the outer edge of the rotor, so the pads were hitting on the rotor 'spokes' when they were applied.

    The guy with the problem used some spacer washers to move the caliper farther out along the rotor's braking track so the lower edge of the pads were clamping fully on the rotor braking surface, no longer hitting the rotor spokes.

    To test if the pads were now riding fully on the braking track, he drew a radial line in a couple of places on the braking track with a Sharpie felt tipped marker, and could see where the black ink was rubbed off.

    Then another poster said to watch the TOP edge of the pads to see they did not develop a ridge if the top edge was now off the outside of the rotor. He suggested just sanding them flat from time to time if that was the case.

    Hope this helps.
    Quote Originally Posted by p2templin View Post
    ^^^
    I discovered once that a rotor wasn't centered, so if you viewed it from the side you'd see it going up and down a bit. I removed the wheel, loosened the screws, rotated the disc against the screws, and retightened. Much better.
    That's interesting, I checked the brake mark on my front rotor and it's hitting the spokes very very slightly in three places. I'll re-center the rotor and report back if that fixes the problem.

  18. #18
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    I re-centered the rotor and that pretty much completely got rid of the noise, thanks!

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