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  1. #1
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    I need help with squealing Avid Mech Disc brakes

    Damn, I'm getting frustrated... As much as I love the stopping power and on-th-fly adjustability, I hate that screeching/squaling noise every time I tough the brakes!

    I know if the calipers aren't aligned properly with the rotors, you get mad squealing.

    For starters, these pads are relatively new and genuine AVID pads. I've cleaned the pads and rotors and rinsed down everything (no soap or detergents). I then took fine-grit sandpaper (like 220 or something) and lightly rubbed the rotors and pads. I then installed the brake calipers. Hopefully this is right: tighten the pads against the rotors first and then tighten the bolts on the calipers to the frame and then dial the pads away from rotors according to personal brake lever pressure (using Avid SD5 levers).

    My pads seem to have uneven wear (probably because I didn't align them properly the first time around several months ago)... Could this be the problem? If you guys agree that I've installed these properly and it must be the uneven pads, can I get away with using another less expensive brand of pads? Damn, those AVID pads are pretty expensive!

  2. #2
    sixsixtysix
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    The pads always wear at a slight angle because of the way the outside pad pushes the rotor into the inside pad. As for setting them up, you did the 2/3 - 1/3 spacing when you tightened the pads against the rotor to adjust your caliper? You didnt touch the pad surface with your hands did you? Mine squeeled once when i did that, but I just took a blow torch to the pads briefly and it solved it. Sometimes Avids just squeel though.

  3. #3
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    probably alignment

    I've had the same prob with Avid mechs. Squeals all of the time. Replaced pads, new rotor, etc. I recently put on a set of backup wheels and re-aligned calipers - problem went away completely. Got my main set of wheels back on, re-aligned calipers again (and again) - squeals like a stuck pig no matter what I do. Drives me crazy, but I'm not running a set of backup wheels just to eliminate the problem.

  4. #4
    nnn
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    Quote Originally Posted by tonyl
    I've had the same prob with Avid mechs. Squeals all of the time. Replaced pads, new rotor, etc. I recently put on a set of backup wheels and re-aligned calipers - problem went away completely. Got my main set of wheels back on, re-aligned calipers again (and again) - squeals like a stuck pig no matter what I do. Drives me crazy, but I'm not running a set of backup wheels just to eliminate the problem.
    In your case it's likely a case of resonance of some kind. You could try to dampen vibrations through the wheel or caliper somehow see if that helps.

  5. #5
    Nouveau Retrogrouch SuperModerator
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    Once the pads wear unevenly it is difficult to readjust the caliper properly.

    If you do not keep the inside pad adjusted as close as possible to the rotor they are more likely to squeal. I do this and my pads wear nearly dead flat. The spring clip can also contribute to uneven wear. I do not use them if I can get away with it.

    The EBC Gold and Galfer pads tend to be quieter than the stock Avids in most conditions. YMMV
    mtbtires.com
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  6. #6
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    This is a fix used in a lot of cars;
    You can buy small anti-squeal kits for cars, basically it's a very thin rubber sheet.
    You could try cutting these pieces the right size and installing between pad and piston..?

  7. #7
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    Can you tell me the 2/3 - 1/3 spacing technique? Most likely I may not have done it properly to begin with which caused increased uneven wear on new brake pads... I'm going to get new pads and try to do this properly.

    Also, can anyone vouch for other brands of brake pads? I tried looking for Galfer but came up with a lame website and nothing more. I can probably get 2 pair for $35 on ebay, but if I can get another brand for like $25 then I'm game at this point. Besides, I read an article saying that most OEM products tend to use lesser quality materials as they receive a higher mark-up, whereas non-OEM brands tend to put more research and quality into their products as to compete and be better than OEM (this is a general statement), but does hold water when you think about it.

  8. #8
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    sorry this is a repeat, but didn't realize it posted above, so here goes again...


    Can you tell me the 2/3 - 1/3 spacing technique? Most likely I may not have done it properly to begin with which caused increased uneven wear on new brake pads... I'm going to get new pads and try to do this properly.

    Also, can anyone vouch for other brands of brake pads? I tried looking for Galfer but came up with a lame website and nothing more. I can probably get 2 pair for $35 on ebay, but if I can get another brand for like $25 then I'm game at this point. Besides, I read an article saying that most OEM products tend to use lesser quality materials as they receive a higher mark-up, whereas non-OEM brands tend to put more research and quality into their products as to compete and be better than OEM (this is a general statement), but does hold water when you think about it.

  9. #9
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    Avid has the PDF of the 6 step install on their site free to download. Download that and make sure you follow every step. Avids as sweet brakes only if setup properly, otherwise they may feel like v-brakes!

    There is a diagram of the 2/3 and 1/3 spacing on that PDF. The 2/3 gap should be on the inside (stationary pad) and the 1/3 on the outside (moving pad).

  10. #10
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    2/3, 1/3 Important!

    The 2/3rd and 1/3rd Avid "rule" is an important one for getting the brakes to function as designed. As frankenbike said, download the small and easy-to-understand manual from the website. Follow it step by step, and you should have a set of outstanding disc brakes. I went so far as to use a Sharpie and write the number "2/3" on the appropriate side of the caliper so I kept the ratio correct.

    Michael

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