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  1. #1
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    hydraulic disk brakes - noises?

    Howdy!
    this is my first bike with disk brakes, so I have no idea if this is normal or not. when the bikes rolls on uneven surface, I can hear two types of noises coming of the brakes (I think)

    1. mainly from rear - sort of random clear ringing or clinking noise - I suspect it is from sand and small debris thrown agains fast spinning rear disk rotor. Do not have the nose while on pavement, so it's probably it

    2. mainly from front - rattle. If I just stand next to bike and drop it from, say, few inches, i can hear the rattle as well, but not if brake lever is pressed. My guess the source of noise is disk pads - they are pinned but not fixed solidly, aren't they? so they can rattle around while not braking.

    any comments?
    the brakes are shimano M485, and bike is couple month old Giant Anthem

    regards
    nampla

  2. #2
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    "1. mainly from rear - sort of random clear ringing or clinking noise - I suspect it is from sand and small debris thrown agains fast spinning rear disk rotor. Do not have the nose while on pavement, so it's probably it"

    Since it's a random noise you are most likely right. A rythmic noise would likely be a slightly out of true rotor that brushes one pad or the other as it rotates through the caliper. And being the noise dispears on pavement it's almost certain. But you don't say what type and brand of bike you have. A full suspension bike can make noises in the rear that are similar if linkage and pivot bolts are loose. But the clear ring is likely the disc rotor.

    2. mainly from front - rattle. If I just stand next to bike and drop it from, say, few inches, i can hear the rattle as well, but not if brake lever is pressed. My guess the source of noise is disk pads - they are pinned but not fixed solidly, aren't they? so they can rattle around while not braking.

    Again another pretty good guess. On the M485 brakes the pads are heald in place with a pin, there is also a flat leaf spring sandwiched between the pads that is supposed to help keep them stable. Here is a link to a drawing that will show what I'm talking about... http://techdocs.shimano.com/media/te...9830648518.pdf ... item number 21 clearly shows the brake pads, retaining pin and leaf spring. If it bothers too much you can remove the pads and spring and very carefully bend the spring open a bit at the fold at the top. This will put a bit more tension on the pads when the spring is in place between the them. Otherwise you'll have to live with it. And sometimes spreading the spring doesn't help anyway. If you decide to try it just be VERY careful. The spring is very light and not that strong so be gentle. Also use care not to bend the legs of the spring that fit around the pad.

    Some pretty good guesses for your first set of disc brakes. It shows that you don't panic over little noises, and you analyze things well before you ask questions.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  3. #3
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    Many thanks for very informative reply!
    Regards
    nampla

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