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  1. #1
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    Reputation: gticlay's Avatar
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    I don't get why my XTR caliper is making noise in the rear

    I've only been riding it in the mud but today it was cold enough where all the mud was frozen. The brake would make a pretty loud noise (like old cantis did...) to where I think the whole frame was vibrating too. When there was enough braking on a trail for it to heat up some, the brake went silent and felt great... but once it cooled back down it was back to making noise. Front is silent.

  2. #2
    Meh.
    Reputation: XSL_WiLL's Avatar
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    Out of the pads ideal operating temperature range? Condensation building up on the rotor from the temperature difference?

  3. #3
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    simple happens all the time.

    The brake rotor heats up, frozen roost hits the rotor, the roost melts voila, wet rotor squeal.

    When it gets really cold the snow will roost onto the rotor, melt, then freeze, now we have an ice rotor. Absolute Zero brake force, since no friction no heat, no melty the ice.

    just grab on with two fingers, squeeze has hard as you can (usually not a problem cause of the panicy feeling of no brake), can take about 50 yards to finally bust off the ice and bang brake is on.

    Fortunately the front is pretty much unaffected by the roost, so is usually okay, but hit a snow drift!!!!

  4. #4
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    Reputation: flipnidaho's Avatar
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    also, if you've been riding quite a bit in the mud, make sure that your rotor/pads are not too worn (one or the other may need replacing)...

  5. #5
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    Quote Originally Posted by flipnidaho
    also, if you've been riding quite a bit in the mud, make sure that your rotor/pads are not too worn (one or the other may need replacing)...
    I have been riding only in the mud - can't even see my bike when I'm done The local shop said the stock pads are noisy and I should put some non-metallics in. The rear rotor might be a littlel glazed too - Maybe I should take it to my scotchbrite wheel??

  6. #6
    Double-metric mtb man
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    If it is colder, I've found you can easily get some squeal...in my longer night rides these days (Alberta, Canada right now means that any ride after 4:30 pm is a night ride and cooler to down-right cold) I can get both my brakes howling due to frosting up. After a short section on the brakes, they go back to being silent (once they are heated up again).

    Check the rotors and pads for cleanliness, wear and glazing. If dirty, get 'em cleaned up. If you suspect glazing, a little sanding will help. If worn, replace what needs replacing.
    As if four times wasn't enough-> Psycho Mike's 2013 Ride to Conquer Cancer Page

    Moran? Let your opinion be free -> F88me

  7. #7
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    OK, I think I got it fixed. I used industrial scotchbrite on the disk - just pedaled on the stand and held it against it to slightly score the surface. I removed the pads and sanded them a tiny bit and cleaned them up with a toothbrush. I also noticed that the inboard piston was way out the outboard piston was all the way in. So I took a piece of cardboard and pushed in the inboard one with a screwdriver. I then held the piston in and CAREFULLY pulled the lever - POP! The outboard piston kind of broke free and pushed out a little. So I pushed it back in and did the same thing a few times. I think it was stuck and now they both actuate the pads evenly. So I put the stuff back in and test rode it on the street (I live on a hill...) and it seems to be fixed. (fingers crossed).

  8. #8
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    Ah the infamous sticky piston.

  9. #9
    Double-metric mtb man
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    Glad to hear you've got it licked
    As if four times wasn't enough-> Psycho Mike's 2013 Ride to Conquer Cancer Page

    Moran? Let your opinion be free -> F88me

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