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  1. #1
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    Brakes rubbing in hot weather

    Hi,

    My front brake has started rubbing but only when the weather is very hot. In the morning when I ride to work the brake is fine, no rub at all. In the afternoon it gets hotter and then I almost can't ride the bike anymore due to the brake rubbing to the extent that I can't turn the wheel anymore.

    The rear brake is suffering from the same but to a lesser extent.

    I was thinking that due to the higher temperature the brake fluid could expand and cause the calipers to extend. Or maybe they need bleeding?

    Any solution is welcome. They are Juicy 7's.

    Thanks.

  2. #2
    Never trust a fart
    Reputation: frdfandc's Avatar
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    They probably need bled. Especially if they have never been bled before.

    DOT brake fluid - which is what Avid uses - is hygroscopic. Meaning, brake fluid attracts moisture. Recommendation is once a year for brake bleeding.

    When too much moisture is in the brake system, it can change properties - liquid to vapor and vice versa. As it heats up, water will turn to vapor, expanding. As it cools down, it will turn back to a liquid.

    Either way, too much moisture is a bad thing.

  3. #3
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    Brakes rubbing in hot weather

    Ok! Thanks for the explanation.

  4. #4
    Addicted to 2 wheels
    Reputation: SugarHigh's Avatar
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    Same brakes and same thing happened to me on Sunday. I often ride in the heat though. It was 108. I rode in 113 the week before with no issues.

    Strangely, I just had the rear brake caliper rebuilt. It should be freshly bled.

  5. #5
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    Brakes rubbing in hot weather

    I think the system is overfilled. When hot crack the bleed screw and drain a little oil, if you need pull the lever only slightly. From my experience it will only need a little oil removed.

  6. #6
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    Brakes rubbing in hot weather

    Thank you all for the advice. I ordered a Avid bleeding kit and after using it the issue has disappeared completely. I had a lot of bubbles coming from the front brake so I think it was just air or vapor like one of you suggested.

    Overfilling wasn't the problem in this case. They've worked fine in all temperatures for about a year without me doing anything to them. The problem just recently started.

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