front fork losing air in the cold

Discussion in 'Cycling Equipment' started by Alvin Liau, Jan 22, 2003.

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  1. Alvin Liau

    Alvin Liau Guest

    Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when the weather's warmer.
    However, when it gets below freezing, the air seems to be leaking fast. For example, I'd pump it up
    to about 150psi, and about 5 minutes down the trail, most of the air will be out. When I screw the
    pump back on, the gauge will show about 40psi.

    I'm going to dig into it this week, but before I do that, any clues on what I should keep my eyes
    peeled for?

    Thanks. alvin
     
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  2. On Tue, 21 Jan 2003 12:12:27 +0000, Alvin Liau did issue forth:

    > Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when the weather's warmer.
    > However, when it gets below freezing, the air seems to be leaking fast. For example, I'd pump it
    > up to about 150psi, and about 5 minutes down the trail, most of the air will be out. When I screw
    > the pump back on, the gauge will show about 40psi.
    >
    > I'm going to dig into it this week, but before I do that, any clues on what I should keep my eyes
    > peeled for?

    My guess would be seals. If you've got a fork of that sort of age that's been used heavily then
    stuff is going to wear. Clean the fork down externally, take it apart, see what sort of state the
    seals are in and replace them if necessary.

    --
    Huw Pritchard | Replace bounce with huw | to reply by mail | www.secretworldgovernment.org
     
  3. Kinkycowboy

    Kinkycowboy Guest

    On Tue, 21 Jan 2003 12:12:27 -0500, "Alvin Liau" <[email protected]> wrote:

    >Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when the weather's warmer.
    >However, when it gets below freezing, the air seems to be leaking fast. For example, I'd pump it up
    >to about 150psi, and about 5 minutes down the trail, most of the air will be out. When I screw the
    >pump back on, the gauge will show about 40psi.
    >
    >I'm going to dig into it this week, but before I do that, any clues on what I should keep my eyes
    >peeled for?
    >
    >Thanks. alvin
    >
    Same problem caused the Shuttle Challenger crash; rubber seals losing their flexibility at sub zero
    temperatures. Replacing the seals might help if they're already old and worn, as new ones will have
    less work to do to close the gaps.

    Kinky Cowboy

    *Your milage may vary Batteries not included May contain traces of nuts.
     
  4. Alvin Liau

    Alvin Liau Guest

    "Alvin Liau" <[email protected]> wrote in message news:[email protected]...
    > Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when
    the
    > weather's warmer. However, when it gets below freezing, the air seems to
    be
    > leaking fast. For example, I'd pump it up to about 150psi, and about 5 minutes down the trail,
    > most of the air will be out. When I screw the
    pump
    > back on, the gauge will show about 40psi.
    >
    > I'm going to dig into it this week, but before I do that, any clues on
    what
    > I should keep my eyes peeled for?
    >
    > Thanks. alvin
    >
    >

    Just to close the loop in case anyone does a search in the future, we took a quick look at the fork,
    and couldn't find anything wrong. Replaced the screw-cap-assembly (where you pump the air in) with
    one from another fork, and still leaking.

    Since it was 11F that night and the garage wasn't much warmer, we punted and took it to the LBS. The
    mechanic took the fork apart, cleaned it, put it back together, and voila, no more leak. Good deal!

    Cheers, Alvin Liau
     
  5. Tj Poseno

    Tj Poseno Guest

    "Alvin Liau" <[email protected]> wrote in message
    news:<[email protected]>...
    > Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when the weather's warmer.
    > However, when it gets below freezing, the air seems to be leaking fast. For example, I'd pump it
    > up to about 150psi, and about 5 minutes down the trail, most of the air will be out. When I screw
    > the pump back on, the gauge will show about 40psi.
    >
    > I'm going to dig into it this week, but before I do that, any clues on what I should keep my eyes
    > peeled for?
    >
    > Thanks. alvin

    My guess is that the metal is expanding in the cold and the gaskets arent sealing right when it gets
    that cold and the air is leaking.
     
  6. Spot T. Rex

    Spot T. Rex Guest

    Metal Contracts in the cold and expands with heat.

    "Alvin Liau" <[email protected]> wrote in message news:[email protected]...
    > "Alvin Liau" <[email protected]> wrote in message
    > news:[email protected]...
    > > Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when
    > the
    > > weather's warmer. However, when it gets below freezing, the air seems
    to
    > be
    > > leaking fast. For example, I'd pump it up to about 150psi, and about 5 minutes down the trail,
    > > most of the air will be out. When I screw the
    > pump
    > > back on, the gauge will show about 40psi.
    > >
    > > I'm going to dig into it this week, but before I do that, any clues on
    > what
    > > I should keep my eyes peeled for?
    > >
    > > Thanks. alvin
    > >
    > >
    >
    > Just to close the loop in case anyone does a search in the future, we took
    a
    > quick look at the fork, and couldn't find anything wrong. Replaced the screw-cap-assembly (where
    > you pump the air in) with one from another
    fork,
    > and still leaking.
    >
    > Since it was 11F that night and the garage wasn't much warmer, we punted
    and
    > took it to the LBS. The mechanic took the fork apart, cleaned it, put it back together, and voila,
    > no more leak. Good deal!
    >
    > Cheers, Alvin Liau
     
  7. Matt O'Toole

    Matt O'Toole Guest

    "TJ Poseno" <[email protected]> wrote in message
    news:[email protected]...

    > "Alvin Liau" <[email protected]> wrote in message
    news:<[email protected]>...

    > > Hi! I have a 2001 Manitou Mars that's acting up. It
    performs fine when the
    > > weather's warmer. However, when it gets below freezing,
    the air seems to be
    > > leaking fast. For example, I'd pump it up to about
    150psi, and about 5
    > > minutes down the trail, most of the air will be out.
    When I screw the pump
    > > back on, the gauge will show about 40psi.
    > >
    > > I'm going to dig into it this week, but before I do
    that, any clues on what
    > > I should keep my eyes peeled for?

    > My guess is that the metal is expanding in the cold and
    the gaskets
    > arent sealing right when it gets that cold and the air is
    leaking.

    All the materials contract in the cold, including the gaskets. The gaskets also harden, which may
    affect their sealing too.

    Matt O.
     
  8. Spider

    Spider Guest

    "Matt O'Toole" <[email protected]> wrote in message
    news:<[email protected]>...
    > "TJ Poseno" <[email protected]> wrote in message
    > news:[email protected]...
    >
    > > "Alvin Liau" <[email protected]> wrote in message
    > news:<[email protected]>...
    >
    > > > Hi! I have a 2001 Manitou Mars that's acting up. It
    > performs fine when the
    > > > weather's warmer. However, when it gets below freezing,
    > the air seems to be
    > > > leaking fast. For example, I'd pump it up to about
    > 150psi, and about 5
    > > > minutes down the trail, most of the air will be out.
    > When I screw the pump
    > > > back on, the gauge will show about 40psi.
    > > >
    > > > I'm going to dig into it this week, but before I do
    > that, any clues on what
    > > > I should keep my eyes peeled for?
    >
    > > My guess is that the metal is expanding in the cold and
    > the gaskets
    > > arent sealing right when it gets that cold and the air is
    > leaking.
    >
    > All the materials contract in the cold, including the gaskets. The gaskets also harden, which may
    > affect their sealing too.
    >
    > Matt O.

    Not so for natural rubber. It's an odd material. :)

    Spider
     
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