Rear wheel off-center at brake bridge

Discussion in 'Cycling Equipment' started by Glenn Ammons, Feb 9, 2003.

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  1. Glenn Ammons

    Glenn Ammons Guest

    I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that it
    is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
    string test tells me that the rear triangle is properly centered, and I've used the Park tools to
    check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
    judging by eye.

    My theory is that the dropouts are both bent by the same amount, so that the wheel sits
    cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
    should check first?

    Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
    was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
    triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
    4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right side
    of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in the
    chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.

    Thanks. --glenn
     
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  2. Phil Holman

    Phil Holman Guest

    "Glenn Ammons" <[email protected]> wrote in message =
    news:[email protected]...
    > I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that
    > it is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
    > string test tells me that the rear triangle is properly centered, and I've used the Park tools to
    > check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
    > judging by eye.
    >=20
    > My theory is that the dropouts are both bent by the same amount, so that the wheel sits
    > cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
    > should check first?
    >=20
    > Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
    > was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
    > triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
    > 4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right
    > side of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in
    > the chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.
    >=20
    > Thanks. --glenn
    >=20
     
  3. Glenn Ammons wrote:

    > I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that
    > it is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
    > string test tells me that the rear triangle is properly centered, and I've used the Park tools to
    > check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
    > judging by eye.
    >=20
    > My theory is that the dropouts are both bent by the same amount, so that the wheel sits
    > cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
    > should check first?
    >=20
    > Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
    > was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
    > triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
    > 4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right
    > side of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in
    > the chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.

    Try putting the wheel in backwards, see if it's still off to the same=20 side of the frame. If it
    isn't, the problem is an improperly dished=20 wheel. If it is, the problem is the frame.

    Sheldon "Check The Wheel First" Brown +-------------------------------------------------+
    | I=92ll be appearing with the Sudbury Savoyards | In Gilbert & Sullivan=92s _Patience_ | February
    | 21-March 1, Sudbury, Massachusetts | http://sudburysavoyards.org |
    +-------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
    617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  4. Phil Holman

    Phil Holman Guest

    "Glenn Ammons" <[email protected]> wrote in message =
    news:[email protected]...
    > I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that
    > it is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
    > string test tells me that the rear triangle is properly centered, and I've used the Park tools to
    > check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
    > judging by eye.
    >=20
    > My theory is that the dropouts are both bent by the same amount, so that the wheel sits
    > cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
    > should check first?
    >=20
    > Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
    > was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
    > triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
    > 4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right
    > side of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in
    > the chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.

    There is a tool for checking and tweaking the allignment of the = dropouts.=20 Most good bike shops
    will have them and will allign your dropouts for a=20 few $$. From previous efforts I don't why
    anyone would want to ruin the=20 ship for a hapeth of tar.

    Phil Holman
     
  5. Phil Holman

    Phil Holman Guest

    "Sheldon Brown" <[email protected]> wrote in message =
    news:[email protected]... Glenn Ammons wrote:

    > I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that
    > it is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
    > string test tells me that the rear triangle is properly centered, and I've used the Park tools to
    > check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
    > judging by eye.
    >=20
    > My theory is that the dropouts are both bent by the same amount, so that the wheel sits
    > cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
    > should check first?
    >=20
    > Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
    > was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
    > triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
    > 4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right
    > side of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in
    > the chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.

    Try putting the wheel in backwards, see if it's still off to the same=20 side of the frame. If it
    isn't, the problem is an improperly dished=20 wheel. If it is, the problem is the frame.

    If the dishing were the problem it would be off between the chain stays = as well.

    Phil Holman
     
  6. Glenn Ammons

    Glenn Ammons Guest

    Sheldon Brown <[email protected]> writes:

    > Try putting the wheel in backwards, see if it's still off to the same side of the frame. If it
    > isn't, the problem is an improperly dished wheel. If it is, the problem is the frame.

    Right on. I swapped the wheel around, and it lines up perfectly. So, it must be a bit of off-center
    wheel and a bit of off-center frame. I'll redish the wheel, and then try the string test more
    carefully. It seems more likely that the rear triangle is off-center than that the rear dropouts are
    both cockeyed in the same direction and by the same amount.

    Thanks. --glenn
     
  7. Glenn Ammons wrote:

    >>I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that
    >>it is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
    >>string test tells me that the rear triangle is properly centered, and I've used the Park tools to
    >>check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
    >>judging by eye.
    >>
    >>My theory is that the dropouts are both bent by the same amount, so that the wheel sits
    >>cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
    >>should check first?
    >>
    >>Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
    >>was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
    >>triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
    >>4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right
    >>side of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in
    >>the chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.

    I suggested:

    > Try putting the wheel in backwards, see if it's still off to the same side of the frame. If it
    > isn't, the problem is an improperly dished wheel. If it is, the problem is the frame.

    Phil Holman wrote:

    > If the dishing were the problem it would be off between the chain stays as well.

    I think this bike has horizontal dropouts, so alignment between the chainstays is variable.

    By the way, glen, don't ignore the possibility of a bent axle, especially if the wheel uses an
    old-fashioned thread-on freewheel.

    Sheldon "Covering The Bases" Brown +--------------------------------------------------+
    | Some of my brother's paintings may be seen at: | http://junila.com |
    +--------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  8. Andrew

    Andrew Guest

    Glenn Ammons <[email protected]> wrote in message news:[email protected]...
    > Sheldon Brown <[email protected]> writes:
    >
    > > Try putting the wheel in backwards, see if it's still off to the same side of the frame. If it
    > > isn't, the problem is an improperly dished wheel. If it is, the problem is the frame.
    >
    > Right on. I swapped the wheel around, and it lines up perfectly. So, it must be a bit of
    > off-center wheel and a bit of off-center frame. I'll redish the wheel, and then try the string
    > test more carefully. It seems more likely that the rear triangle is off-center than that the rear
    > dropouts are both cockeyed in the same direction and by the same amount.

    For the un-educated (ie me) what is the string test?

    Thanks,

    Andrew

    >
    > Thanks. --glenn
     
  9. Glenn Ammons wrote

    >>I'll redish the wheel, and then try the string test more carefully. It seems more likely that the
    >>rear triangle is off-center than that the rear dropouts are both cockeyed in the same direction
    >>and by the same amount.

    andrew Carver asked:

    > For the un-educated (ie me) what is the string test?

    See: http://sheldonbrown.com/harris/frame-spacing.html

    Sheldon "Strings Attached" Brown +-----------------------------------------------+
    | I don't need instructions, I have a hammer. | -- T.W. Wier |
    +-----------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
    617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  10. A Muzi

    A Muzi Guest

    "Glenn Ammons" <[email protected]> wrote in message news:[email protected]...
    > I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that
    > it is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
    > string test tells me that the rear triangle is properly centered, and I've used the Park tools to
    > check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
    > judging by eye.
    >
    > My theory is that the dropouts are both bent by the same amount, so that the wheel sits
    > cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
    > should check first?
    >
    > Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
    > was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
    > triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
    > 4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right
    > side of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in
    > the chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.
    >
    > Thanks. --glenn

    Is it possible to get a consulation with someone familiar with bicycle frame alignment in your
    area? That might keep you from running in the wrong drection. It's not likley to be a twisted
    frame end problem. It could likely be a pair of twisted seatstays, though. You _did_ flip the
    wheel over, right?
    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  11. Jim Adney

    Jim Adney Guest

    On 09 Feb 2003 16:11:02 -0600 Glenn Ammons <[email protected]> wrote:

    >I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that
    >it is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
    >string test tells me that the rear triangle is properly centered, and I've used the Park tools to
    >check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
    >judging by eye.

    Flip the wheel over and try it in there backwards. If the rim is still offset by the same amount and
    to the same side, then the frame is at fault. If the offset is the same, but to the opposite side,
    the rim is not centered on the hub, and if the offset is different, but not simply swapped, then you
    have a combination of problems.

    It is not likely that this is as simple as one forkend being pulled out more than the other.

    -
    -----------------------------------------------
    Jim Adney [email protected] Madison, WI 53711 USA
    -----------------------------------------------
     
  12. On Mon, 10 Feb 2003 16:25:26 -0500, Sheldon Brown wrote:

    > Glenn Ammons wrote
    >
    >>>I'll redish the wheel, and then try the string test more carefully. It seems more likely that the
    >>>rear triangle is off-center than that the rear dropouts are both cockeyed in the same direction
    >>>and by the same amount.
    >
    > andrew Carver asked:
    >
    >> For the un-educated (ie me) what is the string test?
    >
    > See: http://sheldonbrown.com/harris/frame-spacing.html

    404 Not Found

    hmm. Of course, your "not found" page is a lot more helpful than most.

    --

    David L. Johnson

    __o | Become MicroSoft-free forever. Ask me how. _`\(,_ | (_)/ (_) |
     
  13. John Everett

    John Everett Guest

    On Mon, 10 Feb 2003 16:25:26 -0500, Sheldon Brown <[email protected]> wrote:

    >http://sheldonbrown.com/harris/frame-spacing.html

    404 Not Found

    Sorry, the page you are looking for isn't here anymore. If the link that brought you here was on one
    of my pages, please send me an email Make sure to let me know the URL (http://sheldonbrown.com/...)
    of the page that had the bad link, and the location on the page.

    I'd really appreciate it! This site has grown to be very large for one person to maintain!

    It is possible that it has been moved to sheldonbrown.org , instead of sheldonbrown.com , so you
    might want to try changing ".com" to ".org" in the URL while leaving the rest of it alone.

    jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3
     
  14. Mikeyankee

    Mikeyankee Guest

    Here's the current URL. I've done this procedure a couple of times and it works fine. Just be
    patient, measure often, etc.

    http://sheldonbrown.com/frame-spacing.html

    Mike Yankee

    (Address is munged to thwart spammers. To reply, delete everything after "com".)
     
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