Vision R40 Frame is Bent (deformed)

Discussion in 'Recumbent bicycles' started by Grande News, Apr 22, 2006.

  1. Grande News

    Grande News Guest

    this past week my Vision R40 LWB USS took a small detour off road and hit a
    fairly large dip. I went airborne, but did not crash and just kept
    pedaling. I noticed a strange noise coming from the chain near the rear of
    the bike after this bump.

    Today, I finally figured out the source of the noise. The chain is now
    rubbing against the frame when I have the bike in low gear (large rear
    sprocket).

    I have looked at the frame and can't see where it is visibly bent, but I can
    only assume that something changed to cause the rubbing. Has anyone ever
    seen this before?
    Any ideas as to how to determine if and where the frame bent?
    Any way to straighten this if it is bent?

    Thanks for your help. This has been a great bike and hate to retire it
    early (I've had it for 2 months).







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  2. John Kimmel

    John Kimmel Guest

    Grande News wrote:
    > this past week my Vision R40 LWB USS took a small detour off road and hit a
    > fairly large dip. I went airborne, but did not crash and just kept
    > pedaling. I noticed a strange noise coming from the chain near the rear of
    > the bike after this bump.
    >
    > Today, I finally figured out the source of the noise. The chain is now
    > rubbing against the frame when I have the bike in low gear (large rear
    > sprocket).
    >
    > I have looked at the frame and can't see where it is visibly bent, but I can
    > only assume that something changed to cause the rubbing. Has anyone ever
    > seen this before?
    > Any ideas as to how to determine if and where the frame bent?
    > Any way to straighten this if it is bent?
    >
    > Thanks for your help. This has been a great bike and hate to retire it
    > early (I've had it for 2 months).
    >

    Where on the frame is it rubbing?

    If the frame is bent, any reasonably competent bicycle builder can
    straighten it. Since it's a Vision R-40, there's nothing special about
    the steel tubing in it (no heat treat), so if it's cracked, it can be
    re-welded by any competent TIG welder.

    If you take the bike to a frame builder, take the owners manual too, so
    that he can read about how the chain stays on the R-40 are offset to
    allow a symmetrically spoked rear wheel.

    --
    John Kimmel
    [email protected]
    remove x

    "He's dead, Jim."
     
  3. Jeff Wills

    Jeff Wills Guest

    Grande News wrote:
    > Today, I finally figured out the source of the noise. The chain is now
    > rubbing against the frame when I have the bike in low gear (large rear
    > sprocket).
    >
    > I have looked at the frame and can't see where it is visibly bent, but I can
    > only assume that something changed to cause the rubbing. Has anyone ever
    > seen this before?


    I've seen this on a couple different bikes. It's usually caused by the
    routing of the chain being changed somehow. Since your Vision doesn't
    have a power-side idler, I'd guess that the chain's jumped off the
    lower pulley somehow. (You don't say whether the top or the bottom run
    of the chain is rubbing.) I'd put the bike on a workstand and take a
    careful look at things while running through all the gears.

    Beyond that, I *really* doubt that one airborne trip would have bent
    the frame significantly. The Vision frames are pretty tough.

    Jeff
     
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