Fixed gear chainline

Discussion in 'Cycling Equipment' started by Jai Ma, Sep 7, 2004.

  1. Jai Ma

    Jai Ma Guest

    I've set up the cranks and bottom bracket that I'm going to use for my fixed
    gear project (Thanks to Sheldon Brown for his excellent articles). The
    chainring chainline measures 43.5 mm. So with my 124 mm dropout spacing (Is
    that probable? It was a six speed. I've measured it over and over) I
    calculate the cog should be 18.5 mm from the bolt that goes against the
    inner side of the dropout. So far so good, I respaced the hub along the
    axle to that and visually it looks perfect.

    I have two issues. After I redish the wheel I will end up with a slight
    negative dish. Aside from the fact that I think I will have to switch the
    spokes from left to right, it doesn't seem like a problem to me, but I have
    no experience and wonder if this seems reasonable?

    The other issue is that in the future I would like to put a flip/flop hub on
    it. It seems to me that would mean I will be forced to make the crank and
    bb chainline conform to the hub instead of the other way around as I'm
    doing. Could I get a flip/flop hub to have the right rear chainline on a
    bike with 124 mm dropout spacing and a 43.5 mm chainline up front?
     
    Tags:


  2. John Dacey

    John Dacey Guest

    "Non si male nunc et olim sic erit." - Quintus Horatius Flaccus
    On Tue, 7 Sep 2004 17:18:39 -0700, "Jai Ma" wrote:

    <snip>

    >I have two issues. After I redish the wheel I will end up with a slight
    >negative dish. Aside from the fact that I think I will have to switch the
    >spokes from left to right, it doesn't seem like a problem to me, but I have
    >no experience and wonder if this seems reasonable?


    Don't move the spokes from their current orientation in the hubshell.
    If the length(s) aren't appropriate to redish the wheel with the ones
    fitted now, either rebuild it with new spokes or (better yet)
    accelerate you plans to acquire the new wheel that you mention below.

    >The other issue is that in the future I would like to put a flip/flop hub on
    >it. It seems to me that would mean I will be forced to make the crank and
    >bb chainline conform to the hub instead of the other way around as I'm
    >doing. Could I get a flip/flop hub to have the right rear chainline on a
    >bike with 124 mm dropout spacing and a 43.5 mm chainline up front?


    Assuming the chainline calculations you made (in the section I
    snipped) for your crank are accurate, you should be able to simply fit
    a 1.5 mm spacer (plus or minus a smidgeon, depending on the exact
    components used) between the sprockets and the sprocket seats on the
    shell of most track hubs that conform to the common track chainline
    standard. Many track hubs spaced by default at 120 mm will allow you
    to add a 2 mm spacer between each cone and locknut to symmetrically
    space the hub to 124 OLN.

    There's some chainline info for track equipment at
    http://www.businesscycles.com/tr-refspec.htm#chainline


    -------------------------------
    John Dacey
    Business Cycles, Miami, Florida
    http://www.businesscycles.com
    Since 1983
    Our catalog of track equipment: online since 1996
    -------------------------------
     
Loading...
Loading...