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Model a speedometer

Discussion in 'The Hokey Ass Message Board' started by bigdd, Dec 28, 2010.

  1. bigdd
    Joined: Dec 9, 2010
    Posts: 5


    Can anyone help? I need to know if you can connect a modern aftermarket speedometer. to a Model A Ford original speedometer gear assembly, mounted in the touque tube?
  2. rmak
    Joined: Jun 18, 2008
    Posts: 134

    from Ohio

    I'm bumping this question up because I can't find the answer either. No one I talk with seems to know, not even the people who sell the gages.
  3. 76cam
    Joined: Sep 30, 2010
    Posts: 644


    I think you got the good question of the day here!!!!!!
  4. i have been thinking about this on my 37 also....dont we just have to mount an electric drive mechanism to the torque tube and it sends an electronic signal to a new speedo?
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  5. jetmek
    Joined: Jan 12, 2006
    Posts: 1,847


    most any speedo will work off the stock ford drive except if its an oddball like a reverse sweep or harley davidson 2:1 ratio just make sure you have the right driven gear tooth count for the ring and pinion ratio and tire size your running. that mite take some trial and error
  6. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,612

    Bruce Lancaster

    To elaborate...Model A's with round speedos ('30-31) use a basically modern cable and the same drive as '32-48.
    Oval speedo A's, 28-30, use a different cable and drive coupling but the drive can be swapped to the late version.
    Bratton's now sells repro drives, including some scarce ratios.
    Threads on speedo drive match many modern cables, those on other end of early Ford cables at speedo don't match so you'll need some 1960's cable housing.
  7. just to add a little bit to this
    the speedo drive has the ratio cast into it so if you have a 3.78 it will say 9-34
  8. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,612

    Bruce Lancaster

    And...they all mesh with the same driven gear on the driveshaft, so the mesh is compensated by a different height for the axis of the driven gear in the little casting! Swapping the gear into a different ratio housing will result in a mesh somewhere between sloppy (or ground into dust) and unusable.

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