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How to fix a spedometer

Discussion in '80-Series Tech' started by Mr.Bryan, Oct 9, 2003.

  1. Mr.Bryan

    Mr.Bryan

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    Ok here is the problem. The spedometer is slow by 5mph. It shows 45 i'm doing 50. Is there an adjustment or anyway to fix it myself or should I bring it into a shop and have them do it? Also, I have 305/70 16 tires. I dont think the tires would make it off by that much though. Am I wrong? ???

    Thanks for any help,

    Bryan
     
  2. landtank

    landtank SILVER Star

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    a new speedo gear should fix you right up. Sleeoffroad.com has them. As it turns out so do I but went with 35" instead which requires a freq. modulator.
     
  3. sjcruiser

    sjcruiser

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    Bryan,

    IIRC, you're running on ~33in; whereas stocks are ~31.2in - should make some difference in the meter, but 45 vs 50mps seems a bit high.

    Frank.
     
  4. MTNRAT

    MTNRAT

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    If you want your speedo bang on, get the Truespeed speedometer calibrator. Then you are also ready for when you go to 4.88s and 35s. :D. You can order one from sleeoffroad.com as well.
    Sean
     
  5. Beowulf

    Beowulf

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    >> Am I wrong? <<

    Yes, you are wrong. The tyres will affect the speedo and odo by the same percentage that you increased the circumference (approx 6% IIRC)

    Get the xfer case gear from Christo and your problem is solved. I'm running 285/75's right now and the speedo is close to perfect based on the GPS (tyres at 40psi)

    The TruSpeed is the way to go if you plan to swap trail/street tyres and/or if you are going over 33" tyres.

    -B-
     
  6. Mr.Bryan

    Mr.Bryan

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    >>Yes, you are wrong.<< Ahhh honesty at its best. :D Thanks very much guys. My next tire is a 35" so looks like truspeed it is.

    -Bryan
     
  7. sleeoffroad

    sleeoffroad Supporting Vendor

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  8. landtank

    landtank SILVER Star

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    When I installed my truespeed I had velcroed it to the top of the heater core. Christo's glovebox install is real convienent if you need to switch between sizes a lot but even tuck away behind the glove box isn't too bad, it only takes 2 screws to get to and leaves the glove box open for more of my wifes toiletries :-[
     
  9. Mr.Bryan

    Mr.Bryan

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    -Christo, dont worry you'll be gettin a call from me in a few weeks. I need $ first.

    -Landtank, glove box thing is perfect (checked out Christo's site) I dont have anything but the owners manual in there anyways so... works for me.

    -Bryan
     
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