My New Speedometer/Odometer Correction Box

A few weeks ago I posted a note about a mechanical odometer that I had recently acquired.  That odometer, a Kanto Seiki, was a mechanical odometer that was available in the early 1970s as a substitute for the Halda Tripmaster.  A problem with the Kanto Seiki odometer is that it can not be calibrated itself.  The correction or calibration has to be done externally to the odometer.

Kanto Seiki Odometer

I have this problem to a smaller extent with my other mechanical odometers such as the Halda Speedpilot and the Hemo Trip Taeller.  These odometers are calibrated by turning screws which is a procedure that not as well defined or precise.

The Hemo Trip Taeller Odometer

This past week I acquired a speedometer/odometer correction box which will go along way to resolving the calibration problems with these odometers.

Speedometer/Odometer Correction Box

This device allows for the installation of internal gears that will adjust the rotation of the speedometer/odometer cable.

 Inside View of the Speedometer/Odometer Correction Box

The device comes with a set of gears that can be installed inside the box that will change the output cable rotation speed.

Gears for the Speedometer/Odometer Correction Box

The device comes with a table which shows which gears to install based on the factor.

Calibration Table

This speedometer/odometer correction box was originally sold by a rally equipment business, “Competition Limited” in Dearbon, Michigan.  Competition Unlimited prepared the calibration table for the correction box.  Competition Limited was one of the major rally equipment businesses in the 1970s and 1980s.  It was run a well-known and successful SCCA Pro-Rally competitor, Gene Henderson.

Over the upcoming months I will be using this device to get comfortable with its usage.  I am interested in how long it takes to adjust the speedometer/odometer correction box.  In many of today’s rallies, the time allowed for odometer calibration is based on the time it takes to calibrate an electronic odometer – not a mechanical odometer.  Perhaps in rallies where mechanical odometers are anticipated, an odometer calibration run could be run prior to the start of the timed portion of the rally.  This would be more competitor friendly.  This approach was used in the classic rally in Germany that I recently competed in, the Baden Classic.  At that rally, a calibration run was available for all competitiors the day before the formal rally, therefore all cars could have a fully calibrated odometer prior to the start of the timed portion of the rally.

I will post at a later date on my tests for this device, especially when used along with the Kanto Seiki odometer.


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7 Responses to My New Speedometer/Odometer Correction Box

  1. Hi Steve
    I used the plastic correction gear box back in the 60’s and 70’s until I bought my first Zeron 660. The gear box was a bit noise. I used some medium grease to help the gears rotate together.
    Gears will have different pitch diameters based on the number of teeth on the gear. In this unit you have two centerlines for the shafts which should limit your gear selection. They solved this by making the gears have a loose fit which results in noise and friction (heat) which is why we lubricated the gears after the mileage check. If you look at the correction table you will find the greated selection of gears in a very small range. We use to try and set the base mileage so we could fall into the small range of gear selections . It will take some time to become an “expert” but it should be fun. I still have the Xeron 660 and several of these gear box units in my collection of old stuff.
    I reall enjoy your article and they bring back a lot of memories from days in the Finger Lakes.
    Bill Laitenberger
    Cornville Arizona

    • Hi Bill,
      Thanks for the information about these units. Further to your comments about the odometer correction box, I got the following message from Mike Mazoway of the Syracuse area about a week ago regarding his experience with the the odometer correction box:

      I have had one of those adjustable gearboxes for more years than I can count. It was a LOT cheaper than buying all of the halda gearsets. It works best with short cables and tends to be noisy. Put is as close to the instruments as possible. Long cables in or out of it tend to make the operation very jerky due to cable windup. Do NOT oil or grease the gears or shafts as it will actually create more friction. I used a little graphite powder on the shafts for lube and it seemed to help. Make sure that the case is fully closed and the pins are fully inserted. I put a piece of tape around the case to make sure it did not separate (I had it come apart on me once). Overall I thought it was a good investment at $15 for a used set. I think I got it in the late 70’s or early 80’s. I believe Gene Henderson originally sold the set for about $30 or $35.

      I have not used mine yet, but I plan on doing so soon, just to test it out.


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  3. Kathryn says:

    Would you please tell me where, or if, I can get one of these?

    • Hi Kathryn,
      These devices are not particularly common. I am not aware of any place where these can be purchased new. I bought my speedometer correction box on eBay, but I have not seen another one offered for sale since. These units were commonly used in the days when Halda odometers and stock car odometers were used in rallying. The strategy to find one would be to contact older rallyists in your area or retired rally people who might have such a device in their basement somewhere. I know one fellow who I think has one, but I’m not sure if he would sell it and I know another source who possibly has one. Send me a private email at and I’ll pass along contact info about these potential sources.
      We could add a notice on my Rally Navigation equipment page that you are interested in buying such a unit, if everything else fails.
      Steve McKelvie

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