Wheel Size And Drivetrain Changes. How To Correct Harley-Davidson Speedometer Reading.

Naumann32The downside to making changes in gearing or wheel sizes is that it throws off the speedometer reading. If you’ve got a pre–’96 Harley, or custom bike using a mechanical speedometer, you have to change either transmission speedometer drive gear, or front speedometer drive unit, or sometimes even have to change out the speedometer to a different ratio to correct the speedometer reading. Even then, readings may still be only within a couple of mph of being accurate.

speedoThat’s where bikes equipped with electronic speedometers are really cool. Either stock or custom bikes can be set up with a ’96 and up style electronic speedometer, and in a way that allows changing the speedometer reading without the trouble of swapping out parts to get a correct reading. The 1996–up OEM electronic speedometer itself isn’t adjustable.

To realize the full potential of the electronic speedometer, S&S designed a nifty little Electronic Speedo Calibrator Unit that plugs directly into the existing wiring and requires no tools or test equipment to use. It is makes accurately calibrating 1996–up OEM electronic speedometers a snap! It fits all Big Twin and Sportster® models originally equipped with electronic speedometers. It’s also great for custom builders using a ’96 and up OEM style speedometer and transmission.

2TallWheelThe calibrator unit allows builders freedom to create without concern for speedometer accuracy, because the unit can be adjusted so that the speedometer reads accurately with whatever combination of gearing and tire sizes has been chosen. In most cases, it can be set so that the speedometer is accurate to within .5 percent of actual speed. What does .5% mean in mph? For simplicity sake, let’s use 100mph as an example. 1%t of a 100 mph is 1 mph, and half of that one percent (.5) is one half mph. So, recalibrating your speedometer to read within one half mph of actual speed is possible. It is important to note, though, that the calibrator is designed to work with OEM components, and may not be compatible with aftermarket speedometers or RevTech transmissions.

The S&S Speedometer Calibrator Unit allows the rider to correct Harley-Davidson electronic speedometers easily and without special tools or expensive test equipment. Installation is simply a matter of unplugging the connection between the transmission sensor and speedometer and plugging the two connectors into the S&S calibrator. The calibrator can then be used to correct the difference between actual and indicated speeds and mileage. Fits all Harley-Davidson 2006 and earlier big twin and Sportster® models equipped with O.E.M. electronic speedometer, except 2006 Dyna® models.

8 Responses to “Wheel Size And Drivetrain Changes. How To Correct Harley-Davidson Speedometer Reading.”

  1. 1 zipper Jun 17th, 2015 at 8:51 am

    I use a bicycle gps on my custom bikes that have no way to install a speedo. The units are very small and install with a handlebar bracket making it very easy to move to different vehicles. The gps also has a lot more information than you will ever need. No wires, maintenance, or installation other than one wire tie. I use the gps on my HD’s that do have speedos for the other info it provides and the speeds are very close except the gps reads out to the tenth of one mph. An easy fix for custom bike builders. ..Z

  2. 2 G. Messera Jun 17th, 2015 at 9:40 am

    You know that you go too fast when police stops you.

  3. 3 SIGFREED Jun 17th, 2015 at 10:46 am

    G. Messera – he, he, he. They will even provide you with a written confirmation, of your most recent principle velocity, but naturally such proceeding are often accompanied by a capital investment in an appropriate government bond.

  4. 4 Zenaldo Jun 17th, 2015 at 12:16 pm

    sounds like a warranty extender to me….

  5. 5 Ilene Jun 17th, 2015 at 1:58 pm

    I have a Motogadget that is adjustable on my 2001, but if I didn’t, this would be handy. S&S always makes good products.

  6. 6 birddoggie Jun 17th, 2015 at 5:26 pm

    My Garlic Indian has a feature on its speedo that let’s you adjust it to a gnat’s ass. Works great. HD should look into son thrilled g lime that. And yea, S&S products are da bomb…

  7. 7 birddoggie Jun 17th, 2015 at 5:28 pm

    My Garlic Indian has a feature on its speedo that let’s you adjust it to a gnat’s ass. Works perfect. And yea, S&S products are da bomb…

  8. 8 Doc Robinson Jun 18th, 2015 at 7:07 am

    I had one of these fitted to my 1970 Shovelhead that is running a Baker Drivetrain 6-into-4 and an electronic speedo from an Evo. Using the S&S calibre unit my local bike shop, Adelaide Bike Works, used it to calibrate the speedo, which totally agreed with the GPS. On the first part of my ride from the bottom of Australia to the Top End, having an accurate speedo (odometer) helped with fuel planning as I rode through the outback. My ride is to raise awareness and funding for depression and some readers of Cyril’s Blog might like to check out. It honours a young Australian doctor and a young American nurse. Please go to http://www.southerncrossridefordepression.com

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Cyril Huze