The Stovebolt Site Forums The Shop Area General Truck Talk Speedometer Correction

Anyone have a good source for speedometer correction adaptor gears??

http://www.speedometershop.com/rep-pag.htm

I averaged odometer readings from 10 x 10 miles measured on an interstate at 60 mph. They made an adapter that has worked on both a stock 3-speed and a stock 4-speed - to within 1% accuracy.

What kind of tranny are you using? How far is it off? Reading fast or slow?

Are you sure you need an adapter? I corrected mine (T5) with a simple driven gear swap - just cost a few bucks.

I've had good luck with the guys at www.thegearbox.org

Sure the others are fine, but a guy that rebuilds instrument clusters suggested this one:

http://www.transmissioncenter.net/speedometer_calibration_______va.htm

Thanks for the help guys.

I’m running the 41’s stock 4 speed, but have changed the ring and pinion from 4.56 to 3.38 I also have slightly smaller diameter tires. Over all I need to speed the speedometer up by 23%

I think that my adjustment was about 18% (3.55 rear conversion and ~31" diameter radial tires).

Finding a correct combination of drive/driven speedometer gears for an original 1941 4-speed transmission seems quite unlikely.

If the company listed by The Green Farmer can provide an adapter, its prices look to be very good (#54RA2 might have correct cable fittings). Give them a call. Ask if they can make an adapter for a specific % correction.