727 speedometer gear

340mopar said

When I do the calculating I show you need a 35 tooth (orange) gear. I used a measurement of 26.57" for your 245/60-15 tire. Plus it is best to have your speedometer to read a little fast than a little slow for obvious reasons. When you find one I would be interested in your 29 tooth gear. It is the one I need for my '74 D200.


Chuck

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I have been having the same issue with my speedo showing faster than my GPS. I read your post about measuring the tire size as I'm running the same tire as the OP 245/60/15's. I'm running 32psi in the tires and I took a measurement to the center of the wheel X2 and I come up with 25". So the chart shows I should run a 40 gear which I had in there and she read 5 mph fast, so should I go to a 42 tooth gear ? I went to a 38 as someone suggested and now I'm 10 mph fast on the speedometer to my GPS.