I just swaped the gears in the 440 truck from 3.91 to a 3.23,now the speedo is off a little.

I had a 38 tooth pinion in it with the 3.91 gear running a 29x15x15 M/T sportsman SR radial. seemd about right but never really checked it.

now with the 3.23 gear i swaped in a 32 tooth pinion. looking at the speedo pinion chart and a test drive i think the speedo is a little slow still.

did I get the math correct with the 32 tooth or would it need a 29 tooth maybe???

my 29 tire stands 28" tal by the tape measure.. now I am confused with the math

Miley,, Turn yor smart phone on to the GPA app. Drive down the road and compare the GPS MPH to the truck MPH. Knowing what gear you know have you can figure whether you need more teeth of less on the speedo gear.

If the tires are actually 28" in diameter (check the actual rollout to be sure) you need a 30 tooth pinion.

thanks John.

I tried a 32 and the math is saying 30. just my luck, I have a 27,29,32,35,38,40 tooth pinions.

I think I will look for a 30 and try the 29. if that is close enuff and keeps me under radar on the street that works for me.

I think I will swap in another cluster on my stepside and hook the speedo up in it while I am at it. I come up with a 25 tooth for 235/75/15 & 2.76 gear.

again,just my luck. no 25 or 30 tooth in my collection of pinions.

if I stick the 3.55 gear 235/75/15 in the stepside that will adjust the gear ratio to match the 32 tooth pinion I do have. now thats the hard way to correct the speedo.

25 will need a different adapter, the 3-position adapter only covers the 26-45 range.

thanks again John.

I will have to scratch one up along with the 25 gear.