I ran the numbers through and here's what I get.

I got 0.625:1 pulley ratio.

input shaft to bevel gear is 2.538:1

1.692:1 output to axle ratio.

Total reduction ratio not including the shifted gears is 2.683935:1

1st gear is 2.4375:1

2nd gear is 1.619:1

3rd gear is 1.2:1

Total drive ratios in each gear will be:

1st is 6.542:1

2nd is 4.345:1

3rd is 3.221:1

The ratios sound right. But plugging them in to get MPH using what stvn_VA posted, I still get some seemingly odd/large numbers.

41.544mph 1st gear.

62.55mph 2nd gear.

84.378mph 3rd gear.

As a machinist and CNC Programmer, I have brainwashed myself into enjoying doing math stuff like this. Probably because of what it's getting used for....

Your numbers are right!!!!!

I think 32.48 MPH is kinda fast for a 10:1 ratio as in the example. Check your numbers again on the tranny to axle ratio, should be around 1.7

For the example given the 32.48mph is right!