The math is correct, but the actual gears do not interchange. It only works with everything that those gears are available for the transmission you are using. You can not find all the gears suggested by that program for every transmission.
For instance my SM465 would need a 15 tooth drive with a 41 tooth driven with 6.13 rear gears and 33 inch tires, but unfortunately there is no 15 tooth drive gear or 45 tooth driven available for the SM465. However a 6 tooth drive with an 18 tooth driven are available.
If I had a 3.08 rear with a 29 inch tire, I would need a 17 and 36, unfortunately on my transmission I would have to settle for 8 and 17 speedometer gears.
Does that make sense?
