Now, if you mean what gear ratio you have, you can determine that also. If you have a posi unit, of course, it's easy. With the rear wheels off the ground, count how many times the driveshaft turns in order to turn the tires one revolution. Just over 3 turns is a 3.08 ratio, 3 1/2 turns is a 3.55 ratio. just under 4 turns is a 3.90, and so on.

If you have a one wheeler, I'd pull the cover and look at the numbers. There'll be 2 numbers, close together, on the ring gear. The smaller number is the number of teeth on the pinion gear. The larger number is the number of teeth on the ring gear. Divide the small number into the large number and you have the gear ratio. The numbers 10 41 would be a 4.10 ratio.