Good question, because the solution can be used on any snowmobile for many different applications/mods. Count the number of drive lugs on your drive sprocket, then measure the center to center distance between the drive lugs on the TRACK, then just multiply those numbers to get the circumference, then divide by 3.1415 to get the diameter. So a 9 tooth sprocket with 2.500 inch TRACK pitch gives you 22.5 inch circumference, divide by 3.1415, gives you 7.162 diameter.
