Count the number of teeth on the pinion gear and count the number of teeth on the ring gear. Divide the ring gear teeth number by the number of teeth on the pinion. The result is your gear ratio.
|41 teeth on ring gear||41 teeth on ring gear||40 teeth on ring gear|
|10 teeth on pinion||12 teeth on pinion||13 teeth on pinion|
|41/10 = 4.10||41/12 = 3.42||40/13 = 3.08|
Note: you may need to round off the number.