tire size also plays into gearing a good bit. as you can see from above posts, a lot of guys run the 14/40 gears (so do I) but they might run a 18 or 20 inch tire. I personally use the 20 inch tire and that with the 14/40 gears is a pretty good all around gear ratio. generally 1 tooth in the front= 3 teeth in the back. youll have to play around a little to find what works best for you.