Thanks rich, stock on the 250F is 13/52. I can run almost everything in 3rd gear except for steep hills, even tight single track turns from a slow almost stop. When racing I stay between 2nd and 3rd and when it opens up, 4th. This way I am in no fear of hitting neutral by accident. I just picked up a Moose 13 tooth for under $20 and it is heavier than the stock one that came off. I would think you would want to gear the bike where you can run 3rd most of the time, 2nd on hill climbs, and 4th, 5th when it opens up. What gears do most of you run in on the 450? Remember, 1 tooth on the front equals 3 to 4 on the back. What gears do you find yourself in most of the time now?