I am running 40-16 on my Ogre. I tried 44-16, 42-16, and 38-16 before I settled on this. This puts me in gear 9-10 for most of my relatively level-ground riding which is where I am convinced it ought to be. I believe that your normal-flat running get should be 75% of the top. You always need smaller ones for wind/hills. While you also need taller gears for wind-at-your back and down hills, you spend more time going up. The Troll has smaller wheels, so smaller gears are probably in order.