The first time I ever built one of these bikes with the big tires I spent two weeks just changing gears to get it right , I always try to find the smallest sprocket for the crank and then the biggest gear for the first side of the jack shaft , then a smaller gear for the second side of the shaft and always the biggest gear I can find for the wheel , I tried putting on a multi speed gear set on the wheel but the chain is so short the chain gets bound up on the jack shaft gear when you change gears , the way I do the gearing now works pretty good , I am no where close to being in shape and I can put 10 miles on it with it killing me , there kinda like peddling a 29" tire bicycle because the tire is a 29x11x15 and I put about 40 psi in it so the tire crowns pretty good so your only riding on about 3" of the tire , and ya the bikes done weigh about 75 lbs , there not light weights but a whole lot of fun to ride and they turn heads where ever we go riding