I rode the bike with the 6" drive wheel and it isn't the best bike I have but it is a good little bike. The wheel has no tread so it is a bike with less traction. Also the smaller wheel runs faster but with less torgue. In other words it is find on more or less flat surfaces and small inclines but on the long steep inclines prepare to workout.

Also it goes through some power. With the amount of slip because of the smooth tread and small size of the drive wheel, I'm not sure that the 350 watt motor would do as well. I might give that a try someday.