The wikipedia article on "Bicycle and motorcycle dynamics" in the "Turning" section http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics#Turning states In order to turn, that is, change their direction of forward travel, bikes must lean to balance the relevant forces: gravitational, inertial, frictional, and ground support. Is this right? I think leaning is done for the rider staying on the bike. (balancing the moment of the friction and the moment of the normal force about the C.G) and not for initiating the turn. comments?