all of which have a front wheel that leans and a pair of rear wheels that do not, and the Piaggio MP3, which has two front wheels and a single rear wheel, all of which lean. The Yamaha Niken is also a tilting three wheeler but has smaller track width such that it is considered a motorcycle by some authorities. See also Motorcycling Outline of motorcycles and motorcycling List of motorcycle manufacturers List of scooter manufacturers List of motorized trikes Notes