High Quality Content by WIKIPEDIA articles! Small wheel bicycles are adult bicycles which have wheels of 20 inch (51 cm) nominal diameter or less, which is smaller than the 26" size common on many full-size adult bikes, especially mountain bikes. While many folding bicycles are small wheel bicycles, not all small wheel bicycles can fold. Some small wheel bicycles neither fold nor separate, such as the Moulton, which comes in both fixed frame and separable frame versions. While BMX bikes also have 20" wheels, they are not normally categorised as 'small wheel bikes'. For general information on small wheel folding bikes, please refer to the Folding bicycle article. For specific manufacturers, follow the categories links. An early proponent of small-wheeled adult bicycles was Alex Moulton who pioneered the field with his F-framed Moulton Bicycle in 1962. His original small-wheeled design notably featured full suspension. Raleigh introduced the RSW-16 as a direct competitor, but it lacked the suspension of the Moulton, and compensated for this by using very wide 2-inch "balloon" tyres.