Manual wheelchairs are those that require human power to move them. Many manual wheelchairs can be folded for storage or placement into a vehicle, although modern wheelchairs are just as likely to be rigid framed.
Manual or self-propelled wheelchairs are propelled by the occupant, usually by turning the large rear wheels, from 20-24 inches (51–61 cm)in average diameter, and resembling bicycle wheels. The user moves the chair by pushing on the handrims, which are made of circular tubing attached to the outside of the large wheels. The handrims have a diameter that is slightly less than that of the rear wheels. Skilled users can control speed and turning and often learn to balance the chair on its rear wheels — do a wheelie. The wheelie is not just for show — a rider who can control the chair in this manner can climb and descend curbs and move over small obstacles.