A wheelchair rear wheel support assembly and a detachable arm assembly is described. The rear wheel support assembly is adjustable by finite adjustment both in the horizontal and vertical planes whereby to adjust the position of the rear wheels at a center of gravity to suit a user person to optimize the efforts of propulsion of the wheelchair by the user and thereby significantly increasing its quality of life. The detachable armrest is easily adjustable in height and can be pivoted away from its position of use by simple hand-operating levers easily accessible to the user person. It can also be easily removed with little effort.