Abstract: A hand operated wheel-chair with a pair of main wheels rigidly connected with the frame-work of the chair, at least one of which is either motor or hand operated and at least one castor wheel being pivotally connected with the frame-work of the chair and at least one support wheel being rigidly connected with the frame-work. At least one castor wheel and support wheel are positioned on each side of a line extending between the support points of the main wheels and at a level above the ground surface to permit either the castor or the support wheels to be in contact with the ground surface depending on whether the vertical through the center of gravity is located on one or the other side of said line between the support points of the main wheels.