Abstract: A supporting frame for a wheelchair seat includes an axle tube mounting rear wheels, tubular side members pivotally mounted on the axis tube and carrying front castor wheels, a front transverse tube of rectangular cross-section connected to the side members by pin connections allowing limited vertical movement of the side members relative to each other, and a T-shaped member, the lower end of the upright limb thereof being connected to the middle of the front tube to allow turning of the T-shaped member about a middle longitudinal axis, and the horizontal limb thereof bearing the front of the wheelchair seat.