A swing arm assembly for a foldable wheelchair consisting of a camber tube and adapters is disclosed. The adapters mount to the frame of the wheelchair and receive the ends of the camber tube. One end of the camber tube is pinned into an adapter such that it pivots. The other end is pinned in an adapter using a quick release pin. The camber tube improves the stability of the foldable wheelchair. When desired to fold the wheelchair, the quick release pin is removed and the camber tube is rotated approximately 90 degrees, thereby allowing the wheelchair to fold. The adapters may be mounted to the wheelchair frame or to stub axles if used. The swing arm assembly adds substantial stiffness and stability to a folding wheelchair.