A knee walker includes a steering column rotatably attached to a forward portion of a frame, wherein the steering column includes a steering pulley rotatable about a vertically disposed axis of rotation. Two wheel assemblies are rotatably carried by the frame and have a pulley for rotating each assembly about a vertical axis. The axis of rotation of each wheel assembly is offset aft the steering column axis. A belt links rotation of the steering column to rotation of the wheel assemblies and in combination with the offset causes the belt to extend around at least half a circumference of each pulley for enhancing frictional contact. A shield guards each pulley. Mating alignment disks for aligning each assembly are provided to permit wheel alignment without affecting the belt tension. A third wheel assembly optionally extends from the column.