Abstract: A collapsible mobile chair assembly comprises a frame having a pair of wheel axles which include rack gearing and are slidably mounted in said frame for axial moveable between an extended operating position and a retracted storage position. The rack gearing of the axles overlap and drivingly engaging a pinion gear provided on the frame, constraining the axles slidingly to move together in opposite directions. Two support plate assemblies are provided on opposing sides of the chair, a rear fork assembly extending from each support plate assembly. A front fork strut and a handle strut are each pivotally attached to each support plate for movement between an extended operational position and a retracted storage position. The front fork and handle struts include gearing formed thereon which mesh so as to constrain struts on respective sides to rotate together between their extended and their retracted positions.