A vehicle wheel positioning and steering apparatus particularly useful for aerial work platforms comprises a support chassis and chassis support legs pivotally connected to the chassis. Steerable wheel assemblies are operably connected at ends of the support legs and powered actuators are operably connected to the chassis and legs for pivotally moving the legs and wheel assemblies relative to the chassis between transport and working positions. Variable length linear wheel steering actuators comprise one link of four bar parallelogram steering linkages between the chassis and wheel assemblies and the support legs each comprise second bars of the four bar parallelogram steering linkages.