I was talking to Bill a few years ago, when he had removed the portals from Wildfing and he told me that the original pre-portal design had dual wheels on front and rear axles, with the inner wheels being a smaller diameter than the outer wheels. So on the road, the car ran on four wheels, but in deep ruts all eight wheels locked in, liked a V-Belt on a pulley, so that the deeper the rut, the better the traction. Vic-Roads had a lot of trouble comprehending dual wheel front and rear axles and wheels of unmatched diameter though.