A gauging system is adapted for use with a crop harvesting header of the type having a pair of wing frame portions connected to a center frame portion by a balancing linkage and which is operable in a first mode of operation by engagement of a skid plate of each wing frame potion along the ground. In one embodiment of the invention, the gauging system includes i) outer gauge wheels supporting the outer ends of the wing frame portions such that the skid plate is at a controlled distance from the ground and ii) inner gauge wheels proximate the center frame portion for supporting the inner ends of the wing frame portions such that the skid plate is at a controlled distance from the ground according to a second mode of operation of the header.