Banded tire load enhancement system

A self-energized tire load enhancement means for a banded radial run-flat tire system comprising in combination:

• a wheel having a hub, a drop-center rim, and a wheel body joining said hub to said rim, said hub accommodating an axle for mounting said wheel on a vehicle;
• a resilient, pneumatic banded radial run-flat tire having a casing with a crown, sidewalls extending from said crown on either side to annular bead portions mounting said tire in a sealed relationship on said wheel rim, a resilient annular band element in said tire crown, said band element being stabilized by a multiplicity of closely-spaced substantially spoke-like radial reinforcing elements in said tire sidewalls;
• tire inflation means in said wheel rim for the inflation of said tire;
• and
• a torodial resilient expandable inner tube located within said casing of said tire, said tube being diametrically undersized with respect to the size of the inner tube normally fitted on said wheel, tube inflation means in said wheel rim for the inflation of said tube, the inflation pressure of said tube being less than a quarter of the inflation pressure of said tire, the tire being inflated to a pressure that in normal operation compresses said tube into the annular region of said tire adjacent said rim substantially clear of the interior walls of said casing whereby, when said tire loses inflation pressure, the release of said tire pressure acting on said tube causes it to expand outwardly against said sidewalls to impart a curvature to the reinforcing elements therein at least about 45.degree. on either side of the centerline of the footprint in contact with the surface to thereby enhance the fatigue characteristics of said band and the load capacity of said deflated tire.