Auxilliary support systemsAuxiliary supported run-flat tires do not rely on the tire itself to maintain its integrity when it loses air pressure. Instead, arched blocks or rings are attached to the wheel to provide a surface to drive on. The attachment gives the best chance of being able to get away after being shot, as there is a solid connection between the wheel and the road. Also, even if the tire is shredded, the auxiliary should still be fully intact, as it is a separate unit.The main drawback to auxiliary supported run-flat tires is that they are heavier than self-sealing or self-supporting tires. The result is a harsher ride, poorer fuel economy, and longer braking distances. On the other hand, auxiliary supported tires are more stable on the road than self-supporting tires, and the wheels won't cut into the tire or road for as long as the inner rings maintain their structural integrity.