A run-flat support ring, which is a component mounted upon a rim inside a tire to extend the distance the tire may travel at reduced or zero inflation pressure, is provided having an internal fin design that improves the rolling resistance of the support ring without sacrificing the overall load bearing and handling characteristics. Certain embodiments may also include one or more features that improve the process of mounting the support ring onto a rim and better tolerate variations, within manufacturing tolerances, in the respective diameters of the rim and the support ring.