@ A run-flat pneumatic radial tire is equipped with a prestressed helical coil (36) which is positioned inside the tire crown (22) radially inwardly of the tread (20) thereof. The coil is wound to approximately 50 percent of its free diameter to prestress it and the outer surface has a resin-impregnated tape (60) applied thereto. The tape serves to hold the coil in a predetermined condition while the taped coil is cured (62). The taped coil can be co-cured in situ with the tire or prepared in advance of tire fabrication.