@ A run-flat pneumatic tire 10 has a compression element 36 of annular structure on an inside surface 38 of the crown 22 thereof, which compression element 36 is stabilized by a multiplicity of closely spaced spoke-like radial elements 32 in the tire sidewalls 24 such that de-pressurized operation of the tire without damage is possible. The compression element 36 is a helix with closely spaced coils wound from a rod of a cross-sectional shape selected from various solid and tubular configurations. Round, square, and rectangular coil cross-sectional configurations are disclosed, as are interlocking convex/concave and tongue/groove arrangements. The helical compression element 36 is installed in the tire 10 by winding up the helix to reduce its diameter such that it can pass through bead portions 26 of the tire, or by introducing one end of an end coil of the helix over one of the bead portions 26 into the interior of the tire 10 and effecting relative rotation to feed the helix into the tire. The compression element 36 can be bonded in place and can also be preloaded by various means.