PURPOSE: To enable safe travel of comparatively long distance even at the time of the internal pressure of a pneumatic tire being lowered by a puncture or the like by using compound resin material of 7000-120000kg/cm2 in the modulus of flexural elasticity, 10-25kg/cm2 in Isod impact value (notched) and 220°C (18.5kg/cm2) or higher in thermal deformation temperature.

CONSTITUTION: An inner ring assembled body 10 supports a pneumatic tire 12 from the inside so as to impede its collapse and thereby to enable the travel of the pneumatic tire 12 in the internal pressure lowered state. The inner ring assembled body 10 is also rotated sliding on the well part 14A of a rim 14 by the force provided from the pneumatic tire 12 so as to prevent rubbing between the crown part inner surface 18A of the pneumatic tire 12 and the radial outer end of the inner ring. At this time, a great deal of frictional heat is generated at the contact face of the inner ring assembled body 10 with the well part 14A of the rim 14, but the inner ring assembled body 10 stands this frictional heat because of being formed of compound resin material of 7000-120000kg/cm2 in the modulus of flexural elasticity, 10-25kg/cm2 in Izod deformation temperature.