A pneumatic insert for a pneumatic tire comprises a generally toroidal shaped hollow member having a pair of annular insert beads with sidewalls extending therefrom joined to an insert crown portion. An annular flap portion is joined to the outer surface of each insert sidewall at the bead area and extends beyond each bead a predetermined amount.The pneumatic insert is disposed in a standard tire and mounted on standard rim. The insert flaps are tucked between the respective insert beads and the bead support surface of the rim to provide a leak-tight seal. When the insert is inflated the insert beads push the respective tire beads against the rim flange. In one embodiment the tire is inflated through an air passage member disposed between the tire and insert beads. In another embodiment the tire is inflated directly through the tire sidewall with a hypodermic needle. The insert inflation chamber and the tire inflation chamber do not communicate and can be inflated to different pressure levels.Other embodiments of the pneumatic insert include fabric reinforcements and/or protective caps.