Abstract: A pneumatic run-flat insert for a pneumatic tire is provided with circumferential sections having different radii. During vehicle operation in a run-flat condition the different insert radii cause a vibratory disturbance at a wheel axle that alerts the driver of the existence of a run-flat condition or an abnormally low-pressure condition in the tire. During normal driving conditions there is clearance between the insert and the tire liner and no warning vibrations will occur in the wheel axle.In various embodiments of the invention the different insert radii correspond to two or more ply sections in an insert ply having different cord angles. A relatively high cord angle ply section will furnish a relatively larger radius than the ply section with a relatively low cord angle.

Abstract: 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. Each insert bead has a foot portion with a projecting elastomeric formation at the bead heel to furnish an inner bead diameter at the heel that is less than the inner bead diameter at the toe.In at least one embodiment of the invention the bead heel projection is of triangular shape with a vertex of the triangle defining the first inner bead diameter.In another embodiment of the invention the projecting elastomeric formation extends axially away from the bead heel in a direction substantially parallel to the bead foot.

Abstract: 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.