Patent ID: 7448422
Filing Date: 2008-11-11
Classification: B60C,Y10T

Abstract:
1. A pneumatic run-flat tire, the tire comprising a radial carcass reinforcement ply, a belt structure, a pair of opposing bead regions, each bead region has a bead toe and a bead heel wherein the bead toe is axially outward and radially inward of the bead heel, and a sidewall radially outward of each bead region, each bead region having a bead wire wherein a cross-sectional width of the sidewall from radially outward of the bead region to the ends of the belt structure being substantially constant, so that the cross-sectional width of the sidewall varies by no more than 30% of the smallest cross-sectional width, the substantially constant cross-sectional width begins at a radial height of 15 to 25% of the radial height of the tire as measured from the bead base line and no more than 5% of the radial height of the tire from the radially outer surface of the bead wire; a first rubber insert located axially inward of the carcass reinforcement ply, the first rubber inset being generally lenticular in cross-sectional configuration and a second rubber insert located radially outward of the bead wire and axially outward of a main portion of the carcass reinforcement ply, wherein the main portion of the carcass ply extends between the bead wires; a total cross-sectional gauge of the rubber inserts is substantially constant from the radially outer surface of the bead wire to an axially outer end of the belt structure; and the first rubber insert has a radially innermost end that radially overlaps the second rubber insert, the overlap distance being in the range of 90 to 65% of the radial length of the second rubber insert.