Patent ID: 6550509
Filing Date: 2003-04-22
Classification: B60C,Y10T

Abstract:
A pneumatic radial ply runflat tire having a tread, two inextensible annular beads, a carcass comprising a radial ply structure having at least one radial ply, a belt structure located between the tread and the radial ply structure, and two sidewalls reinforced by one or more inserts, the tire being characterized by:a tread having a central region and adjacent laterally outermost disposed tread ribs; the central region of the tread defining an outer contour, and each tread rib defining an outer contour; a sidewall rib disposed near a radially outermost region of each sidewall adapted for contact with a driving surface during runflat operation and free from contact with the driving surface during operation at normal inflation pressure, each sidewall rib defining an outer contour; circumferentially extending first decoupling grooves disposed between each sidewall rib and each adjacent tread rib; circumferentially extending second decoupling grooves disposed between the central region of the tread and an adjacent tread rib; wherein: a circular curve that defines the contour of each respective laterally outermost disposed tread rib and a circular curve that defines the contour of the central region of the tread intersect nontangentially at each respective second decoupling groove; and a circular curve defining the contour of a respective radially outermost disposed sidewall rib and a circular curve defining the contour of a respective laterally outermost disposed tread rib intersect nontangentially at each respective circumferentially disposed first decoupling groove.