Radial pneumatic tire having contoured zones in the sidewalls

摘要

The present invention relates to a radial pneumatic tire having a contoured zone located in each of the sidewalls of the tire. The contoured zone improves the sidewalls ply durability and decreases upper sidewall circumferential ply-wire breakage, also known as zipper-break. More particularly, the radial pneumatic tire comprises (1) at least one circumferential reinforcing belt; (2) a pair of sidewalls extending from opposing edges of said reinforcing belt to corresponding tire beads and containing a single reinforcing cord ply that wraps around each bead and having two terminal ends; (3) an inner cavity; (4) a contoured zone, wherein said contoured zone is (a) located between said single reinforcing cord ply and said inner cavity, (b) is circumferentially extending about the axis of the tire, (c) located in a region of each sidewall defined by the area from said reinforcing belt to the terminal ends of said single reinforcing cord ply, and (d) wherein the distance between the single reinforcing cord ply and said inner cavity is greater in the region where the contoured zone is located in comparison to the distance between the single reinforcing cord ply and said inner cavity in the region beneath said reinforcing belt.