PNEUMATIC RADIAL TIRE

PURPOSE:To improve uneven wear and abrasion resistance without deterioration of high speed draining property by disposing main and cross grooves crossing each other on a tread of a tire and forming the main groove of a plurality of crossing elements while one element has the groove bottom having the inclination degree less than that of the groove opening. CONSTITUTION:A tread of a tire is formed with main grooves 1a, 1b extending zigzag along the central peripheral line 0, a pair of peripheral grooves 2a, 2b extending parallel to the central peripheral line 0 and cross grooves 3a, 3b crossing the respective main grooves 1a, 1b from the tread end T and extending to converge to the central peripheral line 0. The main grooves 1a, 1b is formed of the repetition of a first element Y1 extending in the direction inclined to the tread end T side to the central peripheral line 0 and a second element Y2 extending in common with the respective cross grooves 3a, 3b to cross the first element Y1. The first element Y1 has an angle beta between the central peripheral line 0 and the center line l of the groove bottom section set less than that alpha between the central peripheral line 0 and the central line L of the groove opening section.