PNEUMATIC RADIAL TIRE

PROBLEM TO BE SOLVED: To lower the resonance sound of an air column and pattern vibration noise by providing a belt reinforcing layer in the periphery of a belt layer in a cross area of a rib, which is pinched by main grooves, and forming an area under the main groove into a non-belt reinforcing area. SOLUTION: A rib 4 is projected between main grooves 3, 3. A belt reinforcing layer 5 is provided in the periphery of both ends of the belt layer 2, and a belt reinforcing layer 6 is projected between the main grooves 3, 3 and provided under the rib 4. Namely, a rib cross area 7 between the main grooves 3, 3 is formed into a belt reinforcing area provided with the belt reinforcing layer 6, and an area 8 under the main groove 3 is formed into a non-belt reinforcing area, which is not provided with a belt reinforcing layer. Consequently, since bending rigidity of the main grooves 3, 3 is lowered, cross section of the groove is easily to be compressed for deformation when a load is applied, and resonance of a colunmar pipe is lowered, and while rigidity of the rib cross area 7 is improved, and as a result, vibration noise of hitting a road to be generated at the time of grounding or separating from the ground is lowered.