To suppress a rain groove wandering phenomenon occurred on a rain groove road.
When groove width of a drain ditch 46 of the rain groove road 44 is made to WG, a shallow groove 40 is formed on a tread surface of a land part 16 and a tread surface of a shoulder block 32 only within a range of 0.9 WG-1.1 WG from a circumferential main groove 14 to a central side in a width direction of the land part 16, and rigidity of the land part 16 and a neighborhood to an edge at the circumferential main groove side of the shoulder block 32 is reduced. Thereby, a variation amount of shearing force is reduced when the land part 16 and the edge at the circumferential main groove side of the shoulder block 32 drop into the drain ditch 46, and the rain groove wandering phenomenon occurred when it travels on the rain groove road 44 is suppressed.
Kato Kazunori
Katsuichi Nishimoto
Hiroshi Fukuda