Abstract: The offset amount that a sacrificial rib road contact surface is recessed to the inner side of a tire with regards to a shoulder rib road contact surface is equal to 0, and a circumferential fine groove is provided such that the opening side thereof is located on the inner side when the tire is filled to a proper internal pressure. The dimension Ws in the tire width direction of the shoulder rib road contact surface and the dimension Wa in the tire width direction of the sacrificial rib road contact surface are set such that 0.10?Wa/Ws?0.2. The dimension Wb in the tire width direction of the sacrificial rib road contact surface when the groove depth of the circumferential main grooves has worn 20% is set in a range such that 0.25?Wb/Ws?0.30.

Abstract: [Problem] To improve uneven wear resistance. [Resolution Means] The offset amount H that the road contact surface of a sacrifice rib 42 is recessed to the inner side in the tire radial direction with regards to the road contact surface of a shoulder rib 41 is equal to 0, and a circumferential fine groove 5 is provided at an angle such that the opening side thereof is located on the inner side in the tire width direction when the tire is filled to a proper internal pressure. Furthermore, with regards to the dimension Ws in the tire width direction of the road contact surface of the shoulder rib of a new tire, the dimension Wa in the tire width direction of the road contact surface of the sacrifice rib of a new tire is set such that 0.10?Wa/Ws?0.2, the dimension Wb in the tire width direction of the road contact surface of the sacrifice rib when the groove depth of the circumferential main grooves has worn 20% is set in a range such that 0.25?Wb/Ws?0.