TIRE

The tire comprises a widthwise narrow groove . The center-side narrow groove portion is formed, from groove opening side to groove bottom side, in a shape of a continuous series of: a narrow section including the groove opening; a tapered section where the groove width increases toward the groove bottom; a wide straight section extending in the groove depth direction with a constant groove width and having a groove width greater than that of the narrow section; and an arc-shaped section including the groove bottom, and the shoulder-side narrow groove portion is formed, from groove opening side to groove bottom side, in a shape of a continuous series of: a narrow section including the groove opening; a tapered section where the groove width increases toward the groove bottom; and an arc-shaped section including the groove bottom.