A pneumatic tire has a unidirectional tread pattern comprising right-hand and left-hand crown circumferential grooves and a crown rib formed therebetween. The crown rib is provided with first and second V-shaped grooves arranged alternately in the tire circumferential direction. The first V-shaped grooves extend from the left-hand crown circumferential groove. The second V-shaped grooves extend from the right-hand crown circumferential groove. The first and second V-shaped grooves are terminated within the rib, and their V-shape configurations have bending points substantially positioned at the tire equator.