A center block and a second block that satisfy h1/H=0.05 to 0.4 and w1/W=0.05 to 0.4 are formed on a tread, where H is the block height, h1 is the drop in height of a chamfered part, w1 is the breadth of the chamfered part and W is the length of the block tread in a circumferential direction. When traveling on hard pavement, the chamfered part of the block contacts the hard pavement first and, compared to a case in which an edge that does not have a chamfered part contacts a hard pavement, the ground-contact surface area can be increased and steering stability on hard pavement can be improved. Further, in rough terrain, resistance received from a road surface at the time of ground contact is reduced, travel resistance is suppressed and steering stability is improved.