The tire has bead portions provided on inner sides of side wall portions which are provided on both sides of tread portion. The tread portion includes longitudinal grooves (1a-1e) extended in tire circumferential direction and side grooves (2a-2f) extended in lateral width direction. The rows of blocks (10-60) have block units (11-61) including three closed grooves (23a-23c) which have open end adjacent to longitudinal grooves. The inclination angles of closed grooves with respect to tire width direction are selected among different angles.
