Pneumatic tire with tread having rib shaped land section, lug grooves and sipes

A pneumatic tire (10a) including in a tread at least two circumferential major grooves (21a, 22a) extending in a tire circumferential direction and a rib-shaped land section continuously extended in the tire circumferential direction via a sipe (40a) that extends in a tire width direction, the pneumatic tire comprising:

• lug grooves (30a, 31a, 30a) extending in the tire width direction, each of which includes an end closed by the rib-shaped land section and the other end open to one of the at least two circumferential major grooves (21a, 22a), the open ends being arranged in the staggered fashion in the tire circumferential direction;
• and
• first sipes (40a, 41a) which include the sipe (40a) extending in the tire width direction and another sipe (41a) extending in the tire circumferential direction, and connect the lug grooves (30a, 31a, 30a) arranged in the staggered fashion;
• wherein
• a block is defined by the one of the at least two circumferential major grooves (21a, 22a), the lug grooves (30a, 31a, 32a), and the first sipes (40a, 41a),
• the block includes two second sipes (50a, 51a),
• the two second sipes (50a, 51a) are extended in the tire width direction, one end thereof respectively open to one of the at least two circumferential major grooves (21a, 22a), and the other end thereof respectively open to the first sipes (40a, 41a),
• the second sipes (50a, 51a) divide the block into two wide sections being wide in the tire circumferential direction and a narrow section being narrower than the two wide sections in the tire circumferential direction,
• the narrow section is arranged between the two wide sections,
• the lug grooves (30a, 31a, 30a) include a first lug groove (30a), a second lug groove (31a) and a third lug groove (32a), and
• the sipe (40a) extending in the tire width direction connects the first lug groove (30a) and the second lug groove (31a) arranged in the staggered fashion, and the other sipe (41a) extending in the tire circumferential direction connects the second lug groove (31a) and the third lug groove (32a) arranged in the staggered fashion.