Patent ID: 8627863

Claim:
A tire comprising a rib-shaped land portion extending along a tire circumferential direction, which is adjacent to a circumferential groove extending along the tire circumferential direction wherein an air chamber in which a recessed portion recessed toward an inside in the tire radial direction repeats at predetermined pitches along the tire circumferential direction and a constriction groove communicating to the recessed portion are formed on the rib-shaped land portion, assuming a highest position being a grounding surface at which the rib-shaped land portion makes contact with a road surface, a bottom surface of the air chamber gradually changes, along the tire circumferential direction, from a portion where a depth from the grounding surface is deepest to the highest position, a volume of a space formed by the constriction groove and the road surface is smaller than a volume of a space formed by the recessed portion and the road surface, one end of the constriction groove communicates to a closed space formed by the air chamber and the road surface, and the other end of the constriction groove communicates to the circumferential groove, the bottom surface provided between two highest positions adjacent each other and the grounding surface contacting with the rib-shape land portion form the air chamber, wherein the bottom surface of the air chamber repeats an arch shape in a cross sectional view along the tire circumferential direction; wherein the center of the arch shape is positioned at a further inner inside of a tire radial direction than the bottom surface.