Abstract: A cold-workable mechanical structural steel may include: C: 0.30 to 0.45 mass %; Si: 0.10 to 0.40 mass %; Mn: 0.50 to 1.00 mass %; P: 0.050 mass % or less; S: 0.050 mass % or less; Cr: 0.80 to 1.30 mass %; Al: 0.01 to 0.10 mass %; and a balance of iron and inevitable impurity, the steel having an area percentage of pro-eutectoid ferrite of 10% or larger and 70% or smaller; containing at least one selected from the group consisting of bainite, martensite, and pearlite; and having a dislocation density of 3.5×1014 m?2 or larger.

Abstract: Each sipe wall surface of a sipe in a tread portion of a pneumatic tire includes, along a sipe depth direction, multiple ridge portions and at least one valley portion bending like waves. Where viewed along the sipe depth direction, a recess depth of the valley portion with respect to the ridge portion on one wall surface varies depending on a position in the extension direction, the valley portion extends from a position at which the recess depth is maximized toward a position at which the recess depth is minimized, and the recess depth decreases as the valley portion extends from the side of the maximum-depth valley portion toward the maximum ridge portion. The sipe is provided in at least one of a first half-tread region on a first side or a second half-tread region on a second side in a tire width direction.

Abstract: In a tread portion of a pneumatic tire, a first sipe wall surface of a sipe includes at least two first peak portions and at least one first valley portion at each position of the sipe extension direction, which are bent in a wave-like shape to form surface recesses and protrusions along a sipe depth direction. The first valley portion is sandwiched between the two first peak portions in the sipe depth direction, and extends from one end of the sipe in the extension direction to the other end of the sipe in the extension direction. A recess depth of the first valley portion with respect to the two first peak portions gradually reduces. A position of at least one of the two first peak portions in the sipe depth direction and a position of the first valley portion in the sipe depth direction become gradually closer.

Abstract: A pneumatic tire tread pattern includes a center main groove extending in a circumferential direction, first and second inclined lug grooves located on respective first and second sides in a lateral direction and extending from the center main groove toward the respective first and second sides in the lateral direction with respect to the circumferential direction, and inner branched lug grooves each branched from a middle of a corresponding one of the first and second inclined lug grooves, inclined identically to an inclination direction of the first and second inclined lug grooves, and connected to the center main groove. The first and second inclined lug grooves include a center portion extending outward from the center main groove in the lateral direction, an outer portion extending inward from a shoulder side in the lateral direction, and a bent portion at which the center and outer portions are bent and connected together.

Abstract: Each sipe wall surface of a sipe in a tread portion of a pneumatic tire includes, along a sipe depth direction, multiple ridge portions and at least one valley portion bending like waves. Where viewed along the sipe depth direction, a recess depth of the valley portion with respect to the ridge portion on one wall surface varies depending on a position in the extension direction, the valley portion extends from a position at which the recess depth is maximized toward a position at which the recess depth is minimized, and the recess depth decreases as the valley portion extends from the side of the maximum-depth valley portion toward the maximum ridge portion. The sipe is provided in at least one of a first half-tread region on a first side or a second half-tread region on a second side in a tire width direction.

Abstract: In a tread portion of a pneumatic tire, a first sipe wall surface of a sipe includes at least two first peak portions and at least one first valley portion at each position of the sipe extension direction, which are bent in a wave-like shape to form surface recesses and protrusions along a sipe depth direction. The first valley portion is sandwiched between the two first peak portions in the sipe depth direction, and extends from one end of the sipe in the extension direction to the other end of the sipe in the extension direction. A recess depth of the first valley portion with respect to the two first peak portions gradually reduces. A position of at least one of the two first peak portions in the sipe depth direction and a position of the first valley portion in the sipe depth direction become gradually closer.

Abstract: A pneumatic tire tread pattern includes a center main groove extending in a circumferential direction, first and second inclined lug grooves located on respective first and second sides in a lateral direction and extending from the center main groove toward the respective first and second sides in the lateral direction with respect to the circumferential direction, and inner branched lug grooves each branched from a middle of a corresponding one of the first and second inclined lug grooves, inclined identically to an inclination direction of the first and second inclined lug grooves, and connected to the center main groove. The first and second inclined lug grooves include a center portion extending outward from the center main groove in the lateral direction, an outer portion extending inward from a shoulder side in the lateral direction, and a bent portion at which the center and outer portions are bent and connected together.

Abstract: A pneumatic tire includes at least three circumferential grooves extending in the tire circumferential direction in the tread portion, and at least four ribs extending in the tire circumferential direction. In the pneumatic tire, at least two of the ribs including a rib disposed on a first side of the tire equatorial plane in the tire width direction and a rib disposed on a second side protrude to the outer side in the tire radial direction beyond a profile line of a tread surface when viewed in a meridian cross section. The protruding amount decreases in order from the first side to the second side in the tire width direction, and the loss tangent tan ? at 60° C. of the compound in a region where the rib has the least protruding amount is smaller than that in a region of the rib where the protruding amount is the greatest.

Abstract: The pneumatic tire (1) comprises at least three circumferential grooves (22) extending in a tire circumferential direction in a tread portion (2), and at least four ribs (23) defined by the circumferential grooves (22), the at least four ribs (23) extending in the tire circumferential direction. At least two of the ribs (23) protrude outward in a tire radial direction beyond the profile line (L) of the tread surface when viewed in the meridian cross section. The protruding amount (G) of the at least two ribs (23) decreases in order from a first side in a tire width direction to a second side.

Abstract: A pneumatic tire includes at least three circumferential grooves extending in a tire circumferential direction in the tread portion, and at least four ribs defined by the at least three circumferential grooves, the at least four ribs extending in the tire circumferential direction. At least two of the ribs including the rib disposed on a first side of a tire equatorial plane in a tire width direction and the rib disposed on a second side protrude to an outer side in a tire radial direction beyond a profile line of a tread surface when viewed in the meridian cross section. The protruding amount decreases in order from the first side in the tire width direction to the second side, and the groove surface area ratio of the tread surface is greater on the second side of the tire equatorial plane in the tire width direction than on the first side.

Abstract: A pneumatic tire includes at least three circumferential grooves extending in the tire circumferential direction in the tread portion, and at least four ribs extending in the tire circumferential direction. In the pneumatic tire, at least two of the ribs including a rib disposed on a first side of the tire equatorial plane in the tire width direction and a rib disposed on a second side protrude to the outer side in the tire radial direction beyond a profile line of a tread surface when viewed in a meridian cross section. The protruding amount decreases in order from the first side to the second side in the tire width direction, and the loss tangent tan ? at 60° C. of the compound in a region where the rib has the least protruding amount is smaller than that in a region of the rib where the protruding amount is the greatest.

Abstract: A pneumatic tire includes at least three circumferential grooves extending in a tire circumferential direction in the tread portion, and at least four ribs defined by the at least three circumferential grooves, the at least four ribs extending in the tire circumferential direction. At least two of the ribs including the rib disposed on a first side of a tire equatorial plane in a tire width direction and the rib disposed on a second side protrude to an outer side in a tire radial direction beyond a profile line of a tread surface when viewed in the meridian cross section. The protruding amount decreases in order from the first side in the tire width direction to the second side, and the groove surface area ratio of the tread surface is greater on the second side of the tire equatorial plane in the tire width direction than on the first side.

Abstract: The pneumatic tire (1) comprises at least three circumferential grooves (22) extending in a tire circumferential direction in a tread portion (2), and at least four ribs (23) defined by the circumferential grooves (22), the at least four ribs (23) extending in the tire circumferential direction. At least two of the ribs (23) protrude outward in a tire radial direction beyond the profile line (L) of the tread surface when viewed in the meridian cross section. The protruding amount (G) of the at least two ribs (23) decreases in order from a first side in a tire width direction to a second side.