Abstract: There is provided a pneumatic tire capable of improving high-speed durability and noise characteristics. The pneumatic tire has a belt-reinforcing structure 10 radially outwardly of belt plies 8 and 9, the belt-reinforcing structure 10 having organic fiber cords n spirally wound in the circumferential direction T of the tire. The belt-reinforcing structure 10 has an end reinforcement layer 10B disposed radially outwardly of each end region BE of the belt plies 8 and 9.

Abstract: Provided is a pneumatic radial tire: that includes a circumferential-direction reinforcement layer having a width increased with fatigue break of the circumferential-direction reinforcement layer being suppressed at edge portions thereof; and that suppresses separation in each of cross belt layers at edge portions thereof. A pneumatic radial tire according to the present invention is a pneumatic tire including: at least two cross belt layers disposed on an outer circumferential side of a carcass layer in a tread portion; and at least one circumferential-direction reinforcement layer disposed between these cross belt layers, a width of the circumferential-direction reinforcement layer being smaller than that of each cross belt layer.

Abstract: Disclosed is a pneumatic radial tire having improved flat spot resistance without sacrificing its high-speed durability, when a belt auxiliary reinforcement layer thereof is constituted of a hybrid fiber cord including a general-purpose nylon as a low-elastic fiber yarn. In the pneumatic radial tire, the belt auxiliary reinforcement layer is formed by winding an organic fiber cord around the outer periphery of belt layers in the tire circumferential direction. The organic fiber cord constituting the belt auxiliary reinforcement layer is obtained by twisting a highly-elastic fiber yarn with an elastic modulus of 10000 MPa or more and a low-elastic fiber yarn made of nylon 46.

Abstract: Disclosed is a pneumatic radial tire having improved high-speed durability and flat spot resistance in a well-balanced manner. Its carcass layer is constituted of a hybrid fiber cord obtained by imparting a first twist to a single nylon 46 fiber yarn and two aramid fiber yarns, and subsequently by twisting together the three fiber yarns while imparting a second twist to the three fiber yarns in a direction reverse to a direction of the first twist imparted to the three fiber yarns. In addition, a second twist coefficient K (expressed with T×D1/2) of this hybrid fiber cord is controlled in order to be 1700 to 2700.

Abstract: Provided is a pneumatic radial tire including a main belt layer and at least one circumferential-direction reinforcement layer, which are provided in the tread portion. The main belt layer includes two belt layers in which steel cords are disposed in a manner that the steel cords of a first one of the two belt layers intersect the steel cords of a second one of the two belt layers. In the circumferential-direction reinforcement layer, steel cords are disposed in a substantial tire circumferential direction. The ratio Wo/Wm of the width Wo of the circumferential-direction reinforcement layer to the maximum width Wm of the main belt layer is 0.5 to 0.9. The ratio Ee/Ec of the reinforcement-cord elastic modulus Ee of the steel cords in the edge portions of the circumferential-direction reinforcement layer to the reinforcement-cord elastic modulus Ec of the steel cords in the center portion of the circumferential-direction reinforcement layer is not less than (0.85-0.5 Wo/Wm) and not more than 0.8.

Abstract: A method of manufacturing a pneumatic tire according to the present invention can improve productivity. A steel cord S is continuously shaped in a helical manner or in a manner of a two-dimensional wave with at least one of amplitude and pitch of shaping of the steel cord varying in a phased manner or in a continuous manner just before winding of the steel cord S around a belt-forming drum 4. Then, the shaped steel cord S? is continuously wound around the rotating belt-forming drum 4 spirally in the circumferential direction of the drum in such a manner that the circumferential stiffness of a belt-reinforcing layer 16 varies in the widthwise direction of the tire.

Abstract: A tire/wheel assembly, wherein bent parts (4f) bent outward are formed at the leg end parts of an annular shell (4), an inclination angle (?1) of a line segment L1 extending from the axially outer end (P3) of the bent part (4f) through the apex (P1) of a hump (1f) on a rim relative to a direction perpendicular to a tire axis is set to within ±5° in a cross section orthogonal to the circumferential direction of the annular shell (4), the area (4s) of the annular shell equal to the height (B) of at least 35% of the height (A) from the radially inner end of the annular shell is formed linearly, the inclination angle (?2) of an extension line (L2) along the inner surface of the linear area (4s) relative to the direction perpendicular to the tire axis is 15 to 30° in axial inner side, and the extension line (L2) passes between the apex (P1) of the hump (1h) and the toe tip (P2) of a tire bead part.

Abstract: A pneumatic radial tire for passenger car capable of effectively lowering road noise by specifying the material characteristics and structure of a belt cover layer formed of aromatic polyamide fiber cords, wherein the belt cover layer formed of the aromatic polyamide fiber cords is wound on the outer peripheral side of a belt layer and the aromatic polyamide fiber cords are disposed around the tire at an angle of substantially 0° relative to the circumferential direction of the tire, characterized in that the intermediate elongation of the aromatic polyamide fiber cords at a load of 67N is 2.0 to 2.7% and the placing density of the aromatic polyamide fiber cords in the belt cover layer is 36 to 54 pieces/50 mm.

Abstract: A tire/wheel assembly, wherein bent parts (4f) bent outward are formed at the leg end parts of an annular shell (4), an inclination angle (?1) of a line segment L1 extending from the axially outer end (P3) of the bent part (4f) through the apex (P1) of a hump (1f) on a rim relative to a direction perpendicular to a tire axis is set to within ±5° in a cross section orthogonal to the circumferential direction of the annular shell (4), the area (4s) of the annular shell equal to the height (B) of at least 35% of the height (A) from the radially inner end of the annular shell is formed linearly, the inclination angle (?2) of an extension line (L2) along the inner surface of the linear area (4s) relative to the direction perpendicular to the tire axis is 15 to 30° in axial inner side, and the extension line (L2) passes between the apex (P1) of the hump (1h) and the toe tip (P2) of a tire bead part.

Abstract: Disclosed are a tire/wheel assembly and a run-flat support member which are designed to be lightened without losing durability during run-flat traveling. The tire/wheel assembly is constituted as follows: a pneumatic tire is fit to a wheel rim; and the run-flat support member constituted of a circular shell and elastic rings is inserted into a cavity of the pneumatic tire. The circular shell has a support surface thereof extended toward the periphery of the pneumatic tire and leg portions along each side of the support surface. The elastic rings support the leg portions of the circular shell on the rim. In the tire/wheel assembly, contact portions and noncontact portions for the circular shell are alternately formed on the elastic rings in a shell circumferential direction.

Abstract: Disclosed are a tire/wheel assembly and a run-flat support member which are designed to be lightened without losing durability during run-flat traveling. The tire/wheel assembly is constituted as follows: a pneumatic tire is fit to a wheel rim; and the run-flat support member constituted of a circular shell and elastic rings is inserted into a cavity of the pneumatic tire. The circular shell has a support surface thereof extended toward the periphery of the pneumatic tire and leg portions along each side of the support surface. The elastic rings support the leg portions of the circular shell on the rim. In the tire/wheel assembly, contact portions and noncontact portions for the circular shell are alternately formed on the elastic rings in a shell circumferential direction.