A pneumatic tire comprises a tread portion, sidewall portions, bead portions each with a bead core embedded therein, and a carcass extending between the bead portions and comprising first carcass cords and second carcass cords. The first carcass cord comprises: a main portion extending from the tread portion to the bead portions via the sidewall portions; and folded-back portions continued from the main portion and folded back around the bead cores from the inside to the outside in the tire axial direction. The second carcass cord extends from the tread portion to the bead portions and terminates on the axially outside of the folded-back portions of the first carcass cords. Young's modulus of the second carcass cords is larger than Young's modulus of the first carcass cords.

The present invention discloses a preparation method of polyester cord fabric with low denier and high modulus, including steps of: spinning, reducing melt discharge volume for extruding yarn with denier of 500-1000 D; using high-speed motor and heat roller, spinning speed of 6000-6500 m/min to produce raw yarn; performing initial and repeat twisting of raw yarn by straight twisting machine; performing weaving of twisted yarn using Dornier air-jet loom to produce cord fabric, when weaving and reeding-in, using two into a reed way, adding creel roller bearing and creel single spindle tension control belt to improve uniformity; performing dipping of cord fabric using two-bath dipping, adjusting temperature to 250-260 degrees Celsius, tension to 0.3-2.9 daN/each yarn of key area, running speed of yarn to 55-70 m/min. The polyester cord fabric with low denier and high modulus can reduce rolling resistance and fuel consumption, and improve performance.

The invention relates to a polyamide cord for use as carcass strength member in a pneumatic vehicle tire, wherein the polyamide cord has a residual shrinkage in the range from 0% to 2% and a shrinkage at 180 C. in the range from 0% to 4.5%, where the residual shrinkage of the polyamide cord and the shrinkage at 180 C. of the polyamide cord are determined to ASTM D 855. The invention also relates to a pneumatic vehicle tire comprising one or more polyamide cords and to a process for producing one or more polyamide cords, to a process for producing a rubberized reinforcement ply and to a process for producing a pneumatic vehicle tire.

In a pneumatic tire, a carcass layer mounted between bead portions includes composite cords made of polyethylene terephthalate fiber yarn having a fineness from 420-1200 dtex and an aromatic polyamide fiber yarn having a fineness from 520-1200 dtex, and a total fineness from 940-2400 dtex, and a twist coefficient from 1600 to 2400, the composite cords having an intermediate elongation from 2.0% to 4.5% with a load of 2.0 cN, having a dimensional stability index from 2.5% to 6.0% which is a sum of a dry heat shrinkage rate at 150 C. and the intermediate elongation with the load of 2.0 cN, and having a ratio of an initial elastic modulus at 100 C. within a load range from 0 N to 44 N with respect to an initial elastic modulus at 25 C. within a load range from 0 N to 44 N, the ratio being from 76% to 94%.

The reinforcing element (45) comprises an assembly (49) made up: of a multifilament strand made of aromatic polyamide or aromatic copolyamide (46) and of a multifilament strand made of polyester (48). The two strands (46, 48) are wound in a helix around one another, and the reinforcing element (45) is twist-balanced. The twist factor K of the reinforcing element (45) ranges from 5.5 to 6.5 where K is defined by the formula: K=(RTi.sup.1/2)/957 in which R is the twist of the reinforcing element (45) expressed in twists per metre and Ti is the sum of the counts of the multifilament strands of the reinforcing element (45) in tex.

Provided are a pneumatic tire with improved dimensional stability, low loss property, and durability and a method of producing the same. In a pneumatic tire, a rubber-fiber composite is used in at least any of a carcass ply and a cap ply, the rubber-fiber composite containing: a fiber cord made of polyamide multifilament fibers having a glass transition temperature in a range of 150 C. to 200 C.; and a rubber, a layer made of a resorcin-formalin-latex adhesive is formed at an interface between the fiber cord and the rubber, and a thermal contraction stress at 177 C. of the fiber cord with the layer formed thereon is 0.01 cN/dtex to 0.2 cN/dtex.

In a pneumatic tire including a carcass layer mounted between a pair of bead portions and a belt reinforcing layer disposed on an outer circumferential side of the carcass layer, the carcass layer is formed of a carcass cord made of an organic fiber cord, an elongation at break of the carcass cord is set to 20% or more, an elongation under a load of 1.5 cN/dtex of the carcass cord on the inner circumferential side of the belt layers is set to from 5.5% to 8.5%, the belt reinforcing layer is formed of a cover cord made of an organic fiber cord, and a tensile strength of the cover cord per width of 50 mm at a 3.0% elongation is set to from 2.8 kN to 4.0 kN.

The present application relates to the field of tires and provides a passenger all-steel tire and a turn-up process in a building process thereof. It is advantageous to improve tire strength, impact resistance, endurance and prolong service life. A longitudinal section of the passenger all-steel tire comprises a crown (1) located at an outer side of an upper portion, shoulders (2) located on two sides of the crown (1) and connected to the crown (1), a sidewall (3) connected to the shoulder (2), a bead (6) located at a lower portion of the sidewall (3) and matched with a rim, and a carcass (4) located at an inner side of the longitudinal section and the carcass (4) is a ply of all-steel carcass (41).

A motorcycle tyre, comprising a radial carcass structure (2) and a tread band (8) applied at a radially outer position with respect to the radial carcass structure (2), wherein the radial carcass structure (2) comprises a first carcass ply (3a) and a second carcass ply (3b) including a first plurality of textile reinforcing cords (30) and a second plurality of textile reinforcing cords (32), respectively, wherein the first textile reinforcing cords (31) are parallel to each other and the second textile reinforcing cords (33) are parallel to each other and have a respective first and second inclination at a crown portion (8c) of the tread band (8) with respect to an equatorial plane (X-X) of the tyre, wherein said second inclination is opposite to said first inclination. The first textile reinforcing cords (31) and the second textile reinforcing cords (33) have a tenacity comprised between 0.35 cN/Tex and 1.2 cN/Tex at 2% elongation and comprised between 0.5 cN/Tex and 3 cN/Tex at 5% elongation. At least one central annular sector (8a) of the tread band (8) arranged astride of the equatorial plane (X-X) is made of a vulcanized elastomeric material having a static elastic modulus Ca3 measured at 70 C. comprised between 9.0 and 14.0, a tandelta measured at 70 C. and 10 Hz comprised between 0.120 and 0.160, and a dynamic elastic modulus F measured at 70 C. and 10 Hz comprised between 3.7 and 4.1.

A tyre (1) for motorcycle wheels is described comprising a carcass structure (2), a belt structure (6) applied at a radially outer position with respect to the carcass structure (2), and a tread band (8) applied at a radially outer position with respect to the belt structure (6), wherein the carcass structure (2) comprises a carcass layer (2a) which comprises a plurality of reinforcing cords comprising one or more textile yarns comprising a plurality of textile filaments made of a material selected from rayon, PET, PEN, and PEEK, and/or hybrid reinforcing cords comprising a plurality of textile filaments made of a combination of two or more of rayon, PET, PEN, and PEEK, embedded in a vulcanized elastomeric material having a dynamic elastic modulus E measured at 70 C. and 100 Hz comprised between 5.0 and 9.0 MPa and a tandelta measured at 70 C. and 100 Hz comprised between 0.130 and 0.170. The vulcanized elastomeric material also comprises a white silica-based reinforcing filler and a residual unreacted amount of a silane coupling agent of the white silica-based reinforcing filler, expressed as an amount of silicon measured by ICP-OES, greater than or equal to 70 ppm.