Bridgestone Tire Company Limited

Bridgestone Corporation

Yoichi Kitazawa

Shinichiro Ohkuni

Takeshi Sato

Hisao Tsuji

Shinichiro Okuni

Naoki Yamazaki

Toshiharu Kikutsugi

Toru Osawa

A pneumatic radial tire for motorcycle is disclosed, which comprises a tread, a pair of sidewalls, a carcass composed of at least one rubberized ply containing organic fiber cords arranged in a direction of approximately 90.degree. with respect to the equatorial plane of the tire, and a belt disposed between said tread and said carcass at a width corresponding to a tread width and composed of at least two rubberized plies each containing cords with a modulus of elasticity of at least 600 kg/mm.sup.2 arranged at an inclination angle of 15.degree.-30.degree. with respect to the equatorial plane of the tire. In the tire, each end of the carcass is wrapped around a bead ring embedded in each radially inner end portion of the sidewalls toward a direction of the tread to form a turnup portion; a tapered rubber filler extending from an upper part of the bead ring toward the tread direction and having a Shore A hardness of at least 60.degree., and at least one cord reinforcing layer extending upward from a position near the bead ring along the turnup portion and having an inclination cord angle of 15.degree.-30.degree. with respect to the circumferential direction of the tire are disposed between the carcass and the turnup portion thereof or outside the turnup portion; and at least one of radial heights extending from the bead base to ends in the tread direction of the rubber filler, cord reinforcing layer and turnup portion corresponds to at least 60% of the radial height of the sidewall.

Pneumatic radial tires for motorcycles

A pneumatic semi-radial tire for motorcycle is disclosed, which comprises a tread, a pair of sidewalls, a carcass composed of at least one rubberized ply containing organic fiber cords inclined at an angle of 50.degree.-85.degree. with respect to the equatorial plane of the tire, and a belt disposed between said tread and said carcass at a width corresponding to a tread width and composed of at least two rubberized plies each containing cords with a modulus of elasticity of at least 600 kg/mm.sup.2 arranged at an inclination angle of 15.degree.-30.degree. with respect to the equatorial plane of the tire. In the tire, each end of at least one rubberized ply constituting the carcass is wrapped around a bead ring embedded in each radially inner end portion of the sidewalls toward a direction of the tread to form a turnup portion in which cords of the carcass are crossed with cords of the turnup portion in the sidewall; a stiffener inclusive of a tapered rubber filler extending from an upper part of the bead ring toward the tread direction and having a Shore A hardness of at least 60.degree. is disposed between the carcass and the turnup portion thereof or outside the turnup portion; and at least one of radial heights extending from the bead base to ends in the tread direction of the stiffener and turnup portion corresponds to at least 60% of the radial height of the sidewall.

Pneumatic semi-radial tires for motorcycles

A pneumatic tire for high-speed running type motorcycles is disclosed, which comprises a carcass of a bias structure composed of at least two plies each containing organic fiber cords, a tread portion of rubber, a breaker disposed between the carcass and tread and composed of at least one ply containing organic fiber cords, and a side portion of rubber. In the pneumatic tire, the carcass and breaker are arranged in substantially parallel with each other, and the carcass has a cord angle of 26.degree.-36.degree. with respect to the equatorial plane of the tire, and the breaker has a cord angle of 0.degree.-25.degree. with respect to the equatorial plane and extends at a width corresponding to 30-200% of the tread width.

Pneumatic tires for high-speed running type motorcycles

A pneumatic belted tire for use in motorcycles is disclosed, which comprises a toroidal carcass, a tread superimposed about a crown region of the carcass at a width corresponding to the maximum width of the carcass and provided on its surface with a tread pattern, and a belt arranged on the crown region over the width of the tread and composed of plural rubberized layers each containing inextensible cords inclined at an angle of not less than 30.degree. with respect to the equatorial plane. In this type of the tire, the inclination angle of cords in the belt gradually enlarges within a range of 7.degree.-20.degree. from the center of the crown region toward the tread side edge, and the tread is provided on each side edge portion with a substantially continuous rib having a width corresponding to 5-25% of the tread width.

Pneumatic belted tires

A pneumatic tire for motorcycle having an excellent absorbability to external disturbances is disclosed, which comprises a tread having a laminate structure inclusive of a base rubber having a storage modulus of 50-90 kg/cm.sup.2 and a ratio of loss tangent to storage modulus of 2.5.times.10.sup.-3 -5.times.10.sup.-3 and a cap rubber having a storage modulus at least equal to that of the base rubber.

Pneumatic tire for motorcycle having an excellent absorbability to

A pair of pneumatic belted tires for use in motorcycle are disclosed, each of which comprises a tread extending over a width corresponding to the maximum width of the tire, a pair of sidewalls, a pair of bead portions each containing a bead core therein, a carcass composed of at least one rubberized ply containing organic fiber cords inclined at an angle of 50.degree.-90.degree. with respect to the equatorial plane of the tire, and a belt composed of at least two rubberized plies each containing cords arranged at a certain inclination angle with respect to the equatorial plane. In such a tire pair, an inclination angle .alpha. of cord in the belt for rear wheel tire and an inclination angle .beta. of cord in the belt for front wheel tire satisfy the following relationship:

Pair of pneumatic belted tires for motorcycle

A space saving spare tire usually stored in a vehicle and used in the case of emergency travel on road when a puncture failure or the like is induced in a tire mounted on the vehicle and run on road. The spare tire comprises an internal pressure penetration preventive cord layer superimposed about the crown portion of a toroidal carcass and a cushion rubber layer interposed between the internal pressure penetration preventive cord layer and the toroidal carcass and having a gauge which is at least equal to that of a coating rubber interposed between the carcass plies.

Space save spare tire

A light weight pneumatic tire having a thin side wall rubber is disclosed. The thin side wall rubber has previously been squeezed on that region of the outer surface of an upper ply which corresponds to the side wall portion of the tire prior to the tire shaping step, and has a Shore A hardness after vulcanization of 40.degree. to 55.degree., an excellent flex-cracking and weather resistant property. The upper ply is superimposed about at least a portion extending from a hump portion to a bead portion is composed of cords coated with a high resilient rubber. A tread rubber layer is extended across the thin side wall rubber layers and pressed and made integral therewith by stitching.

Light weight pneumatic tire having a thin side wall rubber

A light weight pneumatic tire having a thin side wall rubber is disclosed. The thin side wall rubber has previously been squeezed on that region of the outer surface of an upper ply which corresponds to the side wall portion of the tire prior to the tire shaping step and possessed of a Shore A hardness after vulcanization of 40.degree. to 55.degree., an excellent flex-cracking and weather resistant property. The upper ply is superimposed about at least a portion extending from a hump portion to a bead portion of the tire and composed of cords coated with a high resilient rubber. A tread rubber layer is extended across the thin side wall rubber layers and pressed and made integral therewith by stretching.

Growing community of inventors

Higashiyamato, Japan

Yoichi Kitazawa