Sumitomo Rubber Industries Limited

Rubber Industries, Ltd.

Takao Kamijo

Eiji Nakasaki

Kazushige Ikeda

Hisashi Shirashoji

Yasuhiro Inoue

Katsuyuki Hoshikawa

Takeo Kato

A tire for a motorcycle comprising a tread, sidewalls extending inwardly from both ends of the tread in a radial direction, bead portions positioned at the radially inward ends of the sidewalls, a toroidal reinforcement carcass composed of reinforcement cords which extend approximately parallel with each other in the radial direction of the tire and of which both end portions are turned up around bead cores, a breaker arranged on the radially outer side of the carcass, the breaker comprising reinforcement tire cords whose tensile strength is not less than 7 g/d and initial modulus is not less than 200 g/d laid at angles of 10.degree. to 45.degree. to the circumferential direction, and a band over the breaker and having a width greater than the breaker so as to axially extend past the outermost edges of the breaker and comprising parallel reinforcement cords laid at angles of 10.degree. to 25.degree. to the circumferential direction, the reinforcement cords of the band having a modulus less than the modulus of the reinforcement cords of the breaker. The tire has resistance to wear, good grip, and stable high speed running properties.

Motorcycle tire with non-zero degree band radially outward of the breaker

Radial tires for motorcycles comprising a tread portion, side wall portions, bead portions, a carcass, bead apexes made of a rubber having a high hardness, and optionally reinforcing cord layers arranged outside the bead apexes, said tread portion having shoulder grooves at the shoulder portion thereof and center grooves at the center portion thereof and the depth of the shoulder grooves being from 5 to 50% of the depth of the center grooves, whereby cracking of the shoulder groove bottom caused by providing the bead apexes made of a hard rubber or the reinforcing cord layers is prevented.

Tire for motorcycles

Radial tires for motorcycles comprising a tread portion, side wall portions, bead portions, a carcass, a breaker, and optionally a reinforcing cord layer arranged outside the carcass and extending from one bead portion to the other bead portion and bead apexes made of a hard rubber, said tread portion having a plurality of longitudinal grooves in the circumferential direction at an angle of at least 5.degree. with respect to the cords of the most outer ply of the breaker. The motorcycle radial tires of the invention have an improved transverse stiffness at the side wall portions and moreover do not cause cracks at the bottom of the grooves in the tread portion.

Radial tire for motorcycles

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Toyonaka, Japan

Takao Kamijo