Bridgestone Corporation

Toru Ubukata

Hajime Nakamura

Kazuyuki Hamamura

Kazuo Hayashi

Takayuki Fukunaga

Osamu Motoori

Masao Azuma

Hisao Ushikubo

The present invention realizes a pneumatic tire for a motorcycle, in which durability in running straight at a relatively high speed and tread surface gripping properties during high-speed cornering are made compatible and, in particular, a pneumatic tire for a motorcycle, which tire is capable of demonstrating appropriate durability and driving stability in accordance with inputs even if these inputs differ between running straight, cornering left and cornering right. The tread portionis constituted of plural types of rubbers-adjacent to each other in the tire widthwise direction and sectioned into at least a center region A at the center portion of the tire including the tire equatorial plane and two side regions B, Bat respective sides of the tire. 300% modulus of rubberconstituting the center region is higher than 300% modulus of each of rubbersconstituting the side regions, and 300% moduli of the rubbers constituting the side regions differ between one side region and the other side region.

Pneumatic tire for motorcycle

Tread portion of a motorcycle tire

Tread portion of an automobile tire

A pneumatic tire comprises at least one carcass ply of textile cords and a belt comprised of two cross belt layers containing textile cords arranged at a cord inclination angle of 10-45&deg; with respect to the equatorial plane, in which a difference of cord inclination angle between the two cross belt layers with respect to the equatorial plane of the tire is within a range of 5-35&deg; in the widthwise direction, and is mounted onto at least either left-side or right-side front wheel of a four-wheeled vehicle.

Reduced weight pneumatic tires

The pneumatic radial tire of the invention has a pair of bead portions each containing a bead core therein and is characterized in that each bead core is substantially constructed by winding at least one metal wire, and a bead toe reinforcing rubber stock with a JIS A hardness of 80.degree.-98.degree. is arranged inward of the outer edge of each bead core in an axial direction of the tire. In each bead portion the width of the bead toe reinforcing rubber stock is in a range of 0.5-2.0 times the width of the bead core in the axial direction. In each bead portion the width from the outer edge of the bead core to the inner edge of the bead portion in the axial direction of the tire is in a range of 1.1-3.0 times the width of the bead core in the axial direction of the tire. In each bead portion the side region in the axial direction of the tire and the inner region in the radial direction of the tire around the bead core and the bead toe reinforcing rubber stock are substantially reinforced by a chafer made of organic fiber cords.

Pneumatic radial tire with bead toe reinforcing rubber stock

Growing community of inventors

Kodaira, Japan

Toru Ubukata