Abstract: A tire center slant groove near tread surface tire equatorial plane extends toward reverse rotation-direction of designated rotation-direction while slanting from a tire equatorial plane side to a tire-width direction outer side, an extension direction angle forms with respect to a tire circumference-direction within range, 3°-10°; and at center slant groove-end portion in reverse rotation-direction, at least a tire-width direction outer side groove-edge of the center slant groove forms into a circular-arc-shaped portion to have the tire-width direction outer side groove-edge angle formed with respect to tire circumference-direction, the angle increasing toward reverse rotation-direction, the tire-width direction outer side groove-edge angle of the center slant groove forms with respect to tire circumference-direction larger than an angle of a tire-width direction inner side groove-edge of the center slant groove forms with respect to tire circumference-direction, and the center slant groove depth gradually d

Abstract: A pneumatic tire for a motorcycle that secures durability while improving grip performance in turning. A pneumatic tire for a motorcycle including a belt containing a belt layer formed by coating a plurality of cords with rubber in a tire tread, wherein the tread is provided with cushion rubbers separated from each other in the tire widthwise direction in both sides of the tire equatorial plane by a separated region and located outward in the tire radial direction from the belt, and a base rubber having a modulus higher than those of the cushion rubbers located in the separated region or outward in the tire radial direction therefrom, and Wn, a length of the separated region, and Wb, a length of the base rubber in the cross section in the tire widthwise direction, satisfy the relation: Wn?Wb.

Abstract: The present invention aims at providing a pneumatic tire for a motorcycle, capable of improving steering stability and wear resistance in a turning situation with maintaining good turning performance achieved by a relatively wide auxiliary belt layer. Specifically, the present invention provides a pneumatic tire for a motorcycle, characterized in that: the auxiliary belt layer is sectioned into a middle area Am overlapping a region where the belt layer is provided and respective side areas As each extending beyond the region where the belt layer is provided; the cords in the middle area Am extend at an inclination angle ?m in the range of 70° to 90° with respect to the tire circumferential direction; and the cords in each side area As extend, in at least a portion of the side area, at an inclination angle ?s different from the inclination angle ?m with respect to the tire circumferential direction.

Abstract: A tire center slant groove near tread surface tire equatorial plane extends toward reverse rotation-direction of designated rotation-direction while slanting from a tire equatorial plane side to a tire-width direction outer side, an extension direction angle forms with respect to a tire circumference-direction within range, 3°-10°; and at center slant groove-end portion in reverse rotation-direction, at least a tire-width direction outer side groove-edge of the center slant groove forms into a circular-arc-shaped portion to have the tire-width direction outer side groove-edge angle formed with respect to tire circumference-direction, the angle increasing toward reverse rotation-direction, the tire-width direction outer side groove-edge angle of the center slant groove forms with respect to tire circumference-direction larger than an angle of a tire-width direction inner side groove-edge of the center slant groove forms with respect to tire circumference-direction, and the center slant groove depth gradually d

Abstract: A motorcycle pneumatic tire includes a belt, in a tire tread, including a circumferential belt layer formed by cords extending in the tread circumferential direction and covered by rubber and a width direction belt layer, provided outward in the tire radial direction from the circumferential belt layer, formed by cords extending in the tire width direction and covered by rubber; sections of cushion rubber, provided outward in the tire radial direction from the belt, separated in the tire width direction with the tire equatorial plane therebetween; and base rubber, provided in the area of separation between the sections of cushion rubber or outward in the tire radial direction from the area of separation, having a higher elastic modulus than the cushion rubber. Wn>Wb, where Wn is the length of the area of separation and Wb is the length of the base rubber in a tire width direction cross-section.

Abstract: The present invention aims at providing a pneumatic tire for a motorcycle, capable of improving steering stability and wear resistance in a turning situation with maintaining good turning performance achieved by a relatively wide auxiliary belt layer. Specifically, the present invention provides a pneumatic tire for a motorcycle, characterized in that: the auxiliary belt layer is sectioned into a middle area Am overlapping a region where the belt layer is provided and respective side areas As each extending beyond the region where the belt layer is provided; the cords in the middle area Am extend at an inclination angle ?m in the range of 70° to 90° with respect to the tire circumferential direction; and the cords in each side area As extend, in at least a portion of the side area, at an inclination angle ?s different from the inclination angle ?m with respect to the tire circumferential direction.

Abstract: A pneumatic tire for a motorcycle that secures durability while improving grip performance in turning. A pneumatic tire for a motorcycle including a belt containing a belt layer formed by coating a plurality of cords with rubber in a tire tread, wherein the tread is provided with cushion rubbers separated from each other in the tire widthwise direction in both sides of the tire equatorial plane by a separated region and located outward in the tire radial direction from the belt, and a base rubber having a modulus higher than those of the cushion rubbers located in the separated region or outward in the tire radial direction therefrom, and Wn, a length of the separated region, and Wb, a length of the base rubber in the cross section in the tire widthwise direction, satisfy the relation: Wn?Wb.

Abstract: A radial tire for a motorcycle capable of having high road grip performance both when running at a high speed on a dry road surface and when cornering at a high speed, together with the high speed durability, especially a radial tire for a motorcycle with a large displacement to be used for road races, capable of maintaining these performances until the end of the races, is provided. The tilting angles of the cords 13a of said cross-belt 13 are set to 60 degrees or more to the circumferential direction, and a belt protecting layer 15 is disposed outside the spiral-belt 14, the belt protecting layer 15 having cords arranged in the direction tilted at 70 degrees or more to the circumferential direction.

Abstract: A radial tire for a motorcycle capable of having high road grip performance both when running at a high speed on a dry road surface and when cornering at a high s]peed, together with the high speed durability, especially a radial tire for a motorcycle with a large displacement to be used for road races, capable of maintaining these performances until the end of the races, is provided. The tilting angles of the cords 13a of said cross-belt 13 are set to 60 degrees or more to the circumferential direction, and a belt protecting layer 15 is disposed outside the spiral-belt 14, the belt protecting layer 15 having cords arranged in the direction tilted at 70 degrees or more to the circumferential direction.

Abstract: A piston ring comprising a generally I shaped oil-scraping oil ring which has upper and lower side rails and a considerably thin web connecting the side rails, and which has an outer peripheral channel for receiving scraped oil and an inner peripheral groove for receiving coil expander, and an annular coil expander which is located in the inner peripheral groove so that the coil expander bears against the upper and lower side rails substantially at two points, the coil expander being spaced from the web of the oil ring with a slight gap therebetween.