Abstract: A motorcycle tire pair includes a front tire 2 and a rear tire 42. A center arc index Ac, a middle arc index Am, and a shoulder arc index As are obtained based on a contour line TLf of a tread surface 16 of the front tire 2 and a contour line TLr of a tread surface 56 of the rear tire 42. In the tire pair, the middle arc index Am is greater than or equal to the center arc index Ac, and the shoulder arc index As is smaller than the center arc index Ac.

Abstract: A tire includes a tread portion including four circumferential grooves between outboard and inboard tread edges, and five land portions divided by the circumferential grooves. The circumferential grooves include an inboard shoulder circumferential groove located nearest to the inboard tread edge in the circumferential grooves. The land portions include an inboard shoulder land portion disposed axially outward of the inboard shoulder circumferential groove and having a ground contact surface with the smallest axial width in the land portions. The inboard shoulder land portion is provided with inboard shoulder lateral grooves and inboard shoulder sipes. The inboard shoulder lateral grooves include inner ends away from the inboard shoulder circumferential groove. The inboard shoulder lateral grooves extend axially outward from the inner ends to a location beyond the inboard tread edge. The inboard shoulder sipes extends from the inboard shoulder circumferential groove to a location beyond the inboard tread edge.

Abstract: In a tire 12, a tread 14 includes a tread main body 44 and edge portions 46. A wear resistance index of each edge portion 46 obtained according to JIS K6264-2 is higher than that of the tread main body 44. An outer surface S of the tire 12 includes a tread surface ST, a pair of shoulder surfaces SH connected to the tread surface ST, and a pair of side surfaces SW connected to the shoulder surfaces SH. Each shoulder surface SH includes an outer surface formed by the edge portion 46, and a contour of each shoulder surface SH is represented by a circular arc having a center at an inner side.

Abstract: A tire is provided with blocks in a tread portion. Each of the blocks has a block wall surface provided with first recesses. Each of the first recesses extends across a block ground contacting surface and the block wall surface. Each of the first recesses has a triangular ground contacting surface opening on the block ground contacting surface and a triangular wall surface opening on the block wall surface. The wall surface opening has a first end terminating without reaching a groove bottom of one of grooves demarcating the each of the blocks.

Abstract: An object of the present disclosure is to provide a golf ball having good shot feeling and excellent durability while having non-lowered resilience. The present disclosure provides a golf ball comprising a spherical core and one or more cover layers disposed outside the spherical core, wherein at least one layer of the cover layers contains (A) a base resin and (B) a polyethylene oxide.

Abstract: An object of the present disclosure is to provide a golf club grip comprising an inner layer that is hard to collapse and has excellent weather resistance. The present disclosure provides a golf club grip comprising a cylindrical portion having a cylindrical inner layer and a cylindrical outer layer provided outside the cylindrical inner layer, wherein the cylindrical inner layer is formed from an inner layer rubber composition containing an acrylonitrile-butadiene based rubber as (A1) a base rubber, and the inner layer rubber composition has a maximum torque value of 0.5 Nm or more in a vulcanization curve measured at a temperature of 165° C. and an amplitude angle of one degree.

Abstract: A composite cord is composed of two first strands formed of aramid fibers and one second strand formed of nylon fibers. In a cross section perpendicular to a length direction, a ratio L2/L0 of a length L2 of an exposed surface of the second strand along the outer cord periphery to a length L0 of an exposed surface of the composite cord along the outer cord periphery is in a range of 0.30 or more and 0.40 or less.

Abstract: An object of the present invention is to provide a golf ball having excellent shot feeling while maintaining the resilience performance on driver shots. The present invention provides a golf ball comprising a core and at least one cover covering the core, wherein the core is formed from a core rubber composition containing (a) a base rubber, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d) a monophenol compound having a substituent group only at p-position.

Abstract: A tire in which an elongation at break and/or compounding of a rubber composition of a tread.

Abstract: A tire includes a tread portion that includes a first circumferential groove and a first land portion. A groove bottom portion of the first circumferential groove includes a groove bottom reference surface and a plurality of projections projecting outwardly in a tire radial direction from the groove bottom reference surface. The first land portion has at least one first lateral groove extending from the first circumferential groove and terminating within the first land portion. In a tread plan view, an entirety of a first lateral groove extension region obtained by extending a connection portion of the first lateral groove at the first circumferential groove to the groove bottom portion of the first circumferential groove so as to be parallel to a tire axial direction is formed on the groove bottom reference surface.

Abstract: A tyre includes a tread portion including a tyre equator, a tread edge, a tread width which is a distance in a tyre axial direction from the tyre equator to the tread edge, a shoulder land portion including the tread edge. The shoulder land portion is provided with a plurality of first shoulder lateral grooves. Each first shoulder lateral groove includes an inner groove portion extending inwardly in the tyre axial direction of the tread edge and an outer groove portion extending outwardly in the tyre axial direction of the tread edge. Each first shoulder lateral groove, in a tread development view, has a groove area Sb of the outer groove portion extending in a region from the tread edge to an 125% position of the tread width is greater than a groove area Sa of the inner groove portion.

Abstract: A tire state determination system (100) acquires, from a vehicle (50), state data that includes various types of information that may exert influence on deterioration of a base body portion of a tire (1), and calculates an evaluation value S that indicates a state of the base body portion of the tire (1), based on the acquired state data. This allows an inspector who inspects an applicability to a base tire, to preliminarily grasp, as a material for determining whether it can be used as the base tire, the state of the base body portion of the tire.

Abstract: A performance evaluation method for elastic material including rubber or elastomer, the method includes: a step of applying a strain to a test piece made of an elastic material to form at least one low-density portion inside the test piece; after forming the low-density portion, a step of obtaining projected images of the test piece by irradiating the test piece with X-rays at a predetermined first time and at a second time after the first time; a step of identifying the low-density portion based on the projected images at the first time; a step of identifying the low-density portion based on the projected images at the second time; a step of identifying a volume change of the at least one low-density portion between the first time and the second time; and a step of outputting the volume change as one of indicators of performance of the elastic material.

Abstract: A golf club head includes a striking face, a sole portion, a top portion, a hosel, a rear surface, a loft no less than 40°, a virtual vertical plane, and a center of gravity. The striking face has a face center, a leading edge, and a virtual striking face plane. The hosel includes an internal bore configured to receive a golf shaft and includes a peripheral side wall and a shaft abutment surface configured to abut a tip end of the golf shaft. The rear surface is opposite the striking face and has an upper portion and a lower portion, the lower portion including a forward-extending recess. The insert covers the recess forming a hollow portion. The virtual vertical plane is perpendicular to the striking face plane and passes through the face center. The center of gravity is spaced a distance from the virtual vertical plane in the heel-to-toe direction.

Abstract: A golf club head has a hollow portion therein. The golf club head includes a head main body comprising a striking face portion, a crown portion and a sole portion, the head main body being provided with a recess extending in a toe-heel direction of the club head on at least one of the crown portion and the sole portion, and a reinforcing rod being fixed to the recess and extending in the toe-heel direction of the club head.

Abstract: An object of the present invention is to provide a production method of a diene-based polymer that can control the crosslinking morphology. The present invention provides a method for producing a modified diene-based polymer having a structure represented by the formula (1), comprising a first step of mixing a diene-based polymer and a dithioester compound to prepare a mixture; and a second step of irradiating a ray to the mixture under an inert atmosphere. [In the formula (1), R1 and R2 represent an alkyl group having 1 or more carbon atoms, an aryl group having 6 or more carbon atoms, an aralkyl group having 6 or more carbon atoms, a hydrogen atom, or a halogen atom; and Z is an organic group, an organic group where a part of hydrogen atom of the above organic group is substituted, a hydrogen atom, or a halogen atom.

Abstract: A pneumatic tire has a pair of sidewall portion 3. An outer surface of at least one of the pair of sidewall portions 3 includes a decorative region 5 extending in a tire circumferential direction. In the decorative region 5, a plurality of pattern elements 8 are arranged, whereby the decorative region 5 includes a plurality of circumferential pattern lines 6 in each of which the pattern elements 8 are aligned in the tire circumferential direction, and a plurality of radial pattern lines 7 in each of which the pattern elements 8 are aligned in a tire radial direction. In each circumferential pattern line 6, lengths in the tire circumferential direction of the pattern elements 8 are changed in the tire circumferential direction. In each radial pattern line 7, lengths in the tire radial direction of the pattern elements 8 are changed in the tire radial direction.