Abstract: A golf ball can include a core, a mid layer, and a cover. An amount P(Na) of a sodium ion-neutralized ionomer resin in abase resin of the cover can be not greater than 5 parts by mass. The golf ball can satisfy the following mathematical formulas (1) and (2): Fm / ( Hm * Tm ) - Fc / ( Hc * Tc ) ? 3. , and ( 1 ) Mc * Tc ? 10. , ( 2 ) where Hm: hardness (Shore D) of the mid layer, Tm: thickness (mm) of the mid layer, Fm: bending stiffness (MPa) of the mid layer, Tc: thickness (mm) of the cover, Fc: bending stiffness (MPa) of the cover, and Mc: melt flow rate (g/10 min) of the cover at a temperature of 190° C. under a load of 2.16 Kg.

Abstract: A golf club head includes a loft between 20 degrees and 54 degrees and a main body including a top portion, a sole portion opposite the top portion, a heel portion, a toe portion opposite the heel portion, and a hosel portion extending from the heel portion. The hosel portion includes a hosel bore with an open end for receiving a golf club shaft and an abutment surface configured to support the golf club shaft, and an auxiliary recess extending sole-ward from the abutment surface, the auxiliary recess comprising a volume between 2 cubic centimeters and 3.5 cubic centimeters. The golf club head further includes a striking face defining a virtual face plane and having a face center, a virtual vertical plane perpendicular to the virtual face plane and extending through the face center, and a center of gravity spaced no more than 5 mm from the virtual vertical plane.

Abstract: A wood-type golf club head includes a depth in a front to rear direction no less than 80 mm, a striking face including a face center located in a virtual vertical center plane aligned with the face center and extending in the front to rear direction, a rear portion opposite the striking face, a heel portion, a toe portion opposite the heel portion, a crown, and a sole opposite the crown. The sole includes a first rail and a second rail projecting from the sole base surface and having a first length and a second length, respectively, in the front to rear direction that are less than 75% of the front to rear depth of the club head and the first rail and the second rail are entirely spaced in a heel to toe direction more than 15 mm from the virtual vertical center plane.

Abstract: Provided is a tire comprising a tread at least having two layers each comprising a rubber component and a plasticizer, wherein a difference (AE1?AE2) between an acetone extraction amount AE1 of the rubber composition of the first layer and an acetone extraction amount AE2 of the rubber composition of the second layer is greater than 6.0% by mass, and wherein, with the first layer and the second layer being attached together, when they are applied with a dynamic stimulus under a condition of a dynamic stress of 0.45 MPa, a frequency of 50 Hz, and a temperature at 80° C. for 120 hours, a rate of change in acetone extraction amount of the rubber composition of the first layer before and after being applied with the predetermined dynamic stimulus is ?10% or more and 10% or less.

Abstract: A pneumatic tire 1 has a bead portion provided with a reinforcing rubber portion disposed adjacently to the axially outer side of a carcass. The reinforcing rubber portion comprises an axially inner rubber layer and an axially outer rubber layer. The radially outer end of the axially outer rubber layer is positioned radially outside the radially outer end of the axially inner rubber layer. The radially inner end of the axially outer rubber layer is positioned radially inside the radially inner end of the axially inner rubber layer.

Abstract: A golf club head includes a striking face having a face center and a virtual striking face plane generally parallel to the striking face. The golf club head further includes a sole portion, a top portion, a rear portion, and a loft L no less than 40°. A virtual vertical plane perpendicular to the striking face plane passes through the face center. A club head center of gravity is spaced from the virtual vertical plane in the heel-to-toe direction by a distance D1 that is no greater than 6.0 mm. The golf club head further includes a hosel including an internal bore configured to receive a golf shaft. The internal bore includes a peripheral side wall and a shaft abutment surface configured to abut a tip end of the golf club shaft. The hosel further comprises an auxiliary recess extending sole-ward from the abutment surface of the internal bore.

Abstract: Provided is an evaluation method capable of evaluating stress on a bond which is difficult to detect by Raman spectroscopy. The present disclosure relates to an evaluation method including using infrared absorption spectra measured on a rubber specimen under application of no tensile force and under application of a tensile force to calculate an amount of peak shift caused by application of the tensile force, and evaluating stress in the rubber specimen from the amount of peak shift.

Abstract: A motorcycle tire comprises a tread reinforcement including a jointless band ply. The jointless band ply has a developed width Wa of not more than 65% of the developed tread width TWe. The tread portion has a tread profile comprising a crown arc portion having a radius R1 of curvature and a pair of shoulder arc portions having a radius R2 of curvature. The radius R1 is smaller than the radius R2 and smaller than 50% of the maximum tire cross-section width Wt. In a normal state of the tire, the axial ends of the crown arc portion are respectively positioned axially inward of the outer edges of the jointless band ply.

Abstract: Provided is a tire that allows reduction of uneven wear such as heel-and-toe wear around a plurality of closed sipes. The tire includes a tread portion 2. A plurality of closed sipes 8 are aligned in a tire axial direction in a land portion 4 of the tread portion 2. Each of the closed sipes 8 includes a sipe bottom 8d, a first end 8a and a second end 8b, a first sipe piece 11, a second sipe piece 12, a third sipe piece 13, and at least one tie bar 20. The closed sipes 8 aligned in the tire axial direction overlap each other in the tire axial direction and a tire circumferential direction. The tie bar 20 includes a first tie bar 21. A center, in a sipe length direction, of the first tie bar 21 is disposed closer to a first intersecting portion 18 than a center, in a length direction, of the first sipe piece 11 is. A distance from the first tie bar 21 to the first intersecting portion 18 is not greater than 25% of a length of the first sipe piece 11.

Abstract: A motorcycle tire includes a tread portion including a crown portion that is a region of 50% of a tread development width centered on a tire equator, a first shoulder portion that is an outer region of the crown portion, and first lateral grooves. Each lateral groove includes a first groove portion in the crown portion, a second groove portion in the first shoulder portion, and a third groove portion connecting the first and second groove portions. A groove depth and a groove width of the third groove portion are respectively smaller than groove depths and groove widths of the first groove portion and the second groove portion, respectively. More than 80% of a tire axial length of the third groove portion is in the first shoulder portion.

Abstract: An object of the present invention is to provide a golf ball having high visibility and little uncomfortableness at shot. The present invention provides a golf ball comprising a core and a cover disposed outside of the core, wherein a surface of the golf ball has a first region with a first color and a second region with a second color, the first color has hue H1 represented by H value in HSL color space, the second color has hue H2 represented by H value in HSL color space, and the H1 and the H2 satisfy a specific mathematical formula.

Abstract: An object of the present invention is to provide a golf ball having high visibility and excellent orientation at shot. The present invention provides a golf ball comprising a core and a cover disposed outside of the core, wherein a surface of the golf ball has a first region with a first color and a second region with a second color, the first color has hue H1 represented by H value in HSL color space, the second color has hue H2 represented by H value in HSL color space, and the H1 and the H2 satisfy the following mathematical formula (1): 60<|H1?H2|<300 ??(1).

Abstract: A golf club head includes a striking face having a face center and defining a face plane, a virtual vertical center plane perpendicular to the face plane and passing through the face center, a sole portion, a top portion, a heel portion, a toe portion, a hosel configured to receive a shaft, and a loft, L, no less than 39°. A center of gravity is spaced toe-ward from the vertical center plane by a distance, Dt, of greater than 0.0 mm. A moment of inertia, Iyy, measured about an axis extending in a heel to toe direction, parallel with a ground plane, passes through the center of gravity such that Iyy is no less than 1150 g·cm2.

Abstract: A motorcycle tire has a tread portion. The tread portion has a ground contact surface curved in an arc shape convex outward in a tire radial direction. The ground contact surface includes a central region and a first outer region. The ground contact surface has oblique grooves each including a portion inclined with respect to a tire circumferential direction. Each of the oblique grooves extends across the central region and the first outer region. Each of the oblique grooves includes a vertical groove portion extending at an angle ? of 20 degrees or less with respect to the tire circumferential direction. A minimum distance in a tire axial direction along the ground contact surface between the vertical groove portion and an outer edge of the central region is 30% or less of a maximum width in the tire axial direction of the central region along the ground contact surface.

Abstract: A contour CL of a carcass 12 includes a curved portion 44 and an inversely curved portion 46. A boundary between the curved portion 44 and the inversely curved portion 46 is an inflection point PV. A part or an entirety of the curved portion 44 is represented by a first arc. A part or an entirety of the inversely curved portion 46 is represented by a second arc. The first arc and the second arc are tangent to each other at the inflection point PV. A ratio (X/W) of a distance X in an axial direction to a distance W in the axial direction is not less than 70% and not greater than 85%. A ratio (Y/H) of a distance Y in a radial direction to a distance H in the radial direction is not less than 15% and not greater than 22%.

Abstract: A tire comprises a tread portion having a tread surface and buttress surfaces. The buttress surfaces have inclinations such that the tread edges shift axially outwards as the tread portion is worn off. The tread rubber includes a radially outermost first rubber layer and a radially inner second rubber layer. The loss tangent ?2 of the second rubber layer is larger than the loss tangent ?1 of the first rubber layer. One of or each of the buttress surfaces is provided with an outer lateral groove. The outer lateral groove is located axially outside the tread edge when the tire is new, and when the tread portion is worn off and the tread edge shifts axially outward, the outer lateral groove is at least partially located axially inward of the tread edge.

Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in hardness over time. The present invention relates to a rubber composition containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber composition having a heat aging resistance index defined by equation (1) of 10 or less.

Abstract: A tire comprises a tread portion comprising at least one land portion having a first longitudinal edge, a second longitudinal edge, and a ground contacting top surface therebetween. The land portion is provided with first sipes, second sipes and third sipes. Each first sipe is inclined with respect to the tire axial direction to a first direction. Each second sipe is inclined with respect to the tire axial direction to a direction opposite to the first direction. The third sipe comprises a first oblique portion extending from the first longitudinal edge and inclined to the first direction, and a second oblique portion extending from the second longitudinal edge and inclined to a direction opposite to the first direction.

Abstract: An object of the present disclosure is to provide a golf ball having stable directionality on a driver shot while maintaining or improving a flight distance on a driver shot for a golfer with a slow head speed. The present disclosure provides a golf ball comprising a spherical core, and an outermost cover positioned outside the spherical core and having a plurality of dimples formed thereon, wherein a hardness difference S(=Hs?Ho) between a surface hardness Hs of the spherical core and a center hardness Ho (Shore C hardness) of the spherical core, a material hardness C (Shore D hardness) of the outermost cover, and a total volume V (mm3) of the plurality of dimples below a surface of a virtual sphere satisfy V×(S+C)/1000?50.

Abstract: A tire has a tread portion comprising a first middle land portion provided with first middle lateral grooves, and a second middle land portion provided with second middle lateral grooves. The first middle lateral grooves are each inclined to one direction. The second middle lateral grooves each comprise a first oblique portion and a second oblique portion which are inclined to different directions. In a plan view of the tread portion, when virtual extension zones are defined by extending the respective second middle lateral grooves in parallel with the tire axial direction, an overlapping area between each of the virtual extension zones and the opening of one of the first middle lateral grooves is not more than 50% of the area of the opening.