In a pneumatic tire, a first imaginary line passes through a ground contact surface in a meridian cross section of a tread portion and a second imaginary line passes through a bottom portion of a shoulder main groove and is parallel to the first imaginary line. Given A as a distance in the tire lateral direction between an intersection point of the first and second imaginary lines and a tire equatorial plane, B as a groove depth of the shoulder main groove, and C as a distance in the tire lateral direction between the ground contact edge and the tire equatorial plane, the condition 0.80(B+C)/A1.15 is satisfied and, given M as a distance in a tire radial direction between the bottom portion of the shoulder main groove and a belt layer, the condition 0.60B/(B+M)0.75 is satisfied.

In a tire 2, a difference Fs (((DdDe)/W)100) in an amount of protrusion is greater than 0.4 and less than 0.5. A sum Fa (((Dd+De)/W)100) of amounts of protrusions for a sidewall 6 satisfies mathematical expressions (3) and (4) in which an aspect ratio A is used, and a difference Gs (((DaDh)/W)100) in an amount of protrusion for a tread 4 satisfies mathematical expressions (6) and (7).
0.02626A1.8615<Fa(3)
Fa<0.02626A0.6615(4)
0.010819A0.084658<Gs(6)
Gs<0.010819A+0.6713(7)

A tire includes two beads, two sidewalls connected to the beads, and a crown. The crown includes a belt reinforcement, a tread, and a stiffening ply. The belt reinforcement has an axial width W. The tread includes tread pattern blocks and grooves having a groove bottom. The tread is made of a material that has a dynamic shear modulus G* of less than 1.25 MPa. The stiffening ply includes filamentary reinforcing elements that are rigid in terms of compression, and that are arranged under at least one of the grooves of the tread.

At a pneumatic tire (11), in a pneumatic tire in which a reinforcing layer (11) is structured from at least one reinforcing ply (53) in which are embedded plural reinforcing cords (54) that are formed from steel and are inclined with respect to a tire equator S, an inclination angle A of the reinforcing cords (54) with respect to the tire equator S is within a range of 40 to 90, and a compressive rigidity F per 50 mm width of a reinforcing layer (52) in a direction parallel to the reinforcing cords (54) is within a range of 1000 to 2400 N.

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.

Provided are: a tire reinforcement member capable of improving the tire durability than before; and a tire using the same. The present invention provides a tire reinforcement member 1 including: a core material cord layer 2; and a spiral cord layer 3 spirally wound on the core material cord layer 2, wherein cords in the core material cord layer 2 are metal cords 2a having an inclination angle of 40 to 90 with respect to the longitudinal direction of the core material cord layer 2, and reinforcing cords 3a in the spiral cord layer 3 are organic fiber cords having a modulus of not less than 19 GPa.

In a tire 2, a band 16 has a jointless structure. A reinforcing layer 18 is layered over the band 16 from a radially outer side of the band 16. In the reinforcing layer 18, a reinforcing cord 40 is extended alternately on and between one end 32 portion of the band 16 and the other end 32 portion of the band 16, so as to extend in the circumferential direction. A direction in which the reinforcing cord 40 extends is tilted relative to the circumferential direction between one of ends 32 of the band 16 and the other of the ends 32 of the band 16. An absolute value of an angle of the reinforcing cord 40 relative to the circumferential direction is greater than or equal to 70.

A pneumatic tire comprises a carcass layer, a belt layer disposed on an outer side of the carcass layer in a tire radial direction, and a tread rubber disposed on the outer side of the belt layer in the tire radial direction. The belt layer formed by laminating an angle belt having a belt angle 45 and 70 in absolute values, a pair of cross belts, having belt angles of 10 and 45 in absolute values and having belt angles of mutually opposite signs, and a circumferential reinforcing layer having a belt angle within a range of 5 with respect to a tire circumferential direction. A tread width TW and a cross-sectional width Wca of the carcass layer have a relationship such that 0.82TW/Wca0.92. A width Ws of the circumferential reinforcing layer and a cross-sectional width Wca of the carcass layer such that 0.60Ws/Wca0.70.

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.

A pneumatic tire includes a carcass layer, a belt layer that is disposed on the outer side in the tire radial direction of the carcass layer, and a tread rubber that is disposed on the outer side in the tire radial direction of the belt layer. The pneumatic tire also includes at least three circumferential main grooves extending in the tire circumferential direction, and a plurality of land portions that are defined by these circumferential main grooves. The belt layer includes an inner-side cross belt and outer-side cross belt having belt angles of not less than 51 and not more than 80 as absolute values with respect to the tire circumferential direction, the belt angles having mutually opposite signs, and a circumferential reinforcing layer having a belt angle that satisfies a range of 5 with respect to the tire circumferential direction.