JP6457758B2 - Tires for motorcycles - Google Patents

Description

  The present invention relates to a pneumatic tire mounted on a two-wheeled vehicle.

  In recent years, two-wheeled vehicle tires are required to have low fuel consumption. To reduce fuel consumption, weight reduction is required. The weight can be reduced by reducing the number of carcass plies constituting the carcass. However, a tire with a reduced number of carcass plies has a reduced rigidity. This reduction in rigidity reduces steering stability.

  Japanese Patent Application Laid-Open No. 5-246210 discloses a tire including a reinforcing filler. The reinforcing filler includes a cord that is inclined at 30 ° or less with respect to the equator plane. By providing this reinforcing filler, a high lateral spring constant is obtained while the longitudinal spring rigidity of the tire is kept low. This tire has improved steering stability, turning stability and durability in high-speed running.

  Japanese Patent Application Laid-Open No. 10-244807 discloses a tire provided with a tread reinforcing layer inside the tread. The tread reinforcing layer includes a cord that is inclined at 0 ° to 30 ° with respect to the equator plane. In this tire, when the air is filled, the shoulder portion protrudes larger than the crown portion. Larger tension is generated in the cord at the shoulder than at the crown. This tension increases the rigidity of the shoulder. This tire has improved turning performance.

JP-A-5-246210 JP 10-244807 A

  By using this reinforcing filler or tread reinforcing layer, the rigidity can be improved even if the number of carcass plies is reduced. However, providing the reinforcing filler and the tread reinforcing layer increases the weight of the tire. Thus, it is not easy to achieve both weight reduction and rigidity improvement of the tire. An object of the present invention is to provide a pneumatic tire that is reduced in weight while suppressing a decrease in steering stability.

The pneumatic tire according to the present invention includes a tread, a pair of sidewalls, a pair of beads, a carcass, a center rubber layer, and a pair of side rubber layers. Each sidewall extends substantially inward in the radial direction from the tread end. Each bead is located on the axially inner side of the sidewall. The carcass includes a carcass ply. This carcass ply includes a cord and a topping rubber. The carcass ply is stretched between one bead and the other bead along the inside of the tread and the sidewall. The bead includes a core and an apex extending radially outward from the core. The center rubber layer is laminated on the outer side in the radial direction of the carcass and extends from one tread end to the other tread end. The pair of side rubber layers are laminated on the outer side in the axial direction of the carcass and extend from the tread end to the bead. The axial end portion of the center rubber layer is overlapped with the radially outer end portion of the side rubber layer. The radially inner end of the side rubber layer is overlapped with the apex. The complex elastic modulus E ^* c of the center rubber layer and the complex elastic modulus E ^* s of the side rubber layer are 30 MPa or more and 100 MPa or less.

  Preferably, each thickness of the center rubber layer and the pair of side rubber layers is 0.8 mm or more and 1.2 mm or less.

  Preferably, the loss tangent tan δc of the center rubber layer and the loss tangent tan δs of the pair of side rubber layers are set to 0.25 or less.

  Preferably, the overlapping width Wr in which the axial end portion of the center rubber layer and the radially outer end portion of the side rubber layer are overlapped is 10 mm or more and 15 mm or less.

  Preferably, the overlapping width Wt of the pair of side rubber layers overlapped with the radial inner ends and the apex is 5 mm or more and 15 mm or less.

  Preferably, the radially outer end of the side rubber layer is positioned on the inner side in the axial direction from the tread end. The radially outer end of the side rubber layer is located outside in the axial direction by a position of 10 mm from the tread end along the tread surface.

  Preferably, the tire includes a band stacked on the outer side in the radial direction of the carcass. The end of the band in the axial direction is located on the inner side in the axial direction from the outer end in the radial direction of the side rubber layer.

  Preferably, the thickness of the carcass cord is 940 dtex / 2 or more and 1400 dtex / 2 or less, and the density thereof is 30 ends / 5 cm or more and 60 ends / 5 cm or less.

  Since the tire according to the present invention includes the center rubber layer and the side rubber layer, the rolling resistance can be reduced while ensuring sufficient rigidity. This tire has excellent steering stability and can achieve low fuel consumption.

FIG. 1 is a cross-sectional view showing a part of a tire for a motorcycle according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a part of a two-wheeled vehicle tire according to another embodiment of the present invention.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 is a cross-sectional view showing a part of a tire 2 according to an embodiment of the present invention. The tire 2 is attached to a two-wheeled vehicle. In FIG. 1, the vertical direction is the radial direction of the tire 2, the left-right direction is the axial direction of the tire 2, and the direction perpendicular to the paper surface is the circumferential direction of the tire 2. A one-dot chain line CL in FIG. 1 represents the equator plane of the tire 2. The tire 2 has a substantially symmetrical shape with respect to the equator plane.

  The tire 2 includes a tread 4, a sidewall 6, a bead 8, a carcass 10, a band 12, an inner liner 14, a center rubber layer 16, and a side rubber layer 18. The tire 2 is a tubeless type pneumatic tire.

  The tread 4 is made of a crosslinked rubber and has a shape protruding outward in the radial direction. The tread 4 forms a tread surface 20 that contacts the road surface. Grooves may be formed on the tread surface 20. A tread pattern is formed by the groove being carved. A point Pe in FIG. 1 is an end of the tread surface 20 and indicates a tread end.

  The sidewall 6 extends substantially inward in the radial direction from the end of the tread 4. The sidewall 6 is made of a crosslinked rubber. The sidewall 6 absorbs an impact from the road surface by bending. The sidewall 6 prevents the carcass 10 from being damaged.

  The bead 8 is located inside the sidewall 6 in the radial direction. The bead 8 includes a core 22 and an apex 24. The core 22 has a ring shape. The apex 24 extends radially outward from the core 22. The apex 24 is tapered outward in the radial direction. The apex 24 is made of a highly hard crosslinked rubber.

  The carcass 10 is bridged between the beads 8 on both sides. The carcass 10 is along the inside of the tread 4 and the sidewall 6. The carcass 10 includes a carcass ply 26. The carcass ply 26 is wound around the bead 8 from the inner side to the outer side in the axial direction.

  The carcass ply 26 is wound around the bead 8 to form a main portion 26a and a folded portion 26b. The main portion 26 a extends from one bead 8 to the other bead 8 along the inside of the tread 4 and the sidewall 6. The folded portion 26b extends outward in the radial direction outside the bead 8 in the axial direction. A radially outer end portion 26 c of the folded portion 26 b is laminated on the side rubber layer 18.

  Although not shown, the carcass ply 26 includes a carcass cord and a topping rubber. This carcass cord is inclined with respect to the equator plane. The absolute value of the inclination angle formed with respect to the equator plane is 60 ° or more and 90 ° or less. In other words, the tire 2 is a radial tire. This carcass cord is usually made of organic fibers. Examples of preferable organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  The band 12 is located outside the carcass 10 in the radial direction. The band 12 is laminated on the center rubber layer 16. The band 12 is located on the inner side in the radial direction of the tread 4. The band 12 extends along the tread 4 from one axial end 12a to the other axial end 12a. The band 12 reinforces the carcass 10.

  Although not shown, the band 12 is made of a cord and a topping rubber. The cord is wound in a spiral. The cord extends substantially in the circumferential direction. The angle of the cord with respect to the circumferential direction is 5 ° or less, and further 2 ° or less. The cord is made of steel, for example. This cord may be made of organic fibers. Examples of organic fibers include nylon fibers, polyester fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  The inner liner 14 is joined to the inner peripheral surface of the carcass 10. The inner liner 14 is made of a crosslinked rubber. The inner liner 14 is made of rubber having excellent air permeability. The inner liner 14 plays a role of maintaining the internal pressure of the tire 2.

  The center rubber layer 16 is located on the inner side in the radial direction of the tread 4. The center rubber layer 16 extends along the tread 4 from one axial end 16a to the other axial end 16a. The center rubber layer 16 is laminated on the outer side in the radial direction of the carcass 10. The center rubber layer 16 is located between the band 12 and the carcass 10. The center rubber layer 16 extends from one tread end Pe to the other tread end Pe. The center rubber layer 16 is made of a highly hard crosslinked rubber.

  The side rubber layer 18 extends along the sidewall 6. The side rubber layer 18 is laminated on the outer side in the axial direction of the main portion 26 a of the carcass ply 26. In the tire 2, the axial end 16 b of the center rubber layer 16 and the radially outer end 18 c of the side rubber layer 18 are overlapped. The radially outer end 18 a of the side rubber layer 18 is located between the main portion 26 a and the center rubber layer 16. A radially inner end 18 d of the side rubber layer 18 is overlapped with the apex 24. The radially inner end 18 b of the side rubber layer 18 is located between the main portion 26 a and the apex 24. The radially inner end 18b may be positioned between the folded portion 26b and the apex 24. The outer end portion 26 c of the carcass ply 26 is laminated on the outer side in the axial direction of the side rubber layer 18. The side rubber layer 18 is made of a highly hard crosslinked rubber.

  A point Ps in FIG. 1 indicates an intersection point between the tread surface 20 and a straight line passing through the outer end 18 a of the side rubber layer and orthogonal to the tread surface 20. Point Pb indicates the intersection of the tread surface 20 with a straight line passing through the axial end 12 a of the band 12 and orthogonal to the tread surface 20. The point Ps is located on the tread surface 20 between the tread end Pe and the point Pb.

  A double arrow Ws indicates a distance from the tread end Pe to the point Ps. A double-headed arrow Wb indicates the distance from the point Ps to the point Pb. The distance Wb and the distance Ws are measured along the tread surface 20.

  A double-headed arrow Wc indicates the distance from the tip 24 a of the apex 24 to the outer end 16 a of the center rubber layer 16. A double-headed arrow Wr indicates the distance from the outer end 16a of the center rubber layer 16 to the outer end 18a of the side rubber layer 18. This distance Wr indicates a superposed polymerization width of the center rubber layer 16 and the side rubber layer 18. A double arrow Wt indicates a distance from the inner end 18 b of the side rubber layer 18 to the tip 24 a of the apex 24. In other words, the distance Wt indicates the overlapping width of the side rubber layer 18 and the apex 24 that are overlapped. The distance Wc, the polymerization width Wr, and the polymerization width Wt are measured along the side rubber layer 18.

The tire 2 includes a center rubber layer 16 and a side rubber layer 18 having high hardness. Even if the carcass 10 is composed of one carcass ply 26, the tire 2 can have sufficient rigidity. From the viewpoint of obtaining sufficient rigidity, the complex elastic modulus E ^* c of the center rubber layer 16 is set to 30 MPa or more. The complex elastic modulus E ^* s of the side rubber layer 18 is set to 30 MPa or more. On the other hand, from the viewpoint of suppressing the rigidity of the tire 2 from becoming too high, the complex elastic modulus E ^* c is set to 100 MPa or less. The complex elastic modulus E ^* s is set to 100 MPa or less.

From the viewpoint of obtaining sufficient rigidity to the side walls 6, the ratio ^{E *} s / ^E * e between the complex elastic modulus ^{E *} s of the complex elastic modulus ^{E *} e and the side rubber layer 18 of the apex 24, is 0.8 or more preferable. On the other hand, from the viewpoint of suppressing the rigidity of the sidewall 6 from becoming too high, the ratio E ^* s / E ^* e is preferably 1.2 or less. In the tire 2 in which the complex elastic modulus E ^* c of the center rubber layer 16 is large, the rigidity of the entire tread 4 and the pair of sidewalls 6 can be improved by the side rubber layer 18 and the center rubber layer 16. In this respect, the ratio ^{E *} c / ^E * e between the complex elastic modulus ^{E *} s of the complex elastic modulus ^{E *} c and the side rubber layer 18 of the center rubber layer 16 is preferably 0.7 or more. On the other hand, the tire 2 having a small complex elastic modulus E ^* c is suppressed from impairing the grip performance. From this viewpoint, the ratio E ^* c / E ^* e is preferably 1.0 or less.

  The center rubber layer 16 is made of a crosslinked rubber and does not have a cord. Since the cord is not provided, the strength to be reinforced does not differ depending on the planar direction in which the center rubber layer 16 expands. Similarly, since the side rubber layer 18 is made of a crosslinked rubber and does not include a cord, the strength to be reinforced does not vary depending on the planar direction. The tire 2 is similarly reinforced in the circumferential direction, radial direction, and other directions.

  In the tire 2, since the axial outer end portion 16 b of the center rubber layer 16 and the radial outer end portion 18 c of the side rubber layer 18 are overlapped, the rigidity of the shoulder region of the tread 4 is improved. In a two-wheeled vehicle, the vehicle body is tilted during turning. Turning is achieved by the camber thrust generated by this inclination. For the purpose of facilitating turning, the radius of curvature of the tread 4 is reduced. During this turning, the shoulder region of the tread 4 is grounded. Since the tire 2 has improved rigidity in the shoulder region, a large camber thrust can be generated. The tire 2 contributes to improvement of turning performance. The tire 2 contributes to improvement of steering stability during turning while suppressing an increase in weight to a minimum.

  From the viewpoint of improving the rigidity of the shoulder region of the tread 4, the outer end 18 a of the side rubber layer 18 is preferably positioned on the inner side in the axial direction than the tread end Pe. In other words, the point Ps in FIG. 1 is preferably located on the inner side in the axial direction from the tread end Pe. On the other hand, from the viewpoint of weight reduction, the distance Ws from the tread end Pe to the point Ps is preferably 10 mm or less.

  From the viewpoint of improving the rigidity of the shoulder region of the tread 4, the polymerization width Wr is preferably 10 mm or more, more preferably 11 mm or more, and particularly preferably 12 mm or more. Even if the polymerization width Wr exceeds 15 mm, it is difficult to obtain the effect of further improving the rigidity of the shoulder region. When the polymerization width Wr is large, the weight increases. From the viewpoint of weight reduction, the polymerization width Wr is preferably 15 mm or less, more preferably 14 mm or less, and particularly preferably 13 mm or less.

  From the viewpoint of improving the rigidity of the tire 2, the thickness of the center rubber layer 16 is preferably 0.8 mm or more, and more preferably 0.9 mm or more. On the other hand, if the thickness is too large, the rigidity of the tire 2 becomes too large. In particular, in the shoulder region where the center rubber layer 16 and the side rubber layer 18 are overlapped, the rigidity becomes too large. In addition, the weight of the tire 2 increases and the rolling resistance increases. From these viewpoints, this thickness is preferably 1.2 mm or less, and more preferably 1.1 mm or less. From the same viewpoint, the thickness of the side rubber layer 18 is preferably 0.8 mm or more, and more preferably 0.9 mm or more. The thickness of the side rubber layer 18 is preferably 1.2 mm or less, and more preferably 1.1 mm or less.

  Heat generation is suppressed in the tire 2 in which the loss tangent tan δc of the center rubber layer 16 is small. The tire 2 has reduced rolling resistance. Since the center rubber layer 16 is located on the inner side in the radial direction of the tread 4, the influence on the grip performance is suppressed. This tan δc is preferably as small as possible from the viewpoint of reducing rolling resistance. From this viewpoint, the loss tangent tan δc of the center rubber layer 16 is preferably 0.25 or less, more preferably 0.20 or less, and particularly preferably 0.15 or less. From the same viewpoint, the loss tangent tan δs of the side rubber layer 18 is preferably 0.25 or less, more preferably 0.20 or less, and particularly preferably 0.15 or less. The loss tangent tan δc and the loss tangent tan δs may be the same value.

  In the tire 2, since the inner end portion 18 d of the side rubber layer 18 is overlapped with the apex 24, the rigidity of the entire sidewall 6 in the radial direction is improved by the side rubber layer 18. In the radial direction, locally low rigidity portions are not formed on the sidewalls 6. It is suppressed that the side wall 6 bends locally. The tire 2 is excellent in durability. From this viewpoint, the polymerization width Wt is preferably 5 mm or more. On the other hand, in the tire 2 having a large polymerization width Wt, its weight increases. From the viewpoint of weight reduction, the polymerization width Wt is preferably 15 mm or less.

  In the tire 2, the axial end 12 a of the band 12 is positioned on the inner side in the axial direction from the outer end 18 a of the side rubber layer 18. The point Pb corresponding to the axial end 12a is located on the inner side in the axial direction from the point Ps corresponding to the outer end 18a. The band 12 is not overlapped with the portion where the center rubber layer 16 and the side rubber layer 18 are overlapped. The tire 2 is suppressed from becoming excessively rigid locally. In the tire 2, the occurrence of stress concentration is suppressed. The tire 2 is excellent in durability. From this viewpoint, the distance Wb is preferably 5 mm or more.

  In the tire 2, the center rubber layer 16 and the side rubber layer 18 reinforce the carcass 10. In the carcass 10, the entire structure from one bead 8 to the other bead 8 is reinforced. As a result, sufficient rigidity can be ensured even if the carcass cord is thinner and the density of the carcass cord is smaller than in the prior art. Thinning the carcass cord and reducing the density can contribute to weight reduction of the tire 2. From this viewpoint, the carcass cord is preferably 1400 dtex / 2 or less. This 1400 dtex / 2 indicates that two 1400 dtex filament bundles are twisted together to form one carcass cord. The density of the carcass cord is preferably 60 ends / 5 cm or less. This 60 ends / 5 cm indicates that the number of carcass cords to be driven per 5 cm width is 60. On the other hand, the tire 2 having a thick carcass cord and a large density is excellent in rigidity. From this viewpoint, the carcass cord is preferably 940 dtex / 2 or more, and the density thereof is preferably 30 ends / 5 cm or more.

  Here, the carcass cord is set to 940 dtex / 2 or more, 30 ends / 5 cm or more, 1400 dtex / 2 or less, 60 ends / 5 cm or less. The twist number of the bundle may be changed.

The loss tangent tan δ and the complex elastic modulus E ^* of the present invention are measured in accordance with the provisions of “JIS K 6394”. The loss tangent tan δ and the complex elastic modulus E ^* are measured under the following conditions.
Measuring device: Viscoelastic spectrometer "VES / F-3 type" (manufactured by Iwamoto Seisakusho)
Initial distortion: 10%
Dynamic distortion: 2%
Frequency: 10Hz
Deformation mode: Tensile
Measurement temperature: 70 ° C

  In the present invention, the dimension and angle of each member of the tire 2 are measured by a cross section cut out from the tire 2 as shown in FIG. In the present specification, the normal rim means a rim defined in a standard on which the tire 2 depends. “Standard rim” in the JATMA standard, “Design Rim” in the TRA standard, and “Measuring Rim” in the ETRTO standard are regular rims. In the present specification, the normal internal pressure means an internal pressure defined in a standard on which the tire 2 relies. “Maximum air pressure” in JATMA standard, “maximum value” published in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in TRA standard, and “INFLATION PRESSURE” in ETRTO standard are normal internal pressures.

  FIG. 2 shows a tire 28 according to another embodiment of the present invention. The tire 28 includes a carcass 30 in place of the carcass 10 of the tire 2. Other configurations of the tire 28 are the same as those of the tire 2. Here, the configuration of the tire 28 different from that of the tire 2 will be described. The description of the same configuration as the tire 2 is omitted.

  The carcass 30 is bridged between the beads 8 on both sides. The carcass 30 is along the inside of the tread 4 and the sidewall 6. The carcass 30 includes a carcass ply 32. The carcass ply 32 is wound around the bead 8 from the inner side toward the outer side in the axial direction.

  The carcass ply 32 is wound around the bead 8 to form a main portion 32a and a folded portion 32b. The main portion 32 a extends from one bead 8 to the other bead 8 along the inside of the tread 4 and the sidewall 6. The folded portion 32b extends outward in the radial direction outside the bead 8 in the axial direction. A radially outer end 32c of the folded portion 32b is laminated with the center rubber layer 16. The outer end portion 32 is laminated between the side rubber layer 18 and the center rubber layer 16.

  In the tire 28, the center rubber layer 16 and the outer end portion 32c of the carcass ply 32 are laminated. As a result, when air is filled with the normal internal pressure, tension is applied to the carcass cord at the folded portion 32. Due to this tension, the rigidity of the sidewall 6 is further increased. The tire 28 can exhibit high rigidity even if the carcass ply 32 has a single structure.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example 1]
A tire having the configuration shown in FIG. 1 was obtained. The tire size was “180 / 55ZR17”. The carcass of this tire is composed of one carcass ply, and the carcass ply is wound around the core from the inner side to the outer side in the axial direction. This carcass structure was a so-called 1-0 structure. This carcass cord was made of nylon fiber, and its density was 53 ends / 5 cm. The other configurations were as shown in Table 1.

[Comparative Example 1]
Conventionally, commercially available tires have been prepared. The carcass of this tire is composed of two carcass plies, and the two carcass plies are wound around the core from the inner side to the outer side in the axial direction. This carcass structure was a so-called 2-0 structure. This tire does not include a center rubber layer and a side rubber layer. Other configurations were the same as those in Example 1.

[Comparative Example 2]
A tire was obtained in the same manner as in Example 1 except that the center rubber layer and the side rubber layer were not provided.

[Comparative Example 3]
A tire was obtained in the same manner as in Example 1 except that the side rubber layer was not provided.

[Comparative Example 4]
A tire was obtained in the same manner as in Example 1 except that the center rubber layer and the side rubber layer were not overlapped and the side rubber layer and the apex were not overlapped.

[Comparative Example 5]
A tire was obtained in the same manner as in Example 1 except that the center rubber layer and the side rubber layer were not overlapped.

[Comparative Example 6]
A tire was obtained in the same manner as in Example 1 except that the carcass structure was changed to the 2-0 structure.

[Example 2-3]
A tire was obtained in the same manner as in Example 1 except that the complex elastic modulus E ^* c of the center rubber layer and the complex elastic modulus E ^* s of the side rubber layer were as shown in Table 2.

[Example 4-6]
Table 2 shows the thickness of the center rubber layer and the thickness of the side rubber layer. Tires were obtained in the same manner as in Example 1 for other configurations.

[Example 7-8]
A tire was obtained in the same manner as in Example 1 except that the loss tangent tan δc of the center rubber layer and the loss tangent tan δs of the side rubber layer were set as shown in Table 2.

[Example 9]
A tire was obtained in the same manner as in Example 1 except that the distance Wt from the inner end of the side rubber layer to the tip of the apex was changed as shown in Table 3.

[Example 10-11]
A tire was obtained in the same manner as in Example 1 except that the thickness of the carcass cord was changed as shown in Table 3.

[Comparative Example 7-8]
Conventional commercial tires were prepared. This tire had the same configuration as that of Comparative Example 1 except that the carcass configuration and the thickness of the carcass cord were as shown in Table 3.

[Steering stability]
A tire was incorporated into a regular rim, and the tire was filled with air so that the internal pressure was 290 kPa. This tire was mounted on the rear wheel of a two-wheeled vehicle having a displacement of 1000 cc (cm ² ). Commercial tires were installed on the front wheels. The rider was allowed to drive this motorcycle on the racing circuit and evaluate the handling stability. The results are shown in Table 1 below as an index with Comparative Example 1 as 100. Larger numbers are preferable. A tire having an index of 95 indicates a tire that is practically acceptable although it is slightly inferior to the tire of Comparative Example 1.

[cost]
The number of manufacturing steps per tire and the raw material cost of the tire were calculated. Index evaluation was performed with the tire of Comparative Example 1 as 100. In this evaluation result, the smaller the number, the lower the cost and the better.

[Rolling resistance coefficient]
Using a rolling resistance tester, the rolling resistance coefficient (RRC) was measured under the following measurement conditions.
Internal pressure: 290 kPa
Load: 1.30kN
Speed: 80km / h
The results are shown in Tables 1-3 below as indices based on Comparative Example 1. A smaller numerical value is preferable.

  As shown in Tables 1 to 3, the tires of the examples have higher evaluation than the tires of the comparative examples. From this evaluation result, the superiority of the present invention is clear.

  The tire described above can be widely applied to a pneumatic tire mounted on a motorcycle.

2, 28 ... Tire 4 ... Tread 6 ... Side wall 10, 30 ... Carcass 12 ... Band 14 ... Inner liner 16 ... Center rubber layer 18 ... Side rubber layer groove 20 ... tread surface 22 ... core 24 ... apex 26, 32 ... carcass ply

Claims (8)

A tread, a pair of sidewalls, a pair of beads, a carcass, a center rubber layer and a pair of side rubber layers,
Each sidewall extends substantially inward in the radial direction from the tread end,
Each bead is located axially inside the sidewall,
The carcass is composed of a single carcass ply, and the carcass ply includes a cord and a topping rubber, and the carcass ply includes one bead and the other bead along the inside of the tread and the sidewall. It is spanned between
The bead includes a core and an apex extending radially outward from the core;
The center rubber layer is laminated radially outward of the carcass, and extends from one tread end to the other tread end;
The pair of side rubber layers are laminated on the outside in the axial direction of the carcass and extend from the tread end to the bead,
The axial end of this center rubber layer is overlapped with the radially outer end of the side rubber layer, the radially inner end of the side rubber layer and the apex are overlapped,
A pneumatic tire for a two-wheeled vehicle in which the complex elastic modulus E ^* c of the center rubber layer and the complex elastic modulus E ^* s of the side rubber layer are 30 MPa or more and 100 MPa or less.   The tire according to claim 1, wherein each of the center rubber layer and the pair of side rubber layers has a thickness of 0.8 mm to 1.2 mm.   The tire according to claim 1 or 2, wherein the loss tangent tan δc of the center rubber layer and the loss tangent tan δs of the pair of side rubber layers are 0.25 or less.   The tire according to any one of claims 1 to 3, wherein a polymerization width Wr in which an axial end portion of the center rubber layer is overlapped with a radially outer end portion of the side rubber layer is 10 mm or more and 15 mm or less.   The tire according to any one of claims 1 to 4, wherein a superposition width Wt in which inner ends in the radial direction of the pair of side rubber layers are overlapped with an apex is 5 mm or more and 15 mm or less. The outer end in the radial direction of the side rubber layer is located on the inner side in the axial direction from the tread end,
When the intersection of the straight line perpendicular to the tread surface and the tread surface passing through the outer end in the radial direction of the side rubber layer is a point Ps, the point Ps extends axially from the position of 10 mm along the tread surface from the tread end The tire according to any one of claims 1 to 5, which is located outside. It has a band laminated on the outside in the radial direction of the carcass,
The tire according to any one of claims 1 to 6, wherein an end of the band in the axial direction is located on an inner side in the axial direction from an outer end in the radial direction of the side rubber layer. The tire according to any one of claims 1 to 7, wherein the carcass cord is 940 dtex / 2 or more and 1400 dtex / 2 or less, and the density is 30 ends / 5 cm or more and 60 ends / 5 cm or less.

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