Motorcycle tire

Abstract

To provide a motorcycle tire capable of increasing vibration absorbability to improve steering stabilizing performance while maintaining high rigid feeling during traveling.SOLUTION: A motorcycle tire 1 comprises an installation rubber layer 10 disposed between a body 6a of a carcass ply 6A and an inner liner layer 9. The installation rubber layer 10 extends from a first end 10e of a tread 2 side to at least a bead core 5. A side wall 3 includes an outermost end t1 of the tire in a radial direction in which a normal rim R comes into contact with a tire outer surface 1s of the side wall 3. The tire outer surface 1s of the side wall 3 is provided with a side profile 3S which occupies, from a tread end Te, to 90% or more of a tire radial length La between the tread end Te and the outermost end t1. The side profile 3S is linear or a circular arc in which a curvature radius r1 is 55 mm or larger and which is projected inside in a tire axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire for a motorcycle. [Background technology]

[0002] Patent Document 1 below describes a pneumatic tire having insulation located between a carcass and an inner liner, the insulation being disposed in at least the sidewall portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-074834 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned tires have dramatically increased rigidity in the sidewall portion and are said to have excellent rigidity during driving. In recent years, there has been a demand for motorcycle tires that have improved vibration absorption while maintaining a high rigidity during driving.

[0005] The present invention has been devised in view of the above circumstances, and has as its main object to provide a motorcycle tire that can improve steering stability by increasing vibration absorption while maintaining a high sense of rigidity during driving. [Means for solving the problem]

[0006] The present invention is a tire for motorcycles, comprising: a tread portion defining a pair of tread edges; a pair of sidewall portions extending radially inward from the tread portion; a pair of bead portions provided radially inward of the sidewall portions, each having a bead core; a carcass including a carcass ply having a toroidal main body portion extending between the pair of bead cores; an inner liner layer disposed on the tire cavity side of the carcass; and an insulation rubber layer disposed between the main body portion and the inner liner layer in each of the pair of sidewall portions, wherein each of the insulation rubber layers extends from a first end on the tread portion side to a second end of the carcass. and the tire outer surface of each of the pair of sidewall portions includes a side profile that occupies 90% or more of the length in the tire radial direction between the tread edge and the outermost edge in the tire radial direction from the tread edge to the outermost edge, and the side profile is a straight line or an arc that has a curvature radius of 55 mm or more and is convex inward in the tire axial direction. [Effects of the Invention]

[0007] By adopting the above-described configuration, the present invention can improve steering stability by increasing vibration absorption while maintaining a high sense of rigidity during driving. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a tire meridian cross-sectional view of a motorcycle tire according to one embodiment of the present invention. [Figure 2] 1 is a tire meridian cross-sectional view of a tire 1. FIG. [Figure 3] FIG. 2 is an enlarged view of a sidewall portion of the tire 1 of FIG. [Figure 4] FIG. 10 is an enlarged view of a sidewall portion of another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will now be described with reference to the drawings. The drawings include exaggerated representations and representations different from the dimensional ratios of the actual structures to facilitate understanding of the present invention. Furthermore, when there are multiple embodiments, the same or common elements are designated by the same reference numerals throughout the specification, and redundant explanations will be omitted.

[0010] Fig. 1 is a tire meridian cross-sectional view in a normal state including a tire rotation axis (not shown) of one embodiment of a motorcycle tire (hereinafter sometimes simply referred to as "tire") 1 of the present invention. The tire 1 of this embodiment is preferably mounted on a motorcycle suitable for on-road sports riding. However, the tire 1 of the present invention is not limited to this embodiment.

[0011] In this specification, unless otherwise specified, the dimensions of each part of the tire 1 are measured in the normal state. The "normal state" refers to a state in which the tire 1 is mounted on a normal rim R, inflated to the normal internal pressure, and no load is applied.

[0012] "Genuine rim R" is the rim that is specified for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called "standard rim," in the case of TRA, it is called "Design Rim," and in the case of ETRTO, it is called "Measuring Rim."

[0013] "Normal internal pressure" is the air pressure specified for each tire by each standard in the standard system, including the standard on which the tire is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE."

[0014] The tire 1 of this embodiment includes a tread portion 2 that defines a pair of tread edges Te, a pair of sidewall portions 3 that extend radially inward from the tread portion 2, and a pair of bead portions 4 that are provided radially inward of the sidewall portions 3. Each bead portion 4 is provided with a bead core 5. The tread edges Te correspond to the ends of the tire outer surface 1t of the tread portion 2, and are the ends that come into contact with the road surface when cornering at the maximum camber angle.

[0015] The tire 1 includes a carcass 6 and an inner liner layer 9 disposed on the tire cavity 1B side of the carcass 6. The carcass 6 includes a carcass ply 6A having a roid-shaped main body portion 6a extending between the pair of bead cores 5. The tire 1 also includes an insulation rubber layer 10 disposed between the main body portion 6a and the inner liner layer 9 in each of the pair of sidewall portions 3.

[0016] Each of the insulation rubber layers 10 extends from a first end 10e on the tread portion 2 side to at least the bead core 5. Such insulation rubber layers 10 can increase the rigidity of the sidewall portion 3.

[0017] In the normal state, each of the pair of sidewall portions 3 includes an outermost end t1 in the tire radial direction where the normal rim R and the tire outer surface 1s of the sidewall portion 3 come into contact.

[0018] In the tire meridian cross section in the normal state, the tire outer surface 1s of each of the pair of sidewall portions 3 has a side profile 3S that occupies 90% or more of the tire radial length La from the tread edge Te to the tread edge Te and the outermost edge t1. The side profile 3S is an arc that convex axially inward with a curvature radius r1 of 55 mm or more. The sidewall portion 3 having such a side profile 3S ensures a sufficient stroke for the entire sidewall portion 3 to flex, allowing the entire sidewall portion 3 to absorb vibrations during driving, thereby improving vibration absorption. Therefore, the motorcycle tire of the present invention has excellent steering stability. A straight side profile 3S (with an infinite curvature radius r1) can also achieve the same effect, but a side profile 3S of 300 mm or less is preferable, and a side profile of 60 mm or more is preferable.

[0019] Additionally, the tire outer surface 1s of each of the pair of sidewall portions 3 has a minor side profile 3T that occupies 5% or more of the tire radial length La from the outermost end t1. The minor side profile 3T is formed as an arc that convexly faces inward in the tire axial direction. Such a minor side profile 3T helps the entire sidewall portion 3 to better absorb vibrations during running. The radius of curvature r2 of the minor side profile 3T is, for example, preferably 10.0 mm or more, more preferably 12.0 mm or more, and more preferably 17.0 mm or less, and even more preferably 15.0 mm or less. Each of the minor side profile 3T and the side profile 3S is formed, for example, as an arc with a single radius of curvature.

[0020] The tire outer surface 1s of this embodiment includes a peak 14 connecting the side profile 3S and the secondary side profile 3T. The peak 14 protrudes outward in the tire axial direction. For example, the peak 14 may be formed as a so-called rim line that is provided so that, when assembling the tire to the rim, it can be visually determined whether the tire 1 and the standard rim R are properly assembled. In this embodiment, the peak 14 extends continuously in the tire circumferential direction. The peak 14 of this embodiment is formed as a vertex. The peak 14 is not limited to this form.

[0021] In a meridian cross section of the tire in a normal state, the tire outer surface 1t of the tread portion 2 includes a tread profile 2S that is a circular arc shape that protrudes outward in the tire radial direction.

[0022] The tread profile 2S includes a pair of outer contact positions 2e, which are the outermost contact positions in the tire axial direction when the tire 1 in the normal state is loaded with a normal load and inclined at a camber angle of 30 degrees on each side of a pair of tread edges Te and brought into contact with a flat surface. The tread profile 2S of this embodiment also includes a first portion 21 extending between the outer contact positions 2e and a pair of second portions 22 extending between the pair of outer contact positions 2e and the tread edges Te. The first portions 21 are contacted with the ground during straight running and cornering with a large turning radius. A relatively small lateral force acts on this first portion 21. The second portions 22 are contacted with the ground during cornering with a small turning radius, such that the tread edges Te come into contact with the road surface. These second portions 22 are contacted with the ground when the camber angle is in the range of more than 30 degrees and approximately 45 degrees. A relatively large lateral force acts on this second portion 22.

[0023] The "normal load" is the load determined for each tire by each standard in the standard system, including the standard on which the tire is based. In the case of JATMA, it is the "maximum load capacity," in the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and in the case of ETRTO, it is the "LOAD CAPACITY."

[0024] The first portion 21, which is subjected to a relatively small lateral force, desirably has a small contact patch width (not shown) to absorb vibrations during driving by utilizing the flexure of the tread portion 2. Conversely, the second portion 22 desirably has a large contact patch width to improve steering stability through stable cornering. For this reason, in the tread profile 2S, the radius of curvature r4 of the second portion 22 is desirably larger than the radius of curvature r3 of the first portion 21. To improve steering stability from straight driving to cornering with a small turning radius, in the tread profile 2S, the radius of curvature r3 of the first portion 21 is desirably 40 mm or more, more desirably 45 mm or more, preferably 60 mm or less, and more desirably 55 mm or less. Furthermore, in the tread profile 2S, the radius of curvature r4 of the second portion 22 is desirably 70 mm or more, more desirably 75 mm or more, preferably 100 mm or less, and more desirably 95 mm or less.

[0025] If the difference (r4-r3) between the radius of curvature r3 of the first portion 21 and the radius of curvature r4 of the second portion 22 is excessively large, there is a risk that the steering response and transient characteristics will deteriorate near the outer ground contact position 2e during cornering. For this reason, the difference (r4-r3) is preferably 10.0 mm or more, more preferably 20.0 mm or more, and is preferably 50.0 mm or less, and even more preferably 40.0 mm or less.

[0026] Although not particularly limited, to manufacture such a tire 1, in a mold (not shown) for molding the tread profile 2S, the radius of curvature of the molding surface for molding the first portion 21 is preferably 40 to 60 mm, and the radius of curvature of the molding surface for molding the second portion 22 is preferably 90 to 110 mm. Also, in a mold (not shown) for molding the side profile 3S, the radius of curvature of the molding surface for molding the side profile 3S is preferably 50 to 60 mm. Furthermore, in a mold (not shown) for molding the minor side profile 3T, the radius of curvature of the molding surface for molding the minor side profile 3T is preferably 10 to 15 mm.

[0027] Fig. 2 is a tire meridian cross-sectional view of the tire 1. As shown in Fig. 2, the carcass 6 of this embodiment is formed of one carcass ply 6A. The carcass ply 6A includes, for example, a pair of turned-up portions 6b that are connected to a main body portion 6a and are turned back around the bead cores 5 from the inside to the outside in the tire axial direction and extend in the tire radial direction.

[0028] The tire 1 also includes, in the tread portion 2, a belt layer 7 disposed radially outward of the carcass 6. The belt layer 7 includes at least one belt ply 7A, 7B, which in this embodiment includes two belt plies disposed radially inside and outside the tire. The inner belt ply 7A is adjacent to the carcass 6, for example, radially outward of the tire. Each of the two belt plies 7A, 7B and the carcass ply 6A includes, for example, a cord and a topping rubber (not shown), and is formed of a well-known constituent material.

[0029] The axially outer end 7s of the inner belt ply 7A is located axially more inward than the axially outer end 7t of the outer belt ply 7B. The axial length Lb of the inner belt ply 7A is preferably 75% or more of the tread width TW, more preferably 80% or more, more preferably 90% or less, and even more preferably 85% or less. The tread width TW is the axial length between the tread ends Te.

[0030] The inner liner layer 9 has excellent air barrier properties. The inner liner layer 9 maintains the internal pressure of the tire 1. The inner liner layer 9 is made of a known rubber material. In this embodiment, the inner liner layer 9 extends between the bead toes 4e of each bead portion 4 to form the tire cavity surface 1b. In this specification, the bead toe 4e is the axially innermost point of the tire that contacts the regular rim R.

[0031] Fig. 3 is an enlarged view of the sidewall portion 3 of the tire 1 in Fig. 1. As shown in Fig. 3, the first end 10e of the insulation rubber layer 10 is preferably positioned radially outward of the radially central position c1 of the side profile 3S. Such an insulation rubber layer 10 effectively increases the rigidity of the sidewall portion 3.

[0032] The first end 10e is located, for example, in the tread portion 2. In this embodiment, the first end 10e is located axially inward and radially outward of the outer end 7s of the inner belt ply 7A. This separates the first end 10e from the sidewall portion 3, which experiences relatively large deflection during running, thereby further increasing the sense of rigidity. Although not particularly limited, the axial separation distance Lc between the first end 10e and the outer end 7s of the inner belt ply 7A is preferably 1% or more of the tread width TW, more preferably 5% or more, more preferably 20% or less, and even more preferably 15% or less.

[0033] The insulation rubber layer 10 includes an inner portion 11 and an outer portion 12. The inner portion 11 extends radially inside the bead core 5 in the axial direction. The inner portion 11 is disposed between the main body portion 6a and the inner liner layer 9. This inner portion 11 undergoes compressive deformation during running and applies a tensile force to the cords of the main body portion 6a, thereby increasing the rigidity of the sidewall portion 3 and improving steering stability. Furthermore, this inner portion 11 acts like a damper against loads during running, thereby improving vibration absorption performance. The outer portion 12 is connected to the inner portion 11 and is folded back around the bead core 5 from the inner side in the axial direction to the outer side, extending radially outward. In this embodiment, the outer portion 12 is disposed axially outward of the folded-back portion 6b.

[0034] The length L1 of the inner portion 11 in the tire radial direction is greater than the length L2 of the outer portion 12 in the tire radial direction. As a result, the outer portion 12 prevents an excessive increase in tire rigidity, thereby suppressing vibration during running and maintaining high vibration absorption performance. Furthermore, the region where the inner portion 11 is arranged is farther away from the flange Rf of the normal rim R than the region where the outer portion 12 is arranged, and is therefore an area where large deflection occurs during running. As such, the inner portion 11, which has a relatively large length L2, is arranged in an area where large deflection occurs, so deflection of the tire 1 during running is effectively suppressed and steering stability is improved. In this specification, the length L1 of the inner portion 11 and the length L2 of the outer portion 12 are lengths from the inner end 5i of the bead core 5 in the tire radial direction. In this embodiment, the outer end 11e of the inner portion 11 in the tire radial direction is the first end 10e.

[0035] The outer end 12e of the outer portion 12 is located radially outward of the outermost end t1. The outermost end t1 is the end where the stiffness of the bead portion 4 changes significantly in the tire radial direction. By providing the outer end 12e radially outward of the outermost end t1, the stiffness change of the bead portion 4 can be suppressed, thereby maintaining high vibration absorption. From the viewpoint of achieving both vibration absorption and a sense of stiffness of the tire 1, the radial separation distance Ld between the outer end 12e of the outer portion 12 and the outermost end t1 is, for example, preferably 10.0 mm or more, more preferably 20.0 mm or more, preferably 60.0 mm or less, and more preferably 50.0 mm or less.

[0036] The outer end 12e of the outer portion 12 is located, for example, radially inward of the outer end 6e of the turned-up portion 6b. This causes a radial displacement between the outer end 6e of the turned-up portion 6b and the outer end 12e of the outer portion 12, thereby reducing changes in rigidity of the sidewall portion 3 and reducing deflection during running. In order to achieve both cornering performance and vibration absorption performance, the radial separation distance Le between the outer end 12e of the outer portion 12 and the outer end 6e of the turned-up portion 6b is, for example, desirably 5.0 mm or more, more desirably 10.0 mm or more, desirably 30.0 mm or less, and even more desirably 25.0 mm or less.

[0037] Such an insulation rubber layer 10 is formed from the following rubber composition. The loss tangent tanδ at 70°C is preferably 0.06 or more, more preferably 0.2 or more, and preferably 1.5 or less, and even more preferably 1.0 or less. Because the loss tangent tanδ is 0.06 or more, a high level of vibration absorption effect can be maintained. Because the loss tangent tanδ is 1.5 or less, a decrease in rigidity due to heat generation can be suppressed, and cornering performance can be improved. Furthermore, the rubber hardness at 23°C is preferably 65° or more, more preferably 70° or more, and preferably 85° or less, and even more preferably 80° or less. Because the rubber hardness is 65° or more, the rigidity of the tire 1 is ensured, and cornering performance can be improved. Because the rubber hardness is 85° or less, a high level of vibration absorption effect can be maintained. Furthermore, the breaking elongation at 23°C is preferably 200% or more, and even more preferably 350% or more. Since the breaking elongation is 200% or more, deformation of the sidewall portion 3 and bead portion 4 is suppressed, thereby improving cornering performance. If the breaking elongation is too large, there is a risk that vibration absorption performance will decrease. For this reason, the breaking elongation is preferably 550% or less, and more preferably 500% or less.

[0038] In this specification, the "loss tangent tan δ" is a value measured in accordance with the provisions of JIS-K6394 under the following conditions using a viscoelasticity spectrometer (GABO's "IPLEXER series"). Initial distortion: 10% Amplitude: ±1% Frequency: 10Hz Deformation mode: tension Measurement temperature: 70℃ In this specification, "rubber hardness" refers to a durometer A hardness measured at a standard temperature of 23°C ± 2°C using a durometer type A in accordance with JIS-K6253. Furthermore, in this specification, the "elongation at break" can be measured in accordance with, for example, JIS K6251 "Vulcanized rubber and thermoplastic rubber - Determination of tensile properties".

[0039] FIG. 4 is a tire meridian cross-sectional view of a sidewall portion 3 of another embodiment. As shown in FIG. 4, in this embodiment, a first end 10e of the insulation rubber layer 10 is provided within the side profile 3S. The first end 10e is located, for example, radially inward of a radially intermediate position c1 of the side profile 3S. The radial length L1 of the inner portion 11 is greater than the radial length L2 of the outer portion 12. The radially outer end 12e of the outer portion 12 is located radially inward of the outermost end t1. This insulation rubber layer 10 reduces the mass of the tire 1 and improves cornering performance while maintaining a sense of rigidity.

[0040] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified and implemented in various ways. [Example]

[0041] Motorcycle tires having the basic structure shown in Figure 1 were prototyped based on the specifications in Table 1. Tests were then conducted on the stiffness and vibration absorption of each sample tire. The test method was as follows:

[0042] <Rigidity and vibration absorption> Each test tire was mounted on a 250cc motorcycle under the following conditions. A test rider drove the vehicle on a test course with a dry asphalt surface. The test rider then evaluated each test tire's sense of rigidity related to stability when driving straight ahead, and its ability to absorb vibrations generated when going over gaps, etc. The results are expressed as a score, with Example 1 being given as 10. The higher the score, the better the performance. Tires: 90 / 80R17, 120 / 70R17 (front, rear) Internal pressure: 220kPa, 200kPa (front wheels, rear wheels) The test results are shown in Table 1. In Table 1, L1 in Example 2 and Comparative Example 2 is the same length as L2 in Example 1, and L2 in Example 2 and Comparative Example 2 is the same length as L1 in Example 1.

[0043] [Table 1]

[0044] As shown in Table 1, it can be seen that the tires of the examples have better stiffness and vibration absorption properties and are superior in steering stability performance compared to the tires of the comparative examples.

[0045] [Note] The present invention includes the following aspects.

[0046] [Invention 1] A tire for a motorcycle, a tread portion defining a pair of tread edges; a pair of sidewall portions extending radially inward from the tread portion; a pair of bead portions provided on the radially inner side of the sidewall portions, each of the bead portions having a bead core; a carcass including a carcass ply having a toroidal body portion extending between the pair of bead cores; an inner liner layer disposed on the tire cavity side of the carcass; an insulation rubber layer disposed between the main body portion and the inner liner layer in each of the pair of sidewall portions, Each of the insulation rubber layers extends from a first end on the tread portion side to at least the bead core, In a normal state where the tire is mounted on a normal rim, inflated to a normal internal pressure, and is in an unloaded state, each of the pair of sidewall portions includes an outermost end in the tire radial direction where the normal rim and the tire outer surface of the sidewall portion come into contact, In the tire meridian cross section in the normal state, the tire outer surface of each of the pair of sidewall portions has a side profile that occupies 90% or more of a length in the tire radial direction between the tread edge and the outermost end, The side profile is a straight line or an arc having a curvature radius of 55 mm or more and convex inward in the tire axial direction. Tires for motorcycles. [Invention 2] In the tire meridian cross section in the normal state, the tire outer surface of the tread portion includes a tread profile that is a convex arc shape outward in the tire radial direction, the tread profile includes a first portion extending between a pair of outer contact points that are the outermost contact points in the tire axial direction when the motorcycle tire in the normal state is placed in contact with a flat surface with a normal load applied and tilted at a camber angle of 30 degrees to each side of the pair of tread ends, The motorcycle tire according to Invention 1, wherein the first portion has a radius of curvature of 40 to 60 mm. [Invention 3] the tread profile includes a pair of second portions extending between the pair of outer ground contact locations and the tread edges, The motorcycle tire according to invention 2, wherein the pair of second portions each have a radius of curvature of 70 to 100 mm. [Invention 4] The motorcycle tire according to any one of inventions 1 to 3, wherein the first end is positioned radially outward of a middle position of the side profile in the tire radial direction. [Invention 5] 5. The motorcycle tire according to any one of claims 1 to 4, wherein the first end is located in the tread portion. [Invention 6] The motorcycle tire according to any one of claims 1 to 5, wherein the insulation rubber layer includes an inner portion disposed between the main body portion and the inner liner layer, and an outer portion connected to the inner portion, folded back around the bead core from the inner side in the tire axial direction to the outer side, and extending outward in the tire radial direction. Tires for motorcycles. [Invention 7] 7. A motorcycle tire according to claim 6, wherein the inner portion has a radial length greater than the radial length of the outer portion. [Invention 8] 8. The motorcycle tire according to any one of Inventions 1 to 7, wherein the insulation rubber layer is made of a rubber composition having a loss tangent tan δ at 70° C. of 0.06 to 1.5. [Invention 9] 9. The motorcycle tire according to any one of Inventions 1 to 8, wherein the insulation rubber layer is made of a rubber composition having a rubber hardness at 23°C of 65 to 85°. [Invention 10] 10. The motorcycle tire according to any one of Inventions 1 to 9, wherein the insulation rubber layer is made of a rubber composition having a breaking elongation at 23° C. of 200% or more. [Explanation of symbols]

[0047] 1. Motorcycle tires 2 Tread section 3 Sidewall 1s Tire outer surface 3S Side Profile 5 bead core 6A carcass ply 6a Main body 9 Inner liner layer 10 Insulation rubber layer 10e 1st end R Genuine rim t1 outermost edge Te tread edge

Claims

1. A tire for a motorcycle, a tread portion defining a pair of tread edges; a pair of sidewall portions extending radially inward from the tread portion; a pair of bead portions provided on the radially inner side of the sidewall portions, each of the bead portions having a bead core; a carcass including a carcass ply having a toroidal body portion extending between the pair of bead cores; an inner liner layer disposed on the tire cavity side of the carcass; an insulation rubber layer disposed between the main body portion and the inner liner layer in each of the pair of sidewall portions, Each of the insulation rubber layers extends from a first end on the tread portion side to at least the bead core, In a normal state where the tire is mounted on a normal rim, inflated to a normal internal pressure, and is in an unloaded state, each of the pair of sidewall portions includes an outermost end in the tire radial direction where the normal rim and the tire outer surface of the sidewall portion come into contact, In the tire meridian cross section in a normal state, the tire outer surface of each of the pair of sidewall portions has a side profile that occupies 90% or more of a length in the tire radial direction between the tread edge and the outermost end, The side profile is a straight line or an axially inwardly convex arc with a curvature radius of 55 mm or more. Tires for motorcycles.

2. In the tire meridian cross section in the normal state, the tire outer surface of the tread portion includes a tread profile that is a convex arc shape outward in the tire radial direction, the tread profile includes a first portion extending between a pair of outer contact points that are the outermost contact points in the tire axial direction when the motorcycle tire in the normal state is inclined at a camber angle of 30 degrees to each side of the pair of tread ends and brought into contact with a flat surface under a normal load, 2. The motorcycle tire according to claim 1, wherein the radius of curvature of the first portion is 40 to 60 mm.

3. the tread profile includes a pair of second portions extending between the pair of outer ground contact locations and the tread edges, 3. The motorcycle tire according to claim 2, wherein the radius of curvature of each of the pair of second portions is 70 to 100 mm.

4. The motorcycle tire according to claim 1 , wherein the first end is positioned radially outward of a radially intermediate position of the side profile.

5. The motorcycle tire according to claim 1 , wherein the first end is located in the tread portion.

6. 4. The motorcycle tire according to claim 1, wherein the insulation rubber layer includes an inner portion disposed between the main body portion and the inner liner layer, and an outer portion connected to the inner portion, folded back around the bead core from the inner side in the tire axial direction to the outer side, and extending outward in the tire radial direction. Tires for motorcycles.

7. The motorcycle tire according to claim 6, wherein the inner portion has a radial length greater than the radial length of the outer portion.

8. 4. The motorcycle tire according to claim 1, wherein the insulation rubber layer is made of a rubber composition having a loss tangent tan δ at 70° C. of 0.06 to 1.

5.

9. 4. The motorcycle tire according to claim 1, wherein the insulation rubber layer is made of a rubber composition having a rubber hardness at 23° C. of 65 to 85°.

10. 4. The motorcycle tire according to claim 1, wherein the insulation rubber layer is made of a rubber composition having a breaking elongation at 23[deg.] C. of 200% or more.

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