Motorcycle tires

Abstract

To provide a tire for a motor cycle which further improves transient characteristics and lightness during turning traveling while maintaining off-road performance and uneven wear resistance.SOLUTION: A tire for a motor cycle has a tread part 2. In the tread part 2, a first region S1 which is surrounded by a first inclined main groove 3, a second inclined main groove 4 and a first tread end Te1 and has substantially a triangular shape is partitioned. The first region S1 is partitioned into a plurality of blocks 6 by a plurality of sub-grooves 5. A ratio (A2 / A1) of an area A1 of a block tread 7a of a maximum block 7 to an area A2 of a block tread 8a of a minimum block 8 is 40% to 80%.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] The following Patent Document 1 describes a motorcycle tire having a tread portion provided with first and second inclined main grooves that are inclined in opposite directions and arranged alternately. The tread portion includes a first region surrounded by the first and second inclined main grooves and a first tread edge. The first region includes a plurality of blocks, and each of the blocks includes a contact surface in which the angles of the apexes are all 45 degrees or more. Such a pneumatic tire is said to exhibit excellent resistance to uneven wear while improving on-road and off-road performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-111973 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned tires have room for improvement in terms of transient characteristics and agility during cornering on the road.

[0005] The present invention has been devised in consideration of the above-mentioned circumstances, and has as its main object to provide a motorcycle tire that can further improve the transient characteristics and agility during cornering while maintaining off-road performance and uneven wear resistance. [Means for solving the problem]

[0006] The present invention provides a motorcycle tire having a tread portion, the tread portion including a first tread edge, a second tread edge, and a plurality of first oblique main grooves and a plurality of second oblique main grooves extending therebetween at an inclination in mutually opposite directions with respect to a tire circumferential direction, the plurality of first oblique main grooves and the plurality of second oblique main grooves being alternately arranged in the tire circumferential direction and connected to each other, the tread portion being partitioned into a plurality of substantially triangular first regions surrounded by the first oblique main grooves, the second oblique main grooves, and the first tread edge, the first region being divided into a plurality of blocks by a plurality of sub-grooves, the plurality of blocks including a maximum block having a maximum block tread area and a minimum block having a minimum block tread area, and a ratio (A2 / A1) of a block tread area A1 of the maximum block to a block tread area A2 of the minimum block is 40% to 80%.

[0007] In the motorcycle tire according to the present invention, it is preferable that the sub grooves include a first sub groove extending between the first oblique main groove and the first tread edge, and a second sub groove connected to the first sub groove.

[0008] In the motorcycle tire according to the present invention, it is preferable that a groove width of the second sub groove is smaller than a groove width of the first sub groove.

[0009] In the motorcycle tire according to the present invention, it is preferable that a groove depth of the second sub groove is smaller than a groove depth of the first sub groove.

[0010] In the motorcycle tire according to the present invention, it is preferable that the first minor groove includes a first portion connected to the first oblique main groove and a second portion connected to the first portion and having an angle of inclination with respect to the tire circumferential direction larger than an angle of inclination of the first portion, and a length of the second portion is shorter than a length of the first portion.

[0011] In the motorcycle tire according to the present invention, it is preferable that a length of the second minor groove is greater than a length of the second portion.

[0012] In the motorcycle tire according to the present invention, it is preferable that the first oblique main groove, the second oblique main groove and the first sub groove each have an angle of 40 degrees or more with respect to the circumferential direction of the tire.

[0013] In the motorcycle tire of the present invention, it is preferable that the first inclined main groove includes a first main inclined portion extending across the tire equator and a first sub-inclined portion whose angle with respect to the tire circumferential direction is larger than that of the first main inclined portion and which is located closer to the second tread end than the first main inclined portion, and the second inclined main groove includes a second main inclined portion extending across the tire equator and a second sub-inclined portion whose angle with respect to the tire circumferential direction is larger than that of the second main inclined portion and which is located closer to the first tread end than the second main inclined portion, and the first main inclined portion is connected to the second sub-inclined portion.

[0014] In the motorcycle tire according to the present invention, it is preferable that the second major inclined portion is connected to the first minor inclined portion.

[0015] In the motorcycle tire according to the present invention, it is preferable that the first oblique main groove and the second oblique main groove terminate without communicating with the first tread edge and the second tread edge, respectively.

[0016] In the motorcycle tire according to the present invention, it is preferable that the largest block and the smallest block are adjacent to each other in the tire circumferential direction.

[0017] In the motorcycle tire according to the present invention, the tread portion is partitioned into a plurality of substantially triangular second regions surrounded by the first oblique main groove, the second oblique main groove, and the second tread edge, and the second region is divided into a plurality of blocks by a plurality of sub-grooves, and the plurality of blocks include a maximum block having a maximum block tread area and a minimum block having a minimum block tread area, and it is preferable that a ratio (A2' / A1') of a block tread area A1' of the maximum block to a block tread area A2' of the minimum block is 40% to 80%. Effect of the Invention

[0018] By employing the above-described configuration, the motorcycle tire of the present invention can further improve the transient characteristics and agility during cornering while maintaining off-road performance and uneven wear resistance. [Brief description of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view of a motorcycle tire showing one embodiment of the present invention. [Diagram 2] FIG. 2 is a developed plan view of the tread portion of FIG. [Diagram 3] FIG. 3 is an enlarged view of a first region of FIG. [Figure 4] FIG. 3 is an enlarged view of a first region of FIG. [Diagram 5] FIG. 2 is a developed plan view of the tread portion of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a motorcycle tire 1 (hereinafter, sometimes simply referred to as "tire") in a normal state, showing one embodiment of the present invention. FIG. 2 is a plan view of a tread portion 2 of the tire 1 developed. The tire 1 of this embodiment is suitable for traveling on a course that is a mixture of on-road and off-road. The tire 1 of this embodiment is used, for example, on the rear wheel of a motorcycle. The tire 1 may also be used on the front wheel of a motorcycle. FIG. 1 is a cross-sectional view taken along line AA of FIG. 2.

[0021] The "normal state" refers to a state in which the tire 1 is mounted on a normal rim (not shown), inflated to normal internal pressure, and no load is applied. Unless otherwise specified in this specification, the dimensions of each part of the tire 1 are values ​​measured in the normal state.

[0022] A "genuine rim" is a rim that is defined 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 a "standard rim," in the case of TRA, it is called a "Design Rim," and in the case of ETRTO, it is called a "Measuring Rim."

[0023] "Normal internal pressure" is the air pressure set for each tire by each standard in the standard system on which the tire is based. In the case of JATMA, it is the "maximum air pressure." In the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." In the case of ETRTO, it is the "INFLATION PRESSURE."

[0024] 1, in the tire 1 of this embodiment, in the normal state, the outer surface 2s of the tread portion 2 is curved in a circular arc convex outward in the tire radial direction. Such a tire 1 can obtain a sufficient contact area even during cornering with a large camber angle.

[0025] The tread portion 2 has a first tread end Te1 (on the right side in the figure) and a second tread end Te2 (on the left side in the figure). The first tread end Te1 and the second tread end Te2 correspond to both ends of the tread portion 2 in the tire axial direction, and may come into contact with the ground when turning near the maximum camber angle, for example.

[0026] As shown in FIG. 2, the tread portion 2 includes a plurality of first oblique main grooves 3 and a plurality of second oblique main grooves 4 extending between a first tread end Te1 and a second tread end Te2 at an inclination in mutually opposite directions with respect to the tire circumferential direction.

[0027] The first oblique main grooves 3 and the second oblique main grooves 4 are alternately arranged in the tire circumferential direction and connected to each other, thereby defining a plurality of substantially triangular first regions S1 in the tread portion 2, each of which is surrounded by the first oblique main grooves 3, the second oblique main grooves 4, and the first tread edge Te1.

[0028] The first region S1 is divided into a plurality of blocks 6 by a plurality of sub-grooves 5. It is preferable that the first region S1 is provided with, for example, 4 to 8 blocks 6. The plurality of blocks 6 includes a maximum block 7 having a maximum area of ​​the block tread surface 7a and a minimum block 8 having a minimum area of ​​the block tread surface 8a.

[0029] The ratio (A2 / A1) between the area A1 of the block tread 7a of the largest block 7 and the area A2 of the block tread 8a of the smallest block 8 is 40% to 80%. Since the ratio (A2 / A1) is 40% or more, the rigidity difference between the blocks 6 in the first region S1 is small. This improves the transient characteristics and agility from the early stage to the later stage of on-road cornering. In addition, since the block rigidity difference is small in the first region S1, uneven wear resistance is maintained. Furthermore, since the ratio (A2 / A1) is 80% or less, unbalanced deformation occurs in the first region S1 when the blocks 6 contact the ground, and the mud discharge action in the first inclined main groove 3, the second inclined main groove 4, and the sub-groove 5 is enhanced, and the off-road performance is also improved. In this specification, the "transient characteristics" refers to the smoothness of the leaning of the vehicle body from the early stage to the later stage of cornering. "Nimbleness" refers to the responsiveness of the vehicle when the rider intentionally changes the camber angle. Furthermore, the transient characteristics and nimbleness of cornering on the road are sometimes referred to as "on-road performance."

[0030] In this embodiment, the tread portion 2 has a fixed tire rotation direction R. However, the tread portion 2 of the present invention is not limited to one having a fixed tire rotation direction R.

[0031] The first oblique main groove 3 terminates without communicating with the first tread end Te1 and the second tread end Te2 (hereinafter, these are simply referred to as "tread ends Te"). Similarly, the second oblique main groove 4 terminates without communicating with both tread ends Te. Such first oblique main groove 3 and second oblique main groove 4 suppress the decrease in rigidity of the tread end Te where a large lateral force acts, thereby improving on-road performance. Although not particularly limited, the distance La in the tire axial direction between each tread end Te and the first end 3e of the first oblique main groove 3 or the first end 4e of the second oblique main groove 4 is preferably 1 mm or more, more preferably 2 mm or more, more preferably 5 mm or less, and more preferably 4 mm or less. The first ends 3e and 4e are called ends that are not connected to other grooves and are interrupted at the outer surface 2s of the tread portion 2.

[0032] The first oblique main groove 3 includes a first main inclined portion 3A extending across the tire equator C, and a first sub inclined portion 3B inclined at an angle θ1 greater than the angle of the first main inclined portion 3A with respect to the tire circumferential direction and disposed closer to the second tread edge Te2 than the first main inclined portion 3A. In this embodiment, the first main inclined portion 3A and the first sub inclined portion 3B are connected to one side in the tire circumferential direction (the upper side in the figure) via a bent portion K1 that is convex.

[0033] The second oblique main groove 4 includes a second main inclined portion 4A extending across the tire equator C, and a second sub inclined portion 4B inclined at an angle θ3 greater than the angle of the second main inclined portion 4A with respect to the tire circumferential direction and disposed closer to the first tread edge Te1 than the second main inclined portion 4A. In this embodiment, the second main inclined portion 4A and the second sub inclined portion 4B are connected to one side in the tire circumferential direction (the upper side in the figure) via a bent portion K2 that is convex.

[0034] The first main inclined portion 3A is connected to the second sub inclined portion 4B. The second main inclined portion 4A is connected to the first sub inclined portion 3B. This ensures a large tire axial length L1 of the first and second inclined main grooves 3 and 4, thereby increasing the shear force against mud. This results in excellent off-road performance. The first main inclined portion 3A of this embodiment is not connected to the bent portion K2 of the second inclined main groove 4, but is connected to the second sub inclined portion 4B on the first tread edge Te1 side of the bent portion K2. The second main inclined portion 4A of this embodiment is not connected to the bent portion K1 of the first inclined main groove 3, but is connected to the first sub inclined portion 3B on the second tread edge Te2 side of the bent portion K1.

[0035] Although not particularly limited, the angle θ1 of the first main inclined portion 3A and the angle θ3 of the second main inclined portion 4A are preferably 30 degrees or more, more preferably 40 degrees or more, and more preferably 60 degrees or less, and more preferably 50 degrees or less. In addition, the angle θ2 of the first minor inclined portion 3B with respect to the tire circumferential direction and the angle θ4 of the second minor inclined portion 4B with respect to the tire circumferential direction are preferably 35 degrees or more, more preferably 45 degrees or more, and more preferably 65 degrees or less, and more preferably 55 degrees or less.

[0036] Fig. 3 is an enlarged view of the first region S1 in Fig. 2. As shown in Fig. 3, the sub groove 5 extends, for example, at an angle to the tire circumferential direction. Since such a sub groove 5 has an axial component, it exerts a shear force against mud and improves off-road performance.

[0037] The sub groove 5 includes a first sub groove 11 extending between the first oblique main groove 3 and the first tread edge Te1, and a second sub groove 12 connected to the first sub groove 11. For example, the outer end 11e of the first sub groove 11 on the first tread edge Te1 side terminates within the tread portion 2 without connecting to the first tread edge Te1. Both ends of the second sub groove 12 are connected to the groove. In this specification, the "groove" refers to a groove-shaped body having a groove width of 1.5 mm or more.

[0038] The distance Lb in the tire axial direction between the outer end 11e of the first minor groove 11 and the first tread edge Te1 is preferably the same as the distance La. For example, the distance Lb is preferably 1 mm or more, more preferably 2 mm or more, and is preferably 5 mm or less, and more preferably 4 mm or less.

[0039] The first sub groove 11 includes a first portion 11A connected to the first oblique main groove 3, and a second portion 11B connected to the first portion 11A and having an angle θ6 larger than the angle θ5 of inclination of the first portion 11A with respect to the tire circumferential direction. Such a first sub groove 11 maintains high rigidity in the tire axial direction near the first tread end Te1 where the lateral force acts. The first portion 11A and the second portion 11B are connected via a bent portion K3 that is convex toward one side in the tire circumferential direction. The difference (θ6-θ5) between the angle θ5 of the first portion 11A and the angle θ6 of the second portion 11B is preferably 20 degrees or more, more preferably 25 degrees or more, more preferably 50 degrees or less, and even more preferably 45 degrees or less.

[0040] In this embodiment, the first sub groove 11 includes a first short sub groove 13 having a smaller length in the tire axial direction, and a first long sub groove 14 having a larger length in the tire axial direction than the first short sub groove 13. In this embodiment, the first long sub groove 14 is disposed closer to the second inclined main groove 4 than the first short sub groove 13. The first portion 11A of the first long sub groove 14 is inclined at an angle closer to the angle θ3 of the second main inclined portion 4A than the first portion 11A of the first short sub groove 13.

[0041] The first portion 11A extends along the second main inclined portion 4A of the second inclined main groove 4. This reduces the difference in rigidity between the block 6 divided by the first portion 11A and the second main inclined portion 4A, and between the block 6 divided between the first portions 11A, in a direction perpendicular to the first portion 11A, thereby improving uneven wear resistance. In this specification, the term "extending along" refers to a state in which the absolute value of the difference between the angle θ5 of the first portion 11A and the angle θ3 (shown in FIG. 2) of the second main inclined portion 4A is 20 degrees or less.

[0042] The length Ld of the second portion 11B is formed to be smaller than the length Lc of the first portion 11A. This maintains the traction performance, and the mud in the first portion 11A is smoothly discharged to the rear side in the tire rotation direction R by utilizing the rotation of the tire 1. Although not particularly limited, the length Ld of the second portion 11B is preferably 35% or more of the tread development half width TWh (shown in FIG. 2), more preferably 40% or more, more preferably 55% or less, and even more preferably 50% or less. The tread development half width TWh is the length along the outer surface 2s of the tread portion 2 from the tire equator C to each tread end Te. In addition, each length of the sub-groove 5 is the length at the groove center line of each sub-groove 5.

[0043] 4 is an enlarged view of the first region S1 in FIG. 2. As shown in FIG. 4, the groove width W2 of the first sub groove 11 is preferably 80% or more of the groove width W1 of the first oblique main groove 3 and the second oblique main groove 4, more preferably 90% or more, more preferably 120% or less, and more preferably 110% or less. In this embodiment, the groove width W2 of the first sub groove 11 is the same as the groove width W1 of the first oblique main groove 3. The groove width W2 of the first sub groove 11 is preferably 10% or more of the tread development half width TWh, more preferably 15% or more, more preferably 30% or less, and more preferably 25% or less.

[0044] The second sub groove 12 extends, for example, linearly. Such a second sub groove 12 suppresses uneven wear occurring in each block 6.

[0045] The second sub groove 12 includes, for example, a main groove-side second sub groove 17 connecting the first long sub groove 14 and the second oblique main groove 4, and a sub groove-side second sub groove 18 connecting the first long sub groove 14 and the first short sub groove 13. The main groove-side second sub groove 17 includes, for example, an outer second sub groove 19 located on the first tread edge Te1 side, and an inner second sub groove 20 located axially inward of the outer second sub groove 19 (on the second tread edge Te2 side).

[0046] As a result, six blocks 6 are formed in the first region S1. Three blocks 6 are formed between the second oblique main groove 4 and the first long sub-groove 14. Two blocks 6 are formed between the first long sub-groove 14 and the first short sub-groove 13. One block 6 is formed between the first short sub-groove 13, the first oblique main groove 3, and the first tread edge Te1.

[0047] The largest block 7 of this embodiment is divided by the first long sub-groove 14, the first short sub-groove 13, the sub-groove side second sub-groove 18, and the first tread edge Te1. The smallest block 8 of this embodiment is divided by the second inclined main groove 4, the first long sub-groove 14, the outer second sub-groove 19, and the first tread edge Te1. When the first inclined main groove 3, the second inclined main groove 4, and the first sub-groove 11 are not connected to the first tread edge Te1 as in this embodiment, the area of ​​the block tread 6a is defined as follows. The area of ​​the block tread 6a is defined by the area of ​​a virtual block tread 6v formed including a virtual groove edge e obtained by extending the groove edge extending in the longitudinal direction of each groove to the first tread edge Te1 in the portion not connected to the first tread edge Te1. In FIG. 4, the virtual block tread 6v is indicated by hatching.

[0048] In this embodiment, the largest block 7 and the smallest block 8 are adjacent to each other in the tire circumferential direction. In this manner, the largest block 7 having the maximum block rigidity and the smallest block 8 having the minimum block rigidity are adjacent to each other in the tire circumferential direction, so that the largest block 7 and the smallest block 8 undergo large unbalanced deformations when coming into contact with the ground, thereby achieving high off-road performance.

[0049] The length Le of the second sub groove 12 is greater than the length Ld (shown in FIG. 3) of the second portion 11B. Such second sub grooves 12 maintain high rigidity in the tire circumferential direction of the blocks 6 formed by the second sub grooves 12, improving uneven wear resistance. In this embodiment, the length Le of all the second sub grooves 12 is greater than the length Ld of the second portion 11B.

[0050] The groove width W3 of the second sub groove 12 is, for example, smaller than the groove width W2 of the first sub groove 11. Such a second sub groove 12 maintains block rigidity and improves uneven wear resistance. The groove width W3 of the second sub groove 12 is preferably 30% or more of the groove width W2 of the first sub groove 11, more preferably 40% or more, more preferably 80% or less, and even more preferably 70% or less.

[0051] The angle θ7 of the second sub groove 12 with respect to the tire circumferential direction is formed to be smaller than the angle θ5 (shown in FIG. 3) of the first portion 11A of the first sub groove 11, for example. Since such a second sub groove 12 can utilize the rolling of the tire 1, the reduction in mud discharge action due to the narrowing of the groove width is suppressed, and the reduction in rigidity of the block 6 adjacent to the second sub groove 12 is suppressed, thereby improving the uneven wear resistance. From this viewpoint, the difference (θ5-θ7) between the angle θ5 of the first portion 11A and the angle θ7 of the second sub groove 12 is preferably 5 degrees or more, more preferably 10 degrees or more, more preferably 25 degrees or less, and more preferably 20 degrees or less. The angle θ7 of the second sub groove 12 is preferably 5 degrees or more, more preferably 10 degrees or more, more preferably 20 degrees or less, and more preferably 15 degrees or less.

[0052] As shown in FIG. 1, the groove depth d3 of the second sub groove 12 is preferably smaller than the groove depth d2 of the first sub groove 11. This allows the above-mentioned effects to be effectively achieved. The groove depth d3 of the second sub groove 12 is preferably 2 mm or more and 4 mm or less. The groove depth d2 of the first sub groove 11 is preferably 3 mm or more and 6 mm or less. The groove depth d1 of the first inclined main groove 3 and the second inclined main groove 4 is preferably larger than the groove depth d3 of the second sub groove 12, for example, preferably 3 mm or more and 6 mm or less.

[0053] Fig. 5 is a developed plan view of the tread portion 2 of the present embodiment. As shown in Fig. 5, the tread portion 2 is partitioned into a plurality of second regions S2 each having a substantially triangular shape surrounded by the first oblique main grooves 3, the second oblique main grooves 4, and the second tread edge Te2. The second region S2 is partitioned into a plurality of blocks 6 by a plurality of sub grooves 5.

[0054] The sub groove 5 of the second region S2 includes a third sub groove 23 extending between the second oblique main groove 4 and the second tread edge Te2, and a fourth sub groove 24 connected to the third sub groove 23. The third sub groove 23 of this embodiment has the same shape as the first sub groove 11 of this embodiment, so a detailed description thereof is omitted. The fourth sub groove 24 of this embodiment has the same shape as the second sub groove 12 of this embodiment, so a detailed description thereof is omitted.

[0055] Moreover, the blocks 6 in the second region S2 formed by such third sub-groove 23 and fourth sub-groove 24 are formed in the same shape as the blocks 6 formed in the first region S1. The blocks 6 include a maximum block 9 having a maximum area of ​​the block tread 9a and a minimum block 10 having a minimum area of ​​the block tread 10a. The ratio (A2' / A1') between the area A1' of the block tread 9a of the maximum block 9 and the area A2' of the block tread 10a of the minimum block 10 is preferably 40% to 80%. In this embodiment, the maximum block 9 has the same shape as the maximum block 7 in the first region S1. In this embodiment, the minimum block 10 has the same shape as the minimum block 8 in the first region S1.

[0056] The angles α1, α2, α3 of the first oblique main groove 3, the second oblique main groove 4, and the first sub groove 11 with respect to the tire circumferential direction are preferably 40 degrees or more. Such grooves 3, 4, 11 provide high traction. These angles α1, α2, α3 are defined by a virtual straight line P connecting both ends of the groove center lines of the grooves 3, 4, 11, respectively.

[0057] Although the motorcycle tire according to one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-mentioned specific embodiment and can be modified and carried out in various aspects. EXAMPLES

[0058] Motorcycle tires having the basic structure shown in Fig. 1 and the tread pattern shown in Fig. 2 were prototyped based on the specifications in Table 1. Each test tire was then tested for on-road performance, off-road performance, and uneven wear resistance.

[0059] <On-road performance, off-road performance, resistance to uneven wear> The test tires were mounted on the following test vehicle, and a test rider drove the vehicle on a test course with dry asphalt and muddy road surfaces. The on-road performance was evaluated by the test rider's senses in terms of transient characteristics and agility when driving on dry asphalt road surfaces. The off-road performance was evaluated by the test rider's senses in terms of traction when driving on muddy road surfaces and driving stability when turning. The uneven wear resistance performance was evaluated by the test rider's visual inspection of the occurrence of uneven wear after the on-road performance test. All results are shown on a 10-point scale with 10 being the maximum score. Test vehicle: 500cc motorcycle Tire size (front and rear): 120 / 70R17, 160 / 60R17 Rim size (front and rear): 3.50 x 17, 4.50 x 17 Tire pressure (all wheels): 250kPa The test results are shown in Table 1.

[0060] [Table 1]

[0061] As a result of the tests, it can be seen that the tires of the examples have improved transient characteristics and agility during cornering while maintaining off-road performance and resistance to uneven wear compared to the tires of the comparative examples.

[0062] 1. Motorcycle tires 2 Tread section 3 1st inclined main groove 4 2nd inclined main groove 5. Minor Groove 6 Blocks 7 Largest Block 7a Block tread 8. Smallest Block 8a Block tread S1 1st area Te1 First tread edge

Claims

1. A motorcycle tire having a tread portion, The tread portion includes a first tread edge, a second tread edge, and a plurality of first oblique main grooves and a plurality of second oblique main grooves extending therebetween at an inclination in mutually opposite directions with respect to a tire circumferential direction, the first oblique main grooves and the second oblique main grooves are alternately arranged in the tire circumferential direction and are connected to each other; The tread portion is partitioned into a plurality of substantially triangular first regions each surrounded by the first oblique main groove, the second oblique main groove, and the first tread edge, the first region is divided into a plurality of blocks by a plurality of minor grooves, The plurality of blocks include a maximum block having a maximum area of ​​a block tread surface and a minimum block having a minimum area of ​​a block tread surface, a ratio (A2 / A1) of an area A1 of the block tread surface of the largest block to an area A2 of the block tread surface of the smallest block is 40% to 80%; the largest block and the smallest block are adjacent to each other in the tire circumferential direction, the maximum block and the minimum block are adjacent to the first tread edge, Tires for motorcycles.

2. 2. The motorcycle tire according to claim 1, wherein the sub groove includes a first sub groove extending between the first oblique main groove and the first tread edge, and a second sub groove connected to the first sub groove.

3. The motorcycle tire according to claim 2 , wherein a groove width of the second sub groove is smaller than a groove width of the first sub groove.

4. The motorcycle tire according to claim 2 or 3, wherein a groove depth of the second sub groove is smaller than a groove depth of the first sub groove.

5. the first sub groove includes a first portion connected to the first oblique main groove, and a second portion connected to the first portion and having an angle of inclination with respect to the tire circumferential direction that is greater than an angle of inclination of the first portion, The motorcycle tire according to claim 2 , wherein a length of the second portion is smaller than a length of the first portion.

6. The motorcycle tire according to claim 5 , wherein a length of the second minor groove is greater than a length of the second portion.

7. The motorcycle tire according to claim 2 , wherein the first main inclined groove, the second main inclined groove and the first sub-groove each have an angle of 40 degrees or more with respect to the circumferential direction of the tire.

8. the first oblique main groove includes a first main inclined portion extending across the tire equator, and a first sub-inclined portion inclined at an angle greater than an angle of the first main inclined portion with respect to the tire circumferential direction and disposed closer to the second tread edge than the first main inclined portion, the second inclined main groove includes a second main inclined portion extending across the tire equator, and a second sub-inclined portion inclined at an angle greater than an angle of the second main inclined portion with respect to the tire circumferential direction and disposed closer to the first tread edge than the second main inclined portion, The motorcycle tire according to claim 1 , wherein the first major inclined portion is connected to the second minor inclined portion.

9. The motorcycle tire according to claim 8 , wherein the second major inclined portion is connected to the first minor inclined portion.

10. The motorcycle tire according to claim 1 , wherein the first oblique main groove and the second oblique main groove terminate without communicating with the first tread edge and the second tread edge, respectively.

11. The tread portion is partitioned into a plurality of substantially triangular second regions surrounded by the first inclined main groove, the second inclined main groove, and the second tread edge, the second region is divided into a plurality of blocks by a plurality of minor grooves, The plurality of blocks include a maximum block having a maximum area of ​​a block tread surface and a minimum block having a minimum area of ​​a block tread surface, The motorcycle tire according to any one of claims 1 to 10, wherein a ratio (A2' / A1') of a block tread area A1' of the largest block to a block tread area A2' of the smallest block is 40% to 80%.

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