Motorcycle tires

Abstract

Provided is a motorcycle tire that can simultaneously achieve grip performance during rolling, transient characteristics, and uneven wear resistance. [Solution] The present invention provides a motorcycle tire (1) for rough terrain use, having a tread portion (2). The tread portion (2) includes first blocks (5) and second blocks (6) protruding from a groove bottom (3). The first blocks (5) have a first ground-contact surface (5a) and a first side surface (5c) extending from a first ground-contact edge (5b) of the first ground-contact surface (5a) to the groove bottom (3). The second blocks (6) have a second ground-contact surface (6a) and a second side surface (6c) extending from a second ground-contact edge (6b) of the second ground-contact surface (6a) to the groove bottom (3). The first and second ground-contact surfaces (5a, 5b) form the same profile plane (Ps). The first and second side surfaces (5c, 6c) intersect at a virtual intersection (P) on a projection plane (S). A first distance (L1) from the virtual intersection (P) to the first ground-contact edge (5b) is greater than a second distance (L2) from the virtual intersection (P) to the second ground-contact edge (6b).

Description

[Technical Field]

[0001] The present invention relates to a motorcycle tire having a tread portion for use on rough terrain. [Background technology]

[0002] Conventionally, motorcycle tires for rough terrain that have a tread portion have been known. For example, Patent Document 1 below proposes a motorcycle tire for rough terrain that has an inner edge of a shoulder block protruding from a virtual tread surface to improve grip performance during cornering. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-013727 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the motorcycle tire of Patent Document 1, a portion of the block protrudes radially outward from the profile surface, leaving room for improvement in transient characteristics during rolling. In addition, the high ground contact pressure in the protruding portion can lead to uneven wear.

[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 simultaneously achieve grip performance during rolling, transient characteristics, and uneven wear resistance. [Means for solving the problem]

[0006] The present invention provides a motorcycle tire for rough terrain use having a tread portion, the tread portion comprising a plurality of blocks protruding from a groove bottom surface, the plurality of blocks including first blocks and second blocks positioned axially inward of the first blocks, the first blocks having a first contact surface that comes into contact with the road surface during running, and a first side surface that extends radially inward from a first contact edge of the first contact surface that is axially inward of the tire to the groove bottom surface, the second blocks having a second contact surface that comes into contact with the road surface during running, and a first side surface that extends radially inward from a first contact edge of the first contact surface that is axially inward of the tire to the groove bottom surface, the second blocks having a second contact surface that comes into contact with the road surface during running, and a first side surface that extends radially inward from the ... edge. The tire has a second side surface extending from a second ground contact edge on the outer side of the tire axial direction of the ground to the inner side in the tire radial direction and reaching the groove bottom surface, the first ground contact surface and the second ground contact surface forming the same profile surface, the first side surface and the second side surface intersect at a virtual intersection point on a projection surface projected onto a common tire meridian cross section along the tire circumferential direction, and a first distance along the first side surface from the virtual intersection point to the first ground contact edge is greater than a second distance along the second side surface from the virtual intersection point to the second ground contact edge. [Effects of the Invention]

[0007] The motorcycle tire of the present invention has the above-described configuration, and thus can simultaneously achieve grip performance during rolling, transient characteristics, and uneven wear resistance. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a development view showing an embodiment of a tire for a motorcycle according to the present invention. [Figure 2] FIG. 2 is a tire meridian cross-sectional view showing a projection plane. [Figure 3] FIG. 3 is an enlarged view of part A in FIG. 2. [Figure 4] FIG. 2 is a cross-sectional view taken along the line BB in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a development view showing a tread portion 2 of a motorcycle tire 1 of this embodiment. As shown in Fig. 1, the motorcycle tire 1 of this embodiment has a tread portion 2 with a plurality of blocks 4 protruding from a groove bottom surface 3. Such a motorcycle tire 1 is suitable for use as a motorcycle tire 1 for traveling on rough terrain.

[0010] The plurality of blocks 4 in this embodiment include first blocks 5 and second blocks 6 that are located axially inward of the first blocks 5. The first blocks 5 and the second blocks 6 cooperate with each other to improve the grip performance of the motorcycle tire 1 on rough terrain.

[0011] The first block 5 of this embodiment has a first contact surface 5a that comes into contact with the road surface during driving, and a first side surface 5c that extends from a first contact end 5b on the inner side of the first contact surface 5a in the tire axial direction to the inner side in the tire radial direction and reaches the groove bottom surface 3.

[0012] The second block 6 of this embodiment has a second contact surface 6a that comes into contact with the road surface during driving, and a second side surface 6c that extends from a second contact end 6b on the outer side of the second contact surface 6a in the tire axial direction to the inner side in the tire radial direction and reaches the groove bottom surface 3.

[0013] 2 is a tire meridian cross-sectional view showing a projection plane S obtained by projecting the first side surface 5c and the second side surface 6c onto a common tire meridian cross-section along the tire circumferential direction. As shown in FIG. 2, it is desirable that the first contact patch 5a and the second contact patch 6a mutually constitute the same profile plane Ps.

[0014] Such first and second contact surfaces 5a and 6a have no portions that protrude from the profile surface Ps, and can improve the transient characteristics during rolling of the motorcycle tire 1. Furthermore, such tread portion 2 has no portions that protrude from the profile surface Ps, and can suppress uneven wear, thereby improving the uneven wear resistance of the motorcycle tire 1.

[0015] Fig. 3 is an enlarged view of part A in Fig. 2. As shown in Fig. 2 and Fig. 3, on the projection plane S, the first side surface 5c and the second side surface 6c of this embodiment intersect at a virtual intersection point P. In this embodiment, a first distance L1 along the first side surface 5c from the virtual intersection point P to the first grounding end 5b is greater than a second distance L2 along the second side surface 6c from the virtual intersection point P to the second grounding end 6b.

[0016] In such a tread portion 2, when a load is applied during rolling, the first blocks 5 and the second blocks 6 deform so that the ground contact pressure of the first ground contact surface 5a becomes greater than the ground contact pressure of the second ground contact surface 6a, thereby improving the grip performance of the motorcycle tire 1. Therefore, the motorcycle tire 1 of this embodiment can simultaneously achieve grip performance during rolling, transient characteristics, and uneven wear resistance.

[0017] In a more preferred embodiment, on the projection plane S, the first side surface 5c includes at least one bend 5d, at which the angle with respect to the tire radial direction changes, between the first ground-contacting edge 5b and the virtual intersection P. Such a first side surface 5c can increase the first distance L1 without excessively increasing the angle θ1 with the first ground-contacting surface 5a, which helps to improve the grip performance of the motorcycle tire 1 during rolling.

[0018] On the projection plane S, the angle θ1 formed between the first ground contact surface 5a and the first side surface 5c at the first ground contact end 5b is preferably 80 to 100°. When the angle θ1 formed between the first ground contact surface 5a and the first side surface 5c is 80° or more, it is possible to suppress the occurrence of chipping at the first ground contact end 5b, and it is possible to improve the durability performance of the motorcycle tire 1.

[0019] By setting the angle θ1 between the first ground contact surface 5a and the first side surface 5c to 100° or less, the edge effect of the first ground contact end 5b can be exerted, and the grip performance during rolling of the motorcycle tire 1 can be improved. From this perspective, the angle θ1 between the first ground contact surface 5a and the first side surface 5c at the first ground contact end 5b is more preferably 85 to 95°.

[0020] On the projection plane S, it is desirable that the angle θ2 formed between the second ground contact surface 6a and the second side surface 6c at the second ground contact end 6b be larger than the angle θ1 formed between the first ground contact surface 5a and the first side surface 5c at the first ground contact end 5b. Such a second block 6 helps to make the ground contact pressure of the first ground contact surface 5a greater than the ground contact pressure of the second ground contact surface 6a when a load is applied during rolling.

[0021] On the projection plane S, the angle θ2 formed between the second ground contact surface 6a and the second side surface 6c at the second ground contact end 6b is preferably 90 to 110°. When the angle θ2 formed between the second ground contact surface 6a and the second side surface 6c is 90° or more, it is possible to suppress the occurrence of chipping at the second ground contact end 6b, and it is possible to improve the durability performance of the motorcycle tire 1.

[0022] By setting the angle θ2 between the second ground contact surface 6a and the second side surface 6c to 110° or less, it is possible to reduce the second distance L2 and improve the grip performance during rolling of the motorcycle tire 1. From this perspective, the angle θ2 between the second ground contact surface 6a and the second side surface 6c at the second ground contact end 6b is more preferably 95 to 105°.

[0023] On the projection plane S, the difference (L1-L2) between the first distance L1 and the second distance L2 is preferably 5 mm or less. By keeping the difference (L1-L2) between the first distance L1 and the second distance L2 at 5 mm or less, it is possible to prevent the ground contact pressure acting on the first ground contact end 5b from becoming excessively large and to suppress uneven wear of the first ground contact surface 5a. From this perspective, the difference (L1-L2) between the first distance L1 and the second distance L2 is more preferably 3 mm or less.

[0024] On the projection plane S, the shortest distance L3 from the profile surface Ps to the virtual intersection P is preferably 70% or more of the first block height H1 from the groove bottom surface 3 to the first ground-contacting edge 5b. By making the shortest distance L3 from the profile surface Ps to the virtual intersection P 70% or more of the first block height H1, the first ground-contacting edge 5b can be reliably brought into contact with the ground during rolling, which helps to improve the grip performance of the motorcycle tire 1 during rolling. From this perspective, the shortest distance L3 from the profile surface Ps to the virtual intersection P is more preferably 80% or more of the first block height H1.

[0025] In the projection plane S, the second block height H2 from the groove bottom surface 3 to the second ground-contact edge 6b in this embodiment is equal to the first block height H1. Here, in this specification, "equal dimensions" means that the difference between the dimensions is within 5% of the larger dimension. Such a tread portion 2 helps to suppress the occurrence of uneven wear during rolling and improve the uneven wear resistance of the motorcycle tire 1.

[0026] Fig. 4 is a tire meridian cross-sectional view of the normal state taken along line BB in Fig. 1. Here, the "normal state" refers to a state in which the motorcycle tire 1 is mounted on a normal rim, and is adjusted to a normal internal pressure and is unloaded. Unless otherwise specified below, the dimensions of each part of the motorcycle tire 1 are values ​​measured in this normal state.

[0027] A "genuine rim" is a rim that is defined for each tire by a standard system that includes the standard on which motorcycle tire 1 is based, and is, for example, a "standard rim" for JATMA, a "design rim" for TRA, and a "measuring rim" for ETRTO.

[0028] "Normal internal pressure" is the air pressure set for each tire by the standard system including the standard on which motorcycle tire 1 is based, and is the "maximum air pressure" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and the "INFLATION PRESSURE" in the case of ETRTO.

[0029] As shown in Figures 1 and 4, the blocks 4 in this embodiment include shoulder blocks 7, middle blocks 8, and crown blocks 9. The shoulder blocks 7 are, for example, the axially outermost blocks that form the tread edges Te. The tread edges Te are the axially outermost edges that come into contact with the ground when the camber angle is maximized due to rolling. The axial center between the tread edges Te is the tire equator C.

[0030] The shoulder block 7 includes, for example, a shoulder first portion 7A and shoulder second portions 7B located on both sides of the shoulder first portion 7A in the tire circumferential direction. The height of the shoulder first portion 7A from the groove bottom surface 3 is desirably greater than the height of the shoulder second portion 7B from the groove bottom surface 3. Such a shoulder block 7 can exert an edge effect with the shoulder first portion 7A and the shoulder second portion 7B, thereby improving the grip performance of the motorcycle tire 1.

[0031] The middle blocks 8 are, for example, adjacent to the shoulder blocks 7 on the inner side in the tire axial direction, and are located between the shoulder blocks 7 and the crown blocks 9 in the tire axial direction.

[0032] The middle block 8 includes, for example, a first middle portion 8A and second middle portions 8B located on both sides of the first middle portion 8A in the tire circumferential direction. The height of the first middle portion 8A from the groove bottom surface 3 is preferably greater than the height of the second middle portion 8B from the groove bottom surface 3. Such a middle block 8 can exhibit an edge effect with the first middle portion 8A and the second middle portion 8B, thereby improving the grip performance of the motorcycle tire 1.

[0033] The first blocks 5 in this embodiment are the first shoulder portions 7A of the shoulder blocks 7. In this case, the second blocks 6 are the first middle portions 8A of the middle blocks 8. Such a motorcycle tire 1 can simultaneously achieve grip performance, transient characteristics, and uneven wear resistance when the camber angle due to rolling is large.

[0034] The first blocks 5 may be, for example, second shoulder portions 7B of the shoulder blocks 7. In this case, the second blocks 6 are second middle portions 8B of the middle blocks 8. That is, the first blocks 5 in this embodiment are shoulder blocks 7, and the second blocks 6 in this case are middle blocks 8. Such a motorcycle tire 1 can simultaneously achieve a higher level of grip performance, transient characteristics, and uneven wear resistance when the camber angle due to rolling is large.

[0035] The shoulder blocks 7 and the middle blocks 8 are preferably connected by tie bars 10. In this embodiment, the shoulder second portions 7B and the middle second portions 8B are connected by tie bars 10. Such a tread portion 2 suppresses excessive deformation of the shoulder blocks 7 and the middle blocks 8, and helps to achieve both transient characteristics during rolling of the motorcycle tire 1 and uneven wear resistance.

[0036] The crown blocks 9 are, for example, adjacent to the middle blocks 8 on the axially inner side and located on the tire equator C. The crown blocks 9 preferably have crown narrow grooves 9a extending on the tire equator C. Such crown blocks 9 are useful for improving the grip performance of the motorcycle tire 1 when traveling straight.

[0037] The first block 5 may be, for example, the second middle portion 8B of the middle block 8. In this case, the second block 6 is the crown block 9. That is, the first block 5 is the middle block 8, and the second block 6 in this case is the crown block 9. Such a motorcycle tire 1 can simultaneously achieve grip performance, transient characteristics, and uneven wear resistance when the camber angle due to rolling is small.

[0038] That is, the first blocks 5 are, for example, at least one of the shoulder first portions 7A, shoulder second portions 7B, and middle second portions 8B. In this case, the second blocks 6 are at least one of the middle first portions 8A, middle second portions 8B, and crown blocks 9. Such a motorcycle tire 1 can simultaneously achieve grip performance at any camber angle during rolling, transient characteristics, and uneven wear resistance, depending on the required performance.

[0039] The profile surface Ps includes, for example, a first profile surface Ps1 constituted by the shoulder first portion 7A and the middle first portion 8A, and a second profile surface Ps2 constituted by the shoulder second portion 7B, the middle second portion 8B, and the crown block 9. Such a profile surface Ps is useful for improving the transient characteristics when the camber angle due to rolling of the motorcycle tire 1 is large, and when the camber angle due to rolling is small.

[0040] The first profile surface Ps1 of this embodiment is located radially outward of the second profile surface Ps2. Such a profile surface Ps can exert an edge effect due to the first profile surface Ps1 and an edge effect due to the second profile surface Ps2, which helps to improve the grip performance of the motorcycle tire 1.

[0041] It is desirable that the first blocks 5 and the second blocks 6 do not overlap with each other in the tire circumferential direction. In this embodiment, the shoulder blocks 7 and the middle blocks 8 do not overlap with each other in the tire circumferential direction. In this type of tread portion 2, the first blocks 5 and the second blocks 6 can independently exert edge effects, which helps to improve the grip performance of the motorcycle tire 1 during rolling.

[0042] As shown in FIG. 4, the motorcycle tire 1 of this embodiment has a pair of sidewall portions 11 extending radially inward from both sides of the tread portion 2, and a pair of bead portions 12 located radially inward of the pair of sidewall portions 11.

[0043] Each bead portion 12 of the present embodiment has a bead core 13 extending in the tire circumferential direction and a bead apex 14 extending radially outward from the bead core 13. Such a motorcycle tire 1 helps to suppress deformation of the bead portion 12 and improve uneven wear resistance.

[0044] The motorcycle tire 1 of this embodiment includes a carcass 15 that extends between a pair of bead portions 12 via a tread portion 2 and a pair of sidewall portions 11, and a reinforcing layer 16 that is disposed radially outward of the carcass 15 in at least the tread portion 2. Such a motorcycle tire 1 can firmly support the multiple blocks 4, which helps improve grip performance.

[0045] The carcass 15 includes at least one carcass ply 15A, two in this embodiment. Each carcass ply 15A in this embodiment has a main body portion 15a extending between a pair of bead portions 12, and a turned-up portion 15b that is continuous with the main body portion 15a and is turned up around the bead core 13 of the bead portion 12 from the inside to the outside in the tire axial direction. Such a carcass 15 increases the rigidity of the sidewall portions 11 and the bead portions 12, and is useful for improving the transient characteristics of the motorcycle tire 1 during rolling.

[0046] The reinforcing layer 16 includes at least one outer ply 16A, one outer ply 16A in this embodiment. The outer ply 16A extends, for example, to the pair of sidewall portions 11. Such a reinforcing layer 16 can increase the rigidity of the tread portion 2, suppress deformation during rolling, and help improve the transient characteristics of the motorcycle tire 1 during rolling.

[0047] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment and can be modified and practiced in various ways. [Example]

[0048] Motorcycle tires having the basic tread pattern shown in FIG. 1 and the basic structure shown in FIG. 4 were prototyped based on the specifications in Table 1. As a comparative example, a motorcycle tire was prototyped in which the profile surfaces of the conventional shoulder blocks protruded radially outward beyond the profile surfaces of the middle blocks. The prototype test tires were used to test grip performance during rolling, transient characteristics, and uneven wear resistance. The common specifications and test methods for each test tire are as follows:

[0049] <Common specifications> Tire size: 120 / 90-19 66M Air pressure: 80kPa Test vehicle: 450cc 4-stroke engine vehicle Test course: Dry off-road course

[0050] <Grip performance when rolling> Using a test vehicle fitted with the test tire on the rear wheel, the test riders evaluated the grip performance when rolling on a test course. The results were indexed with the comparative example being set at 100, with a higher value indicating greater grip and better grip performance during rolling.

[0051] <Transient characteristics during rolling> A test vehicle fitted with the test tire on the rear wheel was rolled on a test course, and the transient characteristics were evaluated by a test rider. The results were indexed, with the comparative example being set at 100, with a higher index indicating smoother changes during rolling and superior transient characteristics during rolling.

[0052] <Uneven wear resistance> A test rider mounted the test tire on the rear wheel of a test vehicle and drove it on the test course for two hours. After the drive, the wear on the shoulder blocks and middle blocks was measured, and the difference between the wear on the shoulder blocks and the middle blocks was evaluated as the amount of uneven wear. The results were indexed, with the comparative example being set at 100, and the higher the number, the smaller the amount of uneven wear and the better the uneven wear resistance.

[0053] The test results are shown in Table 1. [Table 1]

[0054] As a result of the test, it was confirmed that the motorcycle tires of the examples had grip performance, transient characteristics, and uneven wear resistance performance equal to or better than those of the comparative examples, and were also superior in overall performance, which is evaluated as the sum of these performances. Therefore, it was confirmed that the motorcycle tires of the examples had grip performance, transient characteristics, and uneven wear resistance performance during rolling all at once.

[0055] [Note] The present invention is as follows.

[0056] [Invention 1] A motorcycle tire for rough terrain driving having a tread portion, The tread portion includes a plurality of blocks protruding from a groove bottom surface, the plurality of blocks include a first block and a second block located axially inward of the first block, the first block has a first ground contact surface that comes into contact with a road surface during running, and a first side surface that extends from a first ground contact end on the inner side in the tire axial direction of the first ground contact surface to the inner side in the tire radial direction and reaches the groove bottom surface, the second block has a second ground contact surface that comes into contact with a road surface during running, and a second side surface that extends from a second ground contact end that is on the outer side in the tire axial direction of the second ground contact surface to the inner side in the tire radial direction and reaches the groove bottom surface, The first ground surface and the second ground surface form the same profile surface, the first side surface and the second side surface intersect at a virtual intersection point in a projection plane projected onto a common tire meridian cross section along the tire circumferential direction, a first distance along the first side surface from the virtual intersection to the first ground end is greater than a second distance along the second side surface from the virtual intersection to the second ground end; Tires for motorcycles.

[0057] [Invention 2] The motorcycle tire according to Invention 1, wherein, on the projection plane, the difference between the first distance and the second distance is 5 mm or less.

[0058] [Invention 3] 3. The motorcycle tire according to claim 1, wherein, in the projection plane, the angle formed between the first ground contact surface of the first ground contact end and the first side surface is 80 to 100°.

[0059] [Invention 4] The motorcycle tire according to any one of claims 1 to 3, wherein, in the projection plane, the first side surface includes at least one bend portion between the first ground contact end and the virtual intersection point, the angle of which relative to the tire radial direction changes.

[0060] [Invention 5] 5. The motorcycle tire according to any one of claims 1 to 4, wherein, on the projection plane, the shortest distance from the profile surface to the virtual intersection is 70% or more of the first block height from the groove bottom surface to the first contact patch.

[0061] [Invention 6] The plurality of blocks include shoulder blocks that form tread edges and middle blocks that are adjacent to the shoulder blocks on the inside in the tire axial direction, the first block is the shoulder block, 6. The motorcycle tire according to any one of claims 1 to 5, wherein the second block is the middle block.

[0062] [Invention 7] the plurality of blocks includes a crown block adjacent to the middle block on the inner side in the tire axial direction, the first block is the middle block, 7. A motorcycle tire according to claim 6, wherein the second block is the crown block.

[0063] [Invention 8] The motorcycle tire according to any one of Inventions 1 to 7, wherein the first blocks and the second blocks do not have any overlapping portions in the tire circumferential direction. [Explanation of symbols]

[0064] 1. Motorcycle tires 2 Tread section 3 Groove bottom surface 5 Block 1 5a 1st ground plane 5b 1st ground terminal 5c 1st side 6 Block 2 6a 2nd ground plane 6b 2nd ground terminal 6c 2nd side

Claims

1. A motorcycle tire for rough terrain driving having a tread portion, The tread portion includes a plurality of blocks protruding from a groove bottom surface, the plurality of blocks include a first block and a second block located axially inward of the first block, the first block has a first ground contact surface that comes into contact with a road surface during running, and a first side surface that extends from a first ground contact end that is on the inner side in the tire axial direction of the first ground contact surface to the inner side in the tire radial direction and reaches the groove bottom surface, the second block has a second ground contact surface that comes into contact with a road surface during running, and a second side surface that extends from a second ground contact end that is on the outer side in the tire axial direction of the second ground contact surface toward the inner side in the tire radial direction and reaches the groove bottom surface, the first ground plane and the second ground plane form the same profile surface; the first side surface and the second side surface intersect at a virtual intersection point in a projection plane projected onto a common tire meridian cross section along the tire circumferential direction, a first distance from the virtual intersection to the first ground end along the first side surface is greater than a second distance from the virtual intersection to the second ground end along the second side surface; Tires for motorcycles.

2. The motorcycle tire according to claim 1, wherein, on the projection plane, a difference between the first distance and the second distance is 5 mm or less.

3. 3. The motorcycle tire according to claim 1, wherein an angle formed between the first ground contact surface at the first ground contact end and the first side surface on the projection plane is 80 to 100 degrees.

4. The motorcycle tire according to claim 3 , wherein, in the projection plane, the first side surface includes at least one bent portion between the first ground contact end and the virtual intersection point, the angle of which with respect to the tire radial direction changes.

5. 3. The motorcycle tire according to claim 1, wherein, on the projection plane, the shortest distance from the profile surface to the virtual intersection is 70% or more of a first block height from the groove bottom surface to the first contact patch.

6. The plurality of blocks include shoulder blocks that form tread edges and middle blocks that are adjacent to the shoulder blocks on the inside in the tire axial direction, the first block is the shoulder block, The motorcycle tire according to claim 1 or 2, wherein the second block is the middle block.

7. the plurality of blocks includes a crown block adjacent to the middle block on the inner side in the tire axial direction, the first block is the middle block, The motorcycle tire according to claim 6, wherein the second block is the crown block.

8. The motorcycle tire according to claim 1 or 2, wherein the first blocks and the second blocks do not have portions that overlap with each other in the tire circumferential direction.

Images