JP2019073247A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire that enables both abrasion characteristic and traction performance.SOLUTION: One center main groove 11 and a pair of shoulder main grooves 12 are formed in a tread part 1. A center rib line 21 is sectioned between the center main groove 11 and each shoulder main groove 12. A shoulder rib line 22 is sectioned outside each shoulder main groove 12. Formed in each center rib line 21 are: a lug groove 31 one end of which opens in the corresponding shoulder main groove 12 and the other end of which terminates in the center rib line 21; and siping 41 both ends of which terminate in the center rib line 21. A first plane region A1 with no groove component is formed in a center main groove 11 side portion of each center rib line 21. Formed in each shoulder rib line 22 are: a lug groove 32 one end of which opens in the corresponding shoulder main groove 12 and the other end of which terminates in the shoulder rib line 22; and siping 42 both ends of which terminate in the shoulder rib line 22. A second plane region A2 with no groove component is formed in a ground end side portion of each shoulder rib line 22.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire suitable for a small truck, and more particularly to a pneumatic tire capable of achieving both wear characteristics and traction performance.

  Conventionally, as a pneumatic tire used for a small truck, a tread includes a center main groove extending in the tire circumferential direction and a pair of shoulder main grooves extending in the tire circumferential direction on both sides of the center main groove, A center rib row is defined between the center main groove and each shoulder main groove, and a shoulder rib row is defined outside each shoulder main groove, and one end of each of the center rib row and the shoulder rib row is open to the main groove On the other hand, a structure has been proposed in which a plurality of lug grooves are formed, the other end of which is terminated in the rib row (see, for example, Patent Document 1).

  In the pneumatic tire thus configured, it is possible to improve the traction performance by increasing the area of the lug grooves. However, when the area of the lug grooves is increased, uneven wear tends to occur in the tread portion, the tread portion is easily worn, and the wear characteristics of the tire generally deteriorate. In the case of pneumatic tires for small trucks, in particular, it is required to improve both the wear characteristics and the traction performance, but it is difficult to achieve both the wear characteristics and the traction performance that are in a contradictory relationship with conventional tread patterns. is there.

Patent No. 4407765

  An object of the present invention is to provide a pneumatic tire capable of achieving both wear characteristics and traction performance.

A pneumatic tire according to the present invention for achieving the above object comprises a tread portion extending in the circumferential direction of the tire to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and these sidewall portions A pneumatic tire including a pair of bead portions disposed inward in the tire radial direction of
In the tread portion, one center main groove extending in the tire circumferential direction and a pair of shoulder main grooves extending in the tire circumferential direction are formed on both sides of the center main groove, and between the center main groove and each shoulder main groove The center rib row is divided into two, and the shoulder rib row is divided outside each shoulder main groove,
In each center rib row, a plurality of lug grooves having one end opened in the shoulder main groove and the other end terminated in the center rib row, and a plurality of narrow grooves in which both ends are terminated in the center rib row A sipe is formed, and a first plain region in which no groove component is disposed when the tread portion is projected in the tire circumferential direction is formed in a portion on the center main groove side of each center rib row,
In each shoulder rib row, a plurality of lug grooves having one end opened in the shoulder main groove and the other end terminating in the shoulder rib row, and a plurality of narrow grooves in which both ends terminate in the shoulder rib row While the sipe is formed, a second plain region in which the groove component is not disposed when the tread portion is projected in the tire circumferential direction is formed in the portion on the ground contact end side of each shoulder rib row. It is a feature.

  In the present invention, each center rib row has a plurality of lug grooves having one end opened in the shoulder main groove and the other end terminated in the center rib row, and a plurality of narrow ends each terminated in the center rib row. A groove or sipe is formed, and each shoulder rib row has a plurality of lug grooves having one end opened in the shoulder main groove and the other end terminated in the shoulder rib row, and a plurality of both ends terminated in the shoulder rib row Since the narrow grooves or sipes are formed, good traction performance can be exhibited while maintaining the rigidity of the center rib row and the shoulder rib row. In addition, the first plain region in which the groove component is not disposed is formed in the portion on the center main groove side of each center rib row, and the groove component is not disposed in the portion on the ground end of each shoulder rib row Since the second plain area is formed, the first and second plain areas play a role of firmly and uniformly supporting the tread portion, and it is possible to effectively suppress uneven wear of the tread portion. This makes it possible to achieve both wear characteristics and traction performance. The narrow groove or sipe is a groove having a groove width of 2.0 mm or less.

  In the present invention, the ratio W1 / Wce of the width Wce of the center rib row to the width W1 of the first plain region is in the range of 0.16 ≦ W1 / Wce ≦ 0.40, and the width Wsh of the shoulder rib row and the first width Wsh It is preferable that the ratio W2 / Wsh to the width W2 of the 2 plane area is in the range of 0.16 ≦ W2 / Wsh ≦ 0.40. Further, the ratio W / TCW of the total width W of the first and second plain regions formed in the tread portion to the contact width TCW of the tread portion is in the range of 0.12 ≦ W / TCW ≦ 0.27. Is preferred. This makes it possible to achieve both wear characteristics and traction performance at a higher level.

  The inclination angle θ1 of the narrow groove or sipe formed in the center rib row with respect to the tire circumferential direction is 40 ° or less, and the inclination angle θ2 of the narrow groove or sipe formed in the shoulder rib array with respect to the tire width direction is 40 ° or less Is preferred. By arranging narrow grooves or sipes oriented in the tire circumferential direction in the center rib row where the contact length becomes long, traction in the tire width direction can be secured, and the tire in the shoulder rib row to which lateral force is applied during turning By arranging narrow grooves or sipes oriented in the width direction, traction in the tire circumferential direction can be ensured while securing the rigidity in the tire width direction of the shoulder rib row.

  Preferably, the center main groove has a zigzag shape which is periodically displaced in the tire width direction along the tire circumferential direction. Thereby, the traction in the tire circumferential direction can be enhanced.

  In particular, the end position of the lug groove formed in the center rib row and the apex position in the width direction outer side of the main groove having the zigzag shape are shifted in the tire circumferential direction, and from any vertex position of the main groove to the tire circumferential direction The ratio L1 / L2 of the circumferential distance L1 to the end position of the lug groove on one side and the circumferential distance L2 from the arbitrary vertex position of the main groove to the end position of the lug groove on the other side in the tire circumferential direction is It is preferable to be in the range of 0.8 ≦ L1 / L2 ≦ 1.2. In this case, since the rigidity of the center rib row in the circumferential direction of the tire is reduced, in improving the traction performance based on the center main groove having a zigzag shape, it is possible to maintain good wear characteristics of the tread portion. it can.

  In the present invention, the width Wce of the center rib row, the width Wsh of the shoulder rib row, the width W1 of the first plain region and the width W2 of the second plain region are measured in the tire axial direction measured in the tread region. Is the width of The contact area of the tread portion is specified based on the contact width in the tire axial direction measured when a tire is rimmed on a regular rim and filled with a regular internal pressure and placed vertically on a plane and a regular load is applied. Be done. The “regular rim” is a rim that defines the standard for each tire in the standard system including the standard on which the tire is based, for example, the standard rim for JATMA, “Design Rim” for the TRA, or ETRTO In the case of “Measuring Rim”. The “normal internal pressure” is the air pressure specified by each standard in the standard system including the standard to which the tire is based, and in the case of JATMA, the maximum air pressure, in the case of TRA, the table “TIRE ROAD LIMITS AT VARIOUS The maximum value described in "COLD INFlation PRESSURES" is "INFLATION PRESSURE" in the case of ETRTO, but is 180 kPa when the tire is for a passenger car. The “regular load” is a load defined by each standard in the standard system including the standard to which the tire is based, and in the case of JATMA, the maximum load capacity, in the case of TRA, the table “TIRE ROAD LIMITS AT VARIOUS In the case of ETRTO, the maximum value described in "COLD INFlation PRESSURES" is "LOAD CAPACITY", but when the tire is for a passenger car, the load corresponds to 88% of the load.

1 is a meridional cross-sectional view showing a pneumatic tire according to an embodiment of the present invention. 1 is a development view showing a tread pattern of a pneumatic tire according to an embodiment of the present invention. It is a meridional sectional view showing a pneumatic tire according to another embodiment of the present invention. It is an expanded view which shows the tread pattern of the pneumatic tire which consists of other embodiment of this invention. It is a top view which shows the principal part of the tread pattern of FIG.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the attached drawings. 1 and 2 show a pneumatic tire according to an embodiment of the present invention. In FIG. 2, Tc is a tire circumferential direction, and Tw is a tire width direction.

  As shown in FIG. 1, the pneumatic tire according to the present embodiment includes a tread portion 1 extending in the circumferential direction of the tire to form an annular shape, and a pair of sidewall portions 2 and 2 disposed on both sides of the tread portion 1. And a pair of bead portions 3 and 3 disposed on the inner side in the tire radial direction of the side wall portions 2.

  A carcass layer 4 is mounted between the pair of bead portions 3 and 3. The carcass layer 4 includes a plurality of carcass cords extending in the tire radial direction, and is folded from the inside to the outside around the bead cores 5 disposed in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross section is disposed on the outer periphery of the bead core 5.

  On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. The belt layers 7 include a plurality of belt cords inclined with respect to the tire circumferential direction, and the belt cords are arranged so as to cross each other between layers. As a belt cord which constitutes belt layer 7, a steel cord is used preferably.

  As shown in FIG. 2, the tread portion 1 has one center main groove 11 extending in the tire circumferential direction on the tire equator, and a pair of shoulder main grooves 12 extending in the tire circumferential direction on both sides of the center main groove 11. And are formed. A center rib row 21 is defined between the center main groove 11 and each shoulder main groove 12, and a shoulder rib row 22 is defined outside the shoulder main grooves 12.

  Each center rib row 21 has a plurality of lug grooves 31 having one end opened in the shoulder main groove 12 and the other end terminated in the center rib row 21, and a plurality of both ends terminated in the center rib row 21. A sipe (or narrow groove) 41 is formed. The lug grooves 31 are inclined with respect to the tire width direction, and are arranged at intervals along the tire circumferential direction. The sipes 41 are disposed between the lug grooves 31. Then, a first plain area A1 (hatched portion) in which no groove component is disposed when the tread portion 1 is projected in the tire circumferential direction is formed in a portion on the center main groove 11 side of each center rib row 21 ing. That is, the first plain area A1 is an area which is continuous in a band shape along the tire circumferential direction without including the groove component.

  Each shoulder rib row 22 has a plurality of lug grooves 32 having one end opened in the shoulder main groove 12 and the other end terminated in the shoulder rib row 22 in the ground contact area having a ground contact width TCW, and both ends shoulder A plurality of sipes (or narrow grooves) 42 terminating in the rib row 22 are formed. The lug grooves 32 are inclined with respect to the tire width direction and arranged at intervals along the tire circumferential direction. The sipes 42 are disposed between the lug grooves 32. Further, in each shoulder rib row 22, a plurality of lug grooves 33 inclined with respect to the tire width direction and a plurality of sipes (or narrow grooves) whose both ends are terminated in the shoulder rib row 22 outside the contact area. And 43) are alternately arranged along the tire circumferential direction. Then, in the ground contact region, a second plain region A2 (hatched portion) in which no groove component is arranged when the tread portion 1 is projected in the tire circumferential direction at a portion on the ground contact end side of each shoulder rib row 22 Is formed. That is, the second plain area A2 is an area that is continuous in a band shape along the tire circumferential direction without including the groove component.

  In the pneumatic tire described above, each center rib 21 row has a plurality of lug grooves 31 having one end opened in the shoulder main groove 12 and the other end terminated in the center rib row 21, and both ends in the center rib row 21. A plurality of sipes 41 are formed at each end, and each shoulder rib row 22 has a plurality of lug grooves 32 having one end opened in the shoulder main groove 12 and the other end terminated in the shoulder rib row 22, and both ends Since the plurality of sipes 42 terminating in the shoulder rib 22 row are formed, it is possible to exhibit good traction performance while maintaining the rigidity of the center rib row 21 and the shoulder rib row 22. In other words, the lug grooves 31 and 32 closed on one side and the sipes 41 and 42 whose both ends are closed and the groove width is narrow do not significantly reduce the rigidity of the center rib row 21 and the shoulder rib row 22 in traction performance. It contributes to improvement.

  In addition, a first plain area A1 in which no groove component is disposed is formed in a portion on the center main groove 11 side of each center rib row 21, and a groove component is formed in a portion on the ground end of each shoulder rib row 22. Since the second plain area A2 which is not disposed is formed, the first and second plain areas A1 and A2 play a role of firmly and uniformly supporting the tread portion 1 and uneven wear of the tread portion 1 Can be effectively suppressed. This makes it possible to achieve both wear characteristics and traction performance.

  In the pneumatic tire, the ratio W1 / Wce of the width Wce of the center rib row 21 to the width W1 of the first plain area A1 is in the range of 0.16 ≦ W1 / Wce ≦ 0.40, and the shoulder rib row 22 The ratio W2 / Wsh between the width Wsh of the second plane area A2 and the width W2 of the second plane area A2 is preferably in the range of 0.16 ≦ W2 / Wsh ≦ 0.40. This makes it possible to achieve both wear characteristics and traction performance at a higher level.

  Here, if the ratio W1 / Wce or the ratio W2 / Wsh is less than 0.16, the rigidity of the center rib row 21 or the shoulder rib row 22 decreases, so the effect of improving the wear characteristics decreases, conversely 0.40 If it exceeds, the component in the width direction of the lug groove 31 or the lug groove 32 runs short, and the improvement effect of the traction performance decreases. In particular, when the center rib row 21 has a straight shape, the ratio W1 / Wce is preferably in the range of 0.22 ≦ W1 / Wce ≦ 0.36, and when the center rib row 21 has a zigzag shape, the ratio W1 It is desirable that / Wce be in the range of 0.20 ≦ W1 / Wce ≦ 0.24. The width Wce of the center rib row 21 and the width Wsh of the shoulder rib row 22 are preferably equal, and the width W1 of the first plane area A1 and the width W2 of the second plane area A2 are equal. Is desirable.

  In the pneumatic tire described above, the ratio W / of the total width W of the first and second plain regions A1 and A2 formed in the tread portion 1 (W = W1 × 2 + W2 × 2) and the contact width TCW of the tread portion 1 It is preferable that TCW be in the range of 0.12 ≦ W / TCW ≦ 0.27. This makes it possible to achieve both wear characteristics and traction performance at a higher level. Here, if the ratio W / TCW is less than 0.12, the rigidity of the center rib row 21 or the shoulder rib row 22 is reduced, so the effect of improving the wear characteristics is reduced. Alternatively, since the width direction component of the lug groove 32 is insufficient, the improvement effect of the traction performance is reduced.

  3 to 5 show a pneumatic tire according to another embodiment of the present invention. The present embodiment is different from the above-described embodiment only in the shape of the center main groove, so in FIGS. 3 to 5 the same parts as those in FIGS. Description is omitted.

  In FIG. 3 and FIG. 4, the tread portion 1 includes one center main groove 11 extending in the tire circumferential direction on the tire equator, and a pair of shoulder main grooves 12 extending in the tire circumferential direction on both sides of the center main groove 11. And are formed. While the shoulder main groove 12 has a straight shape, the center main groove 11 has a zigzag shape which is periodically displaced in the tire width direction along the tire circumferential direction. As described above, when the center main groove 11 has a zigzag shape, it is possible to further improve the traction performance in the tire circumferential direction.

  In particular, it is desirable that the end position Pa of the lug groove 31 formed in the center rib row 21 and the apex position Pb outside the width direction of the main groove 11 having a zigzag shape be mutually offset in the tire circumferential direction. More specifically, as shown in FIG. 5, the circumferential distance L1 from the arbitrary vertex position Pb of the main groove 11 to the end position Pa of the lug groove 31 on one side in the tire circumferential direction and the arbitrary distance of the main groove 11 The ratio L1 / L2 to the circumferential distance L2 from the top position Pb of the tire to the end position Pa of the lug groove 31 on the other side in the tire circumferential direction is preferably in the range of 0.8 ≦ L1 / L2 ≦ 1.2. . By arranging the apex position Pb of the main groove 11 in the middle of the end position Pa of the pair of lug grooves 31 adjacent to each other in the tire circumferential direction as described above, the rigidity of the center rib row 21 in the tire circumferential direction is uneven. Since it becomes smaller, when improving the traction performance based on the center main groove 11 having a zigzag shape, the wear characteristics of the tread portion 1 can be maintained well. Here, when the end position Pa of the lug groove 31 and the apex position Pb of the main groove 11 come close to each other, the center rib row 21 is locally narrowed, so that the center rib row 21 is formed. Non-uniformities in the tire circumferential direction of stiffness increase, and the effect of improving the wear characteristics decreases.

  In addition, the inclination angle θ1 of the sipe (or narrow groove) 41 formed in the center rib row 21 with respect to the tire circumferential direction is 40 ° or less, and the tire width of the sipe (or narrow groove) 42 formed in the shoulder rib row 22 The inclination angle θ2 with respect to the direction is preferably 40 ° or less. By arranging the sipe (or narrow groove) 41 oriented in the tire circumferential direction in the center rib row 21 where the contact length is long, traction in the tire width direction can be secured, and a shoulder in which a lateral force is applied when turning By arranging the sipe (or narrow groove) 42 oriented in the tire width direction in the rib row 21, traction in the tire circumferential direction can be ensured while securing the rigidity in the tire width direction of the shoulder rib row 21. Here, when the inclination angle θ1 exceeds 40 °, the effect of increasing the traction in the tire width direction decreases, and when the inclination angle θ2 exceeds 40 °, the effect of increasing the traction in the tire circumferential direction decreases.

  The pneumatic tire described above is particularly suitable for small trucks because of its excellent wear characteristics and traction performance. However, the pneumatic tire according to the present invention can also be used for passenger cars, trucks and buses.

  In a pneumatic tire having a tire size of 145 / 80R12 80 / 78N and having a tread portion, a pair of sidewall portions and a pair of bead portions, one tread main groove and a pair of shoulder main grooves are formed in the tread portion A center rib row is defined between the center main groove and each shoulder main groove, a shoulder rib row is defined outside each shoulder main groove, and one end of each center rib row is open to the shoulder main groove A plurality of lug grooves (center lug grooves) whose other ends end in the center rib row and a plurality of sipes whose both ends end in the center rib row are formed, and the center main groove side of each center rib row is formed A first plain region in which no groove component is disposed is formed in the portion, and in each shoulder rib row, one end is open to the shoulder main groove and the other end is in the shoulder rib row A plurality of terminating lug grooves (shoulder lug grooves) and a plurality of sipes whose both ends are terminated in the shoulder rib row are formed, and no groove component is disposed in the portion on the ground end side of each shoulder rib row The tires of Examples 1 to 7 were produced in which the second plain area was formed and the setting conditions shown in Tables 1 and 2 were made.

  For comparison, a conventional example having the same structure as in Example 1 except that a main groove was added on the ground contact end side than the shoulder main groove and the lug grooves of the shoulder rib row were opened in the main groove on the ground end side. I prepared a tire. In addition, tires of Comparative Examples 1 to 4 having the same structure as Example 1 were prepared except that the arrangement of the plain area and / or the sipe was different.

  With respect to the center lug groove and the shoulder lug groove, the “one-sided opening” means a structure in which one end is open to the main groove and the other end is terminated in the rib. The “width direction” of the sipe means that the sipe is oriented in the tire width direction, and the “circumferential direction” means that the sipe is oriented in the tire circumferential direction.

  With respect to these test tires, traction performance and wear characteristics were evaluated by the following test methods, and the results are shown in Table 1 and Table 2.

Traction performance:
Each test tire is mounted on a wheel of rim size 12 × 4.00 B and mounted on a light cargo car, and the air pressure (front wheel / rear wheel) is 280 kPa / 350 kPa, and the soil is evenly spread on the unpaved road to adjust the road surface ( The average acceleration at an acceleration of 0 to 20 km / h and the average lateral acceleration at a turn of a radius of 10 m were determined on a saddle road). The evaluation results are indicated by an index where the conventional example is 100. The larger the index value, the better the traction performance.

Wear characteristics:
Each test tire is mounted on a wheel of rim size 12 × 4.00 B and mounted on a light cargo vehicle, and the air pressure (front wheel / rear wheel) is 280 kPa / 350 kPa. After traveling 20,000 km at a ratio of about half in a mountainous area, the wear amounts of the center main groove and the shoulder main groove were respectively measured. As the uneven wear resistance, the ratio of the wear rate of the center main groove to the wear rate of the shoulder main groove was determined, and the index where the ratio is 1.0 is shown as an index 100. The closer the index value is to 100, the less the uneven wear, and if it is 95 or more, there is no problem in practical use. The wear rate of each main groove is the ratio of the amount of wear to the effective groove depth up to the wear indicator. Further, as the wear life, the travel distance at the time of total wear was estimated from the wear rate of the shoulder main groove and the wear rate of the center main groove, and the index was shown with the conventional example as 100. The larger the index value, the longer the wear life.

  As can be seen from Tables 1 and 2, the tires of Examples 1 to 7 were able to improve the wear characteristics and the traction performance in a well-balanced manner in comparison with the conventional example. On the other hand, in the tires of Comparative Examples 1, 3 and 4, the improvement effect of the wear characteristics was insufficient because there was no plain region in at least one of the center rib row and the shoulder rib row. Further, in the tire of Comparative Example 2, since the sipes do not exist in the center rib row and the shoulder rib row and the plain area is excessive, the improvement effect of the traction performance is insufficient.

DESCRIPTION OF SYMBOLS 1 tread part 2 side wall part 3 bead part 11 center main groove 12 shoulder main groove 21 center rib row 22 shoulder rib row 31, 32, 33 lug groove 41, 42, 43 sipes

Claims (6)

A tread portion extending in the circumferential direction of the tire and forming an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the tire radial direction inner side of the sidewall portions In the equipped pneumatic tire,
In the tread portion, one center main groove extending in the tire circumferential direction and a pair of shoulder main grooves extending in the tire circumferential direction are formed on both sides of the center main groove, and between the center main groove and each shoulder main groove The center rib row is divided into two, and the shoulder rib row is divided outside each shoulder main groove,
In each center rib row, a plurality of lug grooves having one end opened in the shoulder main groove and the other end terminated in the center rib row, and a plurality of narrow grooves in which both ends are terminated in the center rib row A sipe is formed, and a first plain region in which no groove component is disposed when the tread portion is projected in the tire circumferential direction is formed in a portion on the center main groove side of each center rib row,
In each shoulder rib row, a plurality of lug grooves having one end opened in the shoulder main groove and the other end terminating in the shoulder rib row, and a plurality of narrow grooves in which both ends terminate in the shoulder rib row While the sipe is formed, a second plain region in which the groove component is not disposed when the tread portion is projected in the tire circumferential direction is formed in the portion on the ground contact end side of each shoulder rib row. Characteristic pneumatic tire.   The ratio W1 / Wce of the width Wce of the center rib row to the width W1 of the first plain region is in the range of 0.16 ≦ W1 / Wce ≦ 0.40, and the width Wsh of the shoulder rib row and the first width Wsh The pneumatic tire according to claim 1, characterized in that the ratio W2 / Wsh to the width W2 of the two plain areas is in the range of 0.16 ≦ W2 / Wsh ≦ 0.40.   The ratio W / TCW of the total width W of the first and second plain regions formed in the tread portion to the contact width TCW of the tread portion is in the range of 0.12 ≦ W / TCW ≦ 0.27. The pneumatic tire according to claim 2, characterized in that.   The inclination angle θ1 of the narrow groove or sipe formed in the center rib row with respect to the tire circumferential direction is 40 ° or less, and the inclination angle θ2 of the narrow groove or sipe formed in the shoulder rib array with respect to the tire width direction is 40 ° It is the following, The pneumatic tire in any one of the Claims 1-3 characterized by the above-mentioned.   The pneumatic tire according to any one of claims 1 to 4, wherein the center main groove has a zigzag shape periodically displaced in the tire width direction along the tire circumferential direction.   The end position of the lug groove formed in the center rib row and the apex position in the width direction outer side of the main groove having the zigzag shape are shifted in the tire circumferential direction, and from the arbitrary apex position of the main groove to the tire circumferential direction A circumferential distance L1 to the end position of the lug groove on one side of the tire and a circumferential distance L2 from the arbitrary vertex position of the main groove to the end position of the lug groove on the other side of the tire circumferential direction The pneumatic tire according to claim 5, wherein the ratio L1 / L2 is in the range of 0.80.8L1 / L2 ≦ 1.2.

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