JP7056392B2 - tire - Google Patents

Description

The present invention relates to a tire, and more particularly to a tire suitable for high-speed traveling.

The following Patent Document 1 proposes tires used for both public road traveling and circuit traveling. In order to ensure wet performance on public roads, the tire has a first main groove and a second main groove continuously extending in the tire circumferential direction in the inner tread portion between the tire equator and the inner tread ground contact end. Have. Further, the tire is not provided with a groove continuously extending in the tire circumferential direction in the outer tread portion between the tire equator and the outer tread ground contact end.

Japanese Unexamined Patent Publication No. 2017-03604

However, the first main groove and the second lateral groove have a problem that water between the outer tread portion and the road surface cannot be sufficiently discharged during wet running. On the other hand, when the outer tread portion is provided with the same main grooves as the first main groove and the second main groove, there is a problem that the pattern rigidity of the outer tread portion is lowered and the cornering performance on the dry road surface is deteriorated. ..

The present invention has been devised in view of the above problems, and an object of the present invention is to provide a tire capable of achieving both cornering performance and wet performance on a dry road surface.

The present invention is a tire having a tread portion whose mounting direction on a vehicle is specified, and the tread portion has an inner tread grounding end that is inside the vehicle when mounted on the vehicle and an outer tread that is outside the vehicle when mounted on the vehicle. The ground contact end, the inner main groove continuously extending in the tire circumferential direction between the inner tread ground contact end and the tire equatorial line, and the tire circumferential direction continuously extending between the outer tread ground contact end and the tire equatorial line. An outer tread having a groove width smaller than that of the inner main groove, a central main groove continuously extending in the tire circumferential direction between the inner main groove and the outer fine groove, and the central main groove and the outer fine groove. It is desirable that the outer crown land portion is provided with an outer crown land portion separated from the groove, and the outer crown land portion is provided with a plurality of outer crown lateral grooves having both ends interrupted within the outer crown land portion.

In the tire of the present invention, the tread portion has an outer shoulder land portion divided between the outer tread ground contact end and the outer groove, and the outer shoulder land portion communicates with the outer groove. It is desirable that the horizontal groove is not provided.

In the tire of the present invention, it is desirable that the outer shoulder land portion is a plain rib having no groove.

In the tire of the present invention, it is desirable that the groove width of the central main groove is larger than the groove width of the outer fine groove and smaller than the groove width of the inner main groove.

In the tire of the present invention, the tread portion has an inner crown land portion divided between the inner main groove and the central main groove, and the inner crown land portion extends from the inner main groove and extends from the inner main groove. It is desirable that a plurality of inner crown lateral grooves that are interrupted in the inner crown land portion are provided.

In the tire of the present invention, it is desirable that the inner crown lateral groove does not intersect the region where the outer crown lateral groove is projected along the tire axial direction.

In the tire of the present invention, the tread portion has an inner shoulder land portion divided between the inner tread ground contact end and the inner main groove, and the inner shoulder land portion is from the inner tread ground contact end. It is desirable to have a plurality of inner shoulder treads that extend and break within the inner shoulder tread.

In the tire of the present invention, it is desirable that the inner shoulder lateral groove does not intersect the region where the outer crown lateral groove is projected along the tire axial direction.

The tread portion of the tire of the present invention has an inner main groove that extends continuously in the tire circumferential direction between the inner tread ground contact end and the tire equatorial line, and a continuous tire circumferential direction between the outer tread contact end and the tire equatorial line. The outer tread that extends and has a groove width smaller than the inner tread, the central main groove that extends continuously in the tire circumferential direction between the inner main groove and the outer tread, and the central main groove and the outer tread. It has an outer crown tread separated from the groove. Further, the outer crown land portion is provided with a plurality of outer crown lateral grooves having both ends interrupted within the outer crown land portion.

The inner main groove and the central main groove of the present invention are useful for ensuring wet performance, for example, when traveling straight or when turning gently. Further, the outer narrow groove having a groove width smaller than that of the inner main groove, and the plurality of outer crown lateral grooves having both ends interrupted in the outer crown land portion are formed in the region between the central main groove of the tread portion and the outer tread ground contact end. It can exhibit drainage while maintaining rigidity. Therefore, the tire of the present invention can achieve both cornering performance and wet performance on a dry road surface.

It is a development view of the tread part of the tire of one Embodiment of this invention. FIG. 3 is a cross-sectional view taken along the line AA of FIG. It is an enlarged view of the outer crown land part and the outer shoulder land part of FIG. 1. It is an enlarged view of the inner crown land part and the inner shoulder land part of FIG. 1. FIG. 4 is a cross-sectional view taken along the line BB of FIG. It is a development view of the tread part of the tire of the comparative example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a developed view of the tread portion 2 of the tire 1 of the present embodiment. FIG. 2 shows a sectional view taken along line AA of the tread portion 2 of FIG. As shown in FIGS. 1 and 2, the tire 1 of the present embodiment is used, for example, as a pneumatic tire for a passenger car, and particularly as a high-performance tire premised on use in both public road driving and circuit driving. It is preferably used.

The tire 1 has a tread portion 2 whose mounting direction on the vehicle is designated. The direction of mounting on the vehicle is indicated by characters or marks on, for example, a sidewall portion (not shown). In FIGS. 1 and 2, when the tire 1 is mounted on the vehicle, the left side corresponds to the inside of the vehicle and the right side corresponds to the outside of the vehicle.

By designating the mounting direction on the vehicle, the tread portion 2 has an outer tread ground contact end To that is outside the vehicle when mounted on the vehicle and an inner tread ground contact end Ti that is inside the vehicle when mounted on the vehicle. ..

The outer tread ground contact end To and the inner tread ground contact end Ti are cambered by applying a normal load to the tire 1 in a normal state in which the rim is assembled to a normal rim (not shown), the normal internal pressure is applied, and there is no load. This is the outermost ground contact position in the tire axial direction when the tire is grounded on a flat surface at an angle of 0 °.

A "regular rim" is a rim defined for each tire in the standard system including the standard on which the tire is based. For example, "standard rim" for JATTA and "Design Rim" for TRA. If it is ETRTO, it is "Measuring Rim".

"Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which the tire is based. For JATTA, "maximum air pressure", for TRA, the table "TIRE LOAD LIMITS AT" The maximum value described in "VARIOUS COLD INFLATION PRESSURES", or "INFLATION PRESSURE" for ETRTO.

"Regular load" is the load defined for each tire in the standard system including the standard on which the tire is based. "Maximum load capacity" for JATTA and "TIRE LOAD LIMITS" for TRA. The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES", or "LOAD CAPACITY" for ETRTO.

The tread portion 2 includes an outer tread portion 4 between the tire equator C and the outer tread ground contact end To, and an inner tread portion 5 between the tire equator C and the inner tread ground contact end Ti. Further, the tread portion 2 has an inner main groove 6, an outer fine groove 7, and a central main groove 8.

The inner main groove 6 extends continuously in the tire circumferential direction between the inner tread ground contact end Ti and the tire equator C. The outer groove 7 extends continuously in the tire circumferential direction between the outer tread ground contact end To and the tire equator C. Further, the outer fine groove 7 has a groove width smaller than that of the inner main groove 6. The central main groove 8 extends continuously in the tire circumferential direction between the inner main groove 6 and the outer fine groove 7.

In the present embodiment, it is desirable that the distance L1 in the tire axial direction from the tire equator C to the groove center line of the inner main groove 6 is, for example, 0.50 to 0.65 times the tread half width TWh. The half-width tread TWh corresponds to the distance in the tire axial direction from the tire equator C to the outer tread ground contact end To or from the tire equator C to the inner tread ground contact end Ti in the normal state.

It is desirable that the distance L2 in the tire axial direction from the tire equator C to the groove center line of the outer narrow groove 7 is, for example, 0.65 to 0.75 times the tread half width TWh. In a more desirable embodiment, the outer groove 7 is arranged on the outer tread ground contact end To side of the center position of the outer tread portion 4 in the tire axial direction.

It is desirable that the distance L3 in the tire axial direction from the tire equator C to the groove center line of the central main groove 8 is, for example, 0.15 times or less of the tread half width TWh. In the present embodiment, the central main groove 8 is on the tire equator C, and the groove center line of the central main groove 8 is arranged on the inner tread ground contact end Ti side of the tire equator C.

The groove width W1 of the inner main groove 6 and the groove width W3 of the central main groove 8 have a groove width of at least 5.0 mm or more. In addition, in this specification, a "main groove" means a groove which extends continuously in the tire circumferential direction with a groove width of 5.0 mm or more. Further, the groove width corresponds to the distance between the two groove edges in the direction orthogonal to the length direction of the groove. In a preferred embodiment, the groove width W1 of the inner main groove 6 and the groove width W3 of the central main groove 8 are, for example, 7.0% to 20.0% of the tread half width TWh, and more preferably 15.0% to 20%. It is 0.0%.

In general, the tire 1 is often mounted on a vehicle with a negative camber. Therefore, the tire 1 tends to exert a relatively large contact pressure on the inner tread portion 5 when traveling straight or turning gently. Therefore, the inner main groove 6 and the central main groove 8 of the present invention are useful for ensuring wet performance, for example, when traveling straight or when turning gently.

In a more preferred embodiment, the groove width W3 of the central main groove 8 is larger than the groove width W2 of the outer fine groove 7 and smaller than the groove width W1 of the inner main groove 6. Such a central main groove 8 can improve wet performance while maintaining rigidity near the tire equator C.

The groove width W2 of the outer fine groove 7 has, for example, a groove width of less than 5.0 mm. The groove width W2 of the outer fine groove 7 is preferably, for example, 2.5% to 5.5% of the tread half width TWh.

As shown in FIG. 2, it is desirable that the depth d1 of the inner main groove 6 and the depth d3 of the central main groove 8 are at least 4.0 mm or more. More specifically, it is desirable that the depth d1 of the inner main groove 6 and the depth d3 of the central main groove 8 are 5.0 to 6.5 mm. As a result, the cornering performance and the wet performance on the dry road surface are improved in a well-balanced manner.

It is desirable that the inner main groove 6 and the central main groove 8 include, for example, a chamfered portion 10 having a recessed corner portion between the groove edge 9e and the groove wall 9w. The angle θ1 of the chamfered portion 10 with respect to the tread normal passing through the groove edge 9e is, for example, 35 to 70 °, more preferably 60 to 70 °. Such a chamfered portion 10 is useful for suppressing uneven wear of the groove edge while improving the drainage property of the main groove.

The depth d2 of the outer groove 7 is preferably at least 2.0 mm or more. The depth d2 of the outer groove 7 of the present embodiment is, for example, 4.5 to 6.0 mm. In a more preferred embodiment, the depth d2 of the outer groove 7 is smaller than the depth d1 of the inner main groove 6 and the depth d3 of the central main groove 8. Such an outer fine groove 7 helps to improve the wet performance while maintaining the rigidity of the outer tread portion 4.

As shown in FIG. 1, the tread portion 2 has the outer crown land portion 11, the outer shoulder land portion 12, and the inner crown due to the arrangement of the inner main groove 6, the central main groove 8, and the outer fine groove 7 described above. It has a land portion 13 and an inner shoulder land portion 14.

FIG. 3 shows an enlarged view of the outer crown land portion 11 and the outer shoulder land portion 12. As shown in FIG. 3, the outer crown land portion 11 is divided between the central main groove 8 and the outer narrow groove 7.

It is desirable that the width W4 of the outer crown land portion 11 in the tire axial direction is, for example, 0.50 to 0.70 times the tread half width TWh.

The outer crown land portion 11 is provided with a plurality of outer crown lateral grooves 15 having both ends interrupted within the outer crown land portion 11. The outer narrow groove 7 having a groove width smaller than that of the inner main groove 6 and the plurality of outer crown lateral grooves 15 having both ends interrupted in the outer crown land portion 11 are the central main groove 8 of the tread portion 2 and the outer tread ground contact end To. It is possible to exhibit drainage while maintaining the rigidity of the area between the tread and the tread. Therefore, the tire 1 of the present invention can achieve both cornering performance and wet performance on a dry road surface.

It is desirable that the outer crown lateral groove 15 is arranged at the center of the outer crown land portion 11 in the tire axial direction. Specifically, it is desirable that the outer crown lateral groove 15 crosses the center position of the outer crown land portion 11 in the tire axial direction. Such an outer crown lateral groove 15 can effectively enhance cornering performance and wet performance on a dry road surface, and can suppress uneven wear of the outer crown lateral groove 15.

The distance L4 in the tire axial direction from the end of the outer crown lateral groove 15 on the central main groove 8 side to the groove edge of the central main groove 8 is 0.20 to 0.35 times the width W4 of the outer crown land portion 11. Is desirable. Similarly, the distance L5 in the tire axial direction from the end of the outer crown lateral groove 15 on the outer tread ground contact end To side to the groove edge of the outer fine groove 7 is 0.20 to 0.35 of the width W4 of the outer crown land portion 11. It is desirable to double.

In a more desirable embodiment, it is desirable that the distance L4 and the distance L5 are smaller than the length L6 of the outer crown lateral groove 15 in the tire axial direction, respectively. The length L6 of the outer crown lateral groove 15 is, for example, 0.40 to 0.50 times the width W4 of the outer crown land portion 11. As a result, the length of the outer crown lateral groove 15 is secured, and excellent wet performance is exhibited.

It is desirable that the outer crown lateral groove 15 is arranged at an angle of 45 ° or less with respect to the tire axial direction, for example. The angle of the outer crown lateral groove 15 with respect to the tire axial direction is preferably 0 to 20 °, for example. Such an outer crown lateral groove 15 can maintain the lateral rigidity of the outer crown land portion 11 and can suppress deterioration of cornering performance on a dry road surface.

It is desirable that the groove width W5 of the outer crown lateral groove 15 is smaller than, for example, the groove width W1 of the inner main groove 6 and the groove width W3 of the central main groove 8. Further, it is desirable that the groove width W5 of the outer crown lateral groove 15 is larger than, for example, the groove width W2 of the outer fine groove 7. Specifically, it is desirable that the groove width W5 of the outer crown lateral groove 15 is, for example, 5.0 to 15.0 mm. Such an outer crown lateral groove 15 can enhance the cornering performance and the wet performance on a dry road surface in a well-balanced manner.

It is desirable that the depth of the outer crown lateral groove 15 is smaller than, for example, the depth d1 of the inner main groove 6 (shown in FIG. 2). Specifically, it is desirable that the depth of the outer crown lateral groove 15 is 0.85 to 0.95 times the depth d1 of the inner main groove 6.

It is desirable that the pitch P1 in the tire circumferential direction of the two outer crown lateral grooves 15 adjacent to each other in the tire circumferential direction is larger than, for example, the width W4 of the outer crown land portion 11. Specifically, the pitch P1 of the outer crown lateral groove 15 is 1.05 to 1.15 times the width W4 of the outer crown land portion 11. Such an arrangement of the outer crown lateral groove 15 helps to maintain the rigidity of the outer crown land portion 11. The pitch P1 is defined by the distance in the tire circumferential direction between the groove center lines of the two outer crown lateral grooves 15.

The outer shoulder land portion 12 is divided between the outer groove 7 and the outer tread ground contact end To. It is desirable that the width W6 of the outer shoulder land portion 12 in the tire axial direction is smaller than, for example, the width W4 of the outer crown land portion 11 in the tire axial direction. Specifically, it is desirable that the width W6 of the outer shoulder land portion 12 in the tire axial direction is 0.20 to 0.35 times the tread half width TWh.

It is desirable that the outer shoulder land portion 12 is not provided with a lateral groove communicating with the outer fine groove 7. In another aspect of the present invention, the outer shoulder land portion 12 may be provided with, for example, a lateral groove that does not communicate with the outer fine groove 7. The lateral groove is a notch having a width of 1.5 mm or more and extending in the tire axial direction. Therefore, in another aspect of the present invention, the outer shoulder land portion 12 may be provided with, for example, a so-called sipe having a width of less than 1.5 mm.

In a more preferred embodiment, the outer shoulder land portion 12 of the present embodiment is a plain rib without any grooves or sipes. Such an outer shoulder land portion 12 can exhibit high lateral rigidity together with the outer crown land portion 11 when, for example, a sharp turn is made on a dry road surface.

FIG. 4 shows an enlarged view of the inner crown land portion 13 and the inner shoulder land portion 14. As shown in FIG. 4, the inner crown land portion 13 is divided between the inner main groove 6 and the central main groove 8. It is desirable that the width W7 of the inner crown land portion 13 in the tire axial direction is smaller than, for example, the width W4 of the outer crown land portion 11 in the tire axial direction (shown in FIG. 3). Specifically, it is desirable that the width W7 of the inner crown land portion 13 is, for example, 0.35 to 0.50 times the tread half width TWh.

The inner crown land portion 13 is provided with, for example, a plurality of inner crown lateral grooves 20. The inner crown lateral groove 20 extends from the inner main groove 6 and is interrupted in the inner crown land portion 13. Such an inner crown lateral groove 20 can provide drainage while maintaining the rigidity of the inner tread ground contact end Ti side of the inner crown land portion 13.

It is desirable that the length L7 of the inner crown lateral groove 20 in the tire axial direction is, for example, 0.40 to 0.60 times the width W7 of the inner crown land portion 13 in the tire axial direction.

It is desirable that the inner crown lateral groove 20 is arranged at an angle of 45 ° or less with respect to the tire axial direction, for example. The angle of the inner crown lateral groove 20 with respect to the tire axial direction is preferably 0 to 20 °, for example. Such an inner crown lateral groove 20 is useful for maintaining the lateral rigidity of the inner crown land portion 13.

It is desirable that the groove width W8 of the inner crown lateral groove 20 is smaller than, for example, the groove width W1 of the inner main groove 6 and the groove width W3 of the central main groove 8 (shown in FIG. 1). Further, it is desirable that the groove width W8 of the inner crown lateral groove 20 is larger than, for example, the groove width W5 (shown in FIG. 3) of the outer crown lateral groove 15. Specifically, it is desirable that the groove width W8 of the inner crown lateral groove 20 is, for example, 5.0 to 15.0 mm.

It is desirable that the depth of the inner crown lateral groove 20 is larger than the depth of the outer crown lateral groove 15, for example. The inner crown lateral groove 20 of the present embodiment has the same depth as the inner main groove 6. Such an inner crown lateral groove 20 is useful for suppressing uneven wear of the inner crown land portion 13 while exhibiting excellent wet performance.

The pitch P2 in the tire circumferential direction of the two inner crown lateral grooves 20 adjacent to each other in the tire circumferential direction is, for example, 0.90 to 1.10 times the pitch P1 (shown in FIG. 2) of the outer crown lateral groove 15. desirable. In the present embodiment, the pitch P2 of the inner crown lateral groove 20 is the same as the pitch P1 of the outer crown lateral groove 15.

As shown in FIG. 1, in a more desirable embodiment, it is desirable that the inner crown lateral groove 20 does not intersect the region where the outer crown lateral groove 15 is projected along the tire axial direction. Such an arrangement of the inner crown lateral groove 20 suppresses a local decrease in rigidity of the tread portion 2. Therefore, when cornering on a dry road surface, the tread portion 2 is deformed so that the entire ground contact surface follows the road surface, and as a result, excellent ground contact performance and steering stability can be exhibited.

As shown in FIG. 4, the inner shoulder land portion 14 is divided between the inner tread ground contact end Ti and the inner main groove 6. It is desirable that the width W9 of the inner shoulder land portion 14 in the tire axial direction is smaller than, for example, the width W7 of the inner crown land portion 13 in the tire axial direction. Specifically, it is desirable that the width W9 of the inner shoulder land portion 14 is 0.20 to 0.35 times the tread half width TWh.

The inner shoulder land portion 14 is provided with, for example, a plurality of inner shoulder lateral grooves 25. The inner shoulder lateral groove 25 extends from the inner tread ground contact end and is interrupted within the inner shoulder land portion 14. The inner shoulder lateral groove 25 is arranged so as to cross the inner tread ground contact end Ti, and the outer end of the inner shoulder lateral groove 25 is located closer to the sidewall portion than the inner tread ground contact end Ti. Such an inner shoulder lateral groove 25 can enhance wet performance while maintaining the rigidity of the inner shoulder land portion 14.

The length L8 (the length from the inner tread ground contact end Ti to the inner end of the inner shoulder lateral groove 25) in the tread contact patch of the inner shoulder lateral groove 25 is, for example, the tire of the inner shoulder land portion 14. It is desirable that the width in the axial direction is 0.45 to 0.65 times the width W9. It is more desirable that the inner shoulder lateral groove 25 is interrupted on the inner main groove 6 side rather than the center position of the inner shoulder land portion 14 in the tire axial direction, for example.

It is desirable that the inner shoulder lateral groove 25 is arranged at an angle of 45 ° or less with respect to the tire axial direction, for example. The angle of the inner shoulder lateral groove 25 with respect to the tire axial direction is preferably 0 to 20 °, for example. Such an inner shoulder lateral groove 25 can maintain the lateral rigidity of the inner shoulder land portion 14, and thus can improve the cornering performance on a dry road surface.

It is desirable that the groove width W10 of the inner shoulder lateral groove 25 is smaller than, for example, the groove width W1 of the inner main groove 6. Further, it is desirable that the groove width W10 of the inner shoulder lateral groove 25 is larger than the groove width W8 of the inner crown lateral groove 20, for example. Specifically, it is desirable that the groove width W10 of the inner shoulder lateral groove 25 is, for example, 5.0 to 15.0 mm. Such an inner shoulder lateral groove 25 can improve wet performance while maintaining steering stability on a dry road surface.

FIG. 5 shows a sectional view taken along line BB of the inner shoulder lateral groove 25. As shown in FIG. 5, it is desirable that the depth d4 of the inner shoulder lateral groove 25 is smaller than, for example, the depth d1 of the inner main groove 6 (shown in FIG. 2).

It is desirable that the inner shoulder lateral groove 25 includes, for example, a chamfered portion 27 having a recessed corner portion between the groove edge 26e and the groove wall 26w. The angle θ2 of the chamfered portion 27 with respect to the tread normal passing through the groove edge 26e is, for example, 35 to 70 °, more preferably 60 to 70 °. Such a chamfered portion 27 is useful for suppressing uneven wear of the groove edge while improving the drainage property of the inner shoulder lateral groove 25.

As shown in FIG. 4, the pitch P3 in the tire circumferential direction of the two inner shoulder lateral grooves 25 adjacent to each other in the tire circumferential direction is, for example, 0.90 to 0.90 of the pitch P2 (shown in FIG. 2) of the inner crown lateral groove 20. It is desirable that it is 1.10 times. In the present embodiment, the pitch P3 of the inner shoulder lateral groove 25 is the same as the pitch P2 of the inner crown lateral groove 20.

As shown in FIG. 1, it is desirable that the inner shoulder lateral groove 25 does not intersect the region where the outer crown lateral groove 15 is projected along the tire axial direction, for example. Such an arrangement of the inner shoulder lateral groove 25 can suppress a local decrease in rigidity of the tread portion 2 and improve the steering cornering performance on a dry road surface.

In a more desirable embodiment, the groove center line of the inner shoulder lateral groove 25 is provided at a position different from the groove center line of the inner crown lateral groove 20 in the tire circumferential direction. However, a part of the inner shoulder lateral groove 25 may intersect with the region where the inner crown lateral groove 20 is projected along the tire axial direction. Such an inner shoulder lateral groove 25 can improve wet performance while suppressing an excessive decrease in rigidity of the inner tread portion 5.

Although the tire of one embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment described above, and may be modified into various embodiments.

A size 205 / 55R16 tire with the basic tread pattern of FIG. 1 was prototyped based on the specifications in Table 1. As a comparative example, the tire shown in FIG. 6 was prototyped. The tire of the comparative example has a main groove d having the same groove width as the inner main groove c arranged in the inner tread portion b in the outer tread portion a. Further, the outer tread portion a is not provided with a groove other than the main groove d. The pattern of the comparative example has the same configuration as the pattern of FIG. 1 in the region between the central main groove e and the inner tread ground contact end Ti. Wet performance and cornering performance on dry roads of each test tire were tested. The common specifications and test methods for each test tire are as follows.
Rim: 16 x 6.5J
Tire internal pressure: 230kPa

<Wet performance>
An inside drum tester was used, and the rate of occurrence of the hydroplaning phenomenon was measured when each test tire traveled on a drum surface at a depth of 5.0 mm under the following conditions. The result is an index with Comparative Example 1 as 100, and the larger the value, the higher the generation rate and the better the wet performance.
Slip angle: 1.0 °
Vertical load: 4.2kN

<Cornering performance on dry roads>
The cornering performance of the following test vehicle equipped with the above test tires when traveling on a circuit course on a dry road surface was evaluated by the driver's sensuality. The result is a score with a comparative example of 100, and the larger the value, the better the steering stability.
Test vehicle: Displacement 2000cc, rear-wheel drive vehicle Test tire mounting position: All-wheel test results are shown in Table 1.

As a result of the test, it was confirmed that the tire of the example had both cornering performance and wet performance on a dry road surface.

2 Tread part 6 Inner main groove 7 Outer narrow groove 8 Central main groove 11 Outer crown land part 15 Outer crown lateral groove Ti Inner tread ground contact end To Outer tread ground contact end C Tire equator

Claims (8)

A tire with a tread that is oriented to be mounted on a vehicle.
The tread portion is
The inner tread grounding end, which is inside the vehicle when mounted on the vehicle,
The outer tread grounding end, which is the outside of the vehicle when mounted on the vehicle,
An inner main groove that continuously extends in the tire circumferential direction between the inner tread ground contact end and the tire equator,
An outer narrow groove that extends continuously in the tire circumferential direction between the outer tread ground contact end and the tire equator and has a groove width smaller than that of the inner main groove.
A central main groove that continuously extends in the tire circumferential direction between the inner main groove and the outer fine groove,
It has an outer crown land portion divided between the central main groove and the outer narrow groove.
The outer crown land portion is provided with a plurality of outer crown lateral grooves having both ends interrupted within the outer crown land portion.
tire. The tread portion has an outer shoulder land portion partitioned between the outer tread ground contact end and the outer groove.
The tire according to claim 1, wherein the outer shoulder land portion is not provided with a lateral groove communicating with the outer fine groove. The tire according to claim 2, wherein the outer shoulder land portion is a plain rib having no groove. The tire according to any one of claims 1 to 3, wherein the groove width of the central main groove is larger than the groove width of the outer fine groove and smaller than the groove width of the inner main groove. The tread portion has an inner crown land portion divided between the inner main groove and the central main groove.
The tire according to any one of claims 1 to 4, wherein the inner crown land portion is provided with a plurality of inner crown lateral grooves extending from the inner main groove and interrupting the inner crown land portion. The tire according to claim 5, wherein the inner crown lateral groove does not intersect with a region where the outer crown lateral groove is projected along the tire axial direction. The tread portion has an inner shoulder land portion divided between the inner tread ground contact end and the inner main groove.
The tire according to any one of claims 1 to 6, wherein the inner shoulder land portion is provided with a plurality of inner shoulder lateral grooves extending from the inner tread ground contact end and interrupting the inner shoulder land portion. The tire according to claim 7, wherein the inner shoulder lateral groove does not intersect the region where the outer crown lateral groove is projected along the tire axial direction.

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