Patent ID: 12194782

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.FIG.1is a development view of a tread portion2of a motorcycle tire (hereafter, it may be simply referred to as “tire”.)1of an embodiment according to the present disclosure. The tire1according to the present embodiment may suitably be used for on-road driving such as on a dry asphalt road surface. Alternatively, the tire1according to the present disclosure is not limited to such an aspect.

The tread portion2, in the present embodiment, includes a crown portion Cr that is a region of 50% of a tread development width TWe centered on the tire equator C, and a first shoulder portion51that is an outer region of the crown portion Cr (left side of the crown portion Cr inFIG.1). In addition, the tread portion2includes a second shoulder portion S2that is located on the opposite side with respect to the first shoulder portion S1(right side of the crown portion Cr inFIG.1). The crown portion Cr is a region that comes into contact with the ground when traveling straight mainly. The first shoulder portion51and the second shoulder portion S2are regions that come into contact with the ground when turning. As used herein, the tread development width TWs is a distance in the tire axial direction between tread edges Te when the tread portion2is developed on a plane.

In the present embodiment, the tread portion2is provided with a plurality of first lateral grooves8. Each first lateral groove8includes a first groove portion11arranged in the crown portion Cr, a second groove portion12arranged in the first shoulder portion S1, and a third groove portion13connecting the first groove portion11and the second groove portion12. Since each first lateral groove8extends from the crown portion Cr to the first shoulder portion S1, each first lateral groove8can come into contact with the ground in a wide range from straight running to turning so as to improve drainage. In addition, since each first lateral groove8may be greater in axial length than a ground contact width when running, the air between the road surface and the groove may be discharged from the non-grounded area, improving noise resistance.

FIG.2Ais an enlarged view of one of the first lateral grooves8.FIG.2Bis a cross-sectional view taken along the line A-A ofFIG.1. As illustrated inFIGS.2A and2B, a groove depth D3and a groove width W3of the third groove portion13are respectively smaller than a groove depth D1and a groove width W1of the first groove portion11. Further, the groove depth D3and the groove width W3of the third groove portion13are respectively smaller than a groove depth D2and a groove width W2of the second groove portion12. Such a third groove portion13can suppress deformation of the first groove portion11and the second groove portion12during running to improve uneven wear resistance and vibration resistance. In addition, for wide tires1where a rubber thickness of the tread portion2tends to be small, the transient characteristics that is stability of handling during turning can be improved by providing the third groove portion13. As used herein, unless otherwise noted, the dimensions of portions of the tire are the values measured with the tire1under a normal state.

As used herein, the “normal state” is such that the tire1is mounted onto a standard wheel rim (not illustrated) with a standard internal pressure but loaded with no tire load.

As used herein, the “standard wheel rim” is a wheel rim officially approved for each tire by standards organizations on which the tire1is based, wherein the standard wheel rim is the “standard rim” specified in JATMA, the “Design Rim” in TRA, and the “Measuring Rim” in ETRTO, for example.

As used herein, the “standard internal pressure” is a standard internal pressure officially approved for each tire by standards organizations on which the tire1is based, wherein the standard internal pressure is the “maximum air pressure” in JATMA, the maximum pressure given in the “Tire Load Limits at Various Cold Inflation Pressures” table in TRA, and the “Inflation Pressure” in ETRTO, for example.

More than 80% of a tire axial length L3of the third groove portion13is located in the first shoulder portion S1. Thus, the rigidity of the first shoulder portion S1, which may receive a large camber thrust when cornering, can be maintained high, and vibration during running and uneven wear can be suppressed. Further, since the concentration of deflection in the tire1may be alleviated, the occurrence of cracks at the bottom of the groove can be suppressed. In the present embodiment, a 100% of the tire axial length L3of the third groove portion13is located in the first shoulder portion S1.

The tread portion2according to the present embodiment is preferably used for a front wheel tire of motorcycles. Alternatively, the tread portion2according to the present embodiment may be used for a rear wheel tire.

FIG.3illustrates a cross-sectional view taken along the line B-B ofFIG.1. As illustrated inFIG.3, in order to ensure a sufficient ground contact area when turning with large camber angles, the tread portion2of the tire1has a ground contact surface2athat is curved in an arc shape manner so as to be convex outward in the tire radial direction.

The tire1, for example, includes a carcass6extending between a pair of bead portions4and4, and a band layer7disposed outward in the tire radial direction of the carcass6in the tread portion2.

The carcass6, for example, includes two carcass plies6A and6B which are superimposed in the tire radial direction. The carcass plies6A and6B, for example, include carcass cords (not illustrated) oriented at an angle of from 30 to 45 degrees with respect to the tire circumferential direction, and thus the carcass6is configured as a bias structure. For the carcass plies6A and6B, well-known cord materials can be used. Tires with a bias structure have a characteristic that the rigidity of the tread portions2may be smaller and these are easier to deformed than tires1with a radial structure. In the present disclosure, it is possible to improve vibration resistance and uneven wear resistance not only in tires having a radial structure but also in tires having a bias structure by the above configuration.

The band layer7, in the present embodiment, includes a single band ply having a band cord (not illustrated) which is wound spirally at an angle of 5 degrees or less with respect to the tire circumferential direction. For the band ply, a well-known material can be used.

As illustrated inFIG.1, the tread portion2according to the present embodiment has a designated rotation direction N. In each first lateral groove8, the first groove portion11is located on a leading side than the second groove portion12with respect to the rotation direction N. Thus, in each first lateral groove8, the water under the tire1can smoothly be discharged from the tire equator C side to the tread edge Te side by the rotation of the tire1, and the drainage can be improved.

The first lateral grooves8, for example, are provided on both sides of the tire equator C. In the present embodiment, the left side first lateral grooves8and the right side first lateral grooves8are arranged alternately in the tire circumferential direction. The first lateral grooves8, in the present embodiment, do not cross the tire equator C. In other words, the first groove portions11are located so as not to cross the tire equator C. Such a layout can maintain the rigidity of the tread portion2around the tire equator C, which is subject to large ground pressure, and can maintain uneven wear resistance and vibration resistance. In the present specification, for grooves and sipes of the same shape arranged on both sides of the tire equator C, the grooves and sipes on the first shoulder portion S1are described, and the explanation of the grooves and sipes on the second shoulder portion S2is omitted.

As illustrated inFIG.2A, in each first lateral groove8, the first groove portion11, the second groove portion12and the third groove portion13, for example, are inclined in the same direction with respect to the tire axial direction. This makes the flow of water in each first lateral groove8smoother. Angles θ1, θ2and θ3with respect to the tire axial direction of the first groove portion11, the second groove portion12and the third groove portion13, respectively, are preferably in a range from 20 to 60 degrees. The absolute value of the difference among the angle θ1of the first groove portion11, the angle θ2of the second groove portion12and the angle θ3of the third groove portion13(|θ1−θ2|, |θ2−θ3|, and |θ3−θ1|) are preferably in a range of from 30 to 50 degrees. As used herein, each of the angles θ1, θ2and θ3is an average value of the maximum value and the minimum value of each of the first, second and third groove portions11,12and13, respectively.

In each first lateral groove8, the first groove portion11, for example, includes a first groove edge11elocated on a first side (below inFIG.2) in the tire circumferential direction and a second groove edge iii located on a second side (above inFIG.2) in the tire circumferential direction. The second groove edge11iof the first groove portion11, for example, includes a bent point F, and an angle of the second groove edge11iwith respect to the tire axial direction changes locally via the bent point F. The second groove edge11iincludes an outer portion15located outward in the tire axial direction of the bent point F, and an inner portion16located inward in the tire axial direction of the bent point F. The first groove edge11eof the first groove portion11extends smoothly without having a bent portion. The first groove edge11eand the second groove edge11i, for example, are connected to an inner end8iof the first lateral groove8. The inner end8i, in the present specification, is the innermost end in the tire axial direction of the groove centerline8cof the first lateral groove8. In addition, the inner end8iincludes an arc portion having a radius of curvature r of equal to or less than 2 mm in this specification.

The first groove edge11eand the outer portion15, for example, include arc portions R extending in an arc shape manner so as to be convex in one direction in the tire circumferential direction. The arc portions R of the first groove edge11eand the outer portion15, in the present embodiment, protrude toward the rearward with respect to the rotation direction N. The inner portion16according to the present embodiment extends straight.

FIG.4illustrates an enlarged view of one of the first lateral grooves8. As illustrated inFIG.4, in each first lateral groove8, an angle α1with respect to the tire axial direction of the inner portion16is greater than an angle α2with respect to the tire axial direction of the first groove edge11e. Thus, the first groove portion11formed by the inner portion16has a groove width w tapering toward the inner end8i. Such a first groove portion11can smoothly guide water and air into the first groove portion11utilizing the rotation of the tire1while suppressing the decrease in rigidity of the crown portion Cr.

The second groove portion12, for example, includes a first groove edge12elocated on the first side in the tire circumferential direction and a second groove edge12ilocated on the second side in the tire circumferential direction. The first groove edge12eand the second groove edge12i, for example, include arc portions R extending in an arc shape manner so as to be convex in one direction (the first side) in the tire circumferential direction. The arc portions R of the first groove edge12eand the second groove edge12i, in the present embodiment, protrude toward rearward with respect to the rotation direction N.

The third groove portion13is arranged nearer to the second groove edge11iof the first groove portion11than the first groove edge11eof the first groove portion11, and is arranged nearer to the first groove edge12eof the second groove portion12than the second groove edge12iof the second groove portion12. In other words, in each first lateral groove8according to the present embodiment, a virtual line12kin which the groove centerline12cof the second groove portion12is expanded inward smoothly in the tire axial direction is located on the rearward than the third groove portion13in the rotation direction N. This feature may help to suppress cracks on the groove bottom of the first lateral groove8.

The third groove portion13, for example, includes a first groove edge13elocated on the first side in the tire circumferential direction and a second groove edge13ilocated on the second side in the tire circumferential direction. The first groove edge13eof the third groove portion13, for example, includes a crank-shaped portion K that extends in a crank shape manner toward the first groove edge11eof the first groove portion11. The second groove edge13iof the third groove portion13, for example, includes an arc portion R that is convex on the opposite side to the convex of the second groove edge11iof the first groove portion11.

In the present embodiment, the groove width w of the third groove portion13suddenly decreases between the first groove portion11and the second groove portion12. Preferably, a ratio of the change of the groove width w to a unit length of the groove is equal to or more than 0.4.

As illustrated inFIG.2A, in each first lateral groove8, the groove width W3of the third groove portion13is preferably equal to or more than 15% of the groove widths W1and W2of the first groove portion11and the second groove portion12, respectively, more preferably equal to or more than 20%, but preferably equal to or less than 50% of the groove widths W1and W2, more preferably equal to or less than 45%. When the groove width W3of the third groove portion13is equal to or more than 15% of the groove widths W1and distorted W2of the first groove portion11and the second groove portion12, respectively, drainage can be ensured. When the groove width W3of the third groove portion13is equal to or less than 50% of the groove widths W1and distorted W2of the first groove portion11and the second groove portion12, respectively, uneven wear resistance and vibration resistance can be improved. Note that in each first lateral groove8, the groove width W3of the third groove portion13means the minimum groove width of the third groove portion13. Further, note that in each first lateral groove8, the groove widths W1and W2of the first groove portion11and the second groove portion12are the maximum groove width of the first groove portion11and the maximum groove width of the second groove portion12, respectively. Although not particularly limited, the groove width W1of each first groove portion11is in a range from 3.5 to 7.0 mm.

As illustrated inFIG.2B, from a similar point of view, in each first lateral groove8, the groove depth D3of the third groove portion13is preferably equal to or more than 15% of the groove depths D1and D2of the first groove portion11and the second groove portion12, respectively, more preferably equal to or more than 20%, but preferably equal to or less than 50% of the groove depths D1and D2of the first groove portion11and the second groove portion12, respectively, more preferably equal to or less than 45%. Note that in each first lateral groove8, the groove depth D3of the third groove portion13means the minimum groove depth of the third groove portion13. Further, note that in each first lateral groove8, the groove depths D1and D2of the first groove portion11and the second groove portion12, respectively, are the maximum groove depths of the first groove portion11and the maximum groove depth of the second groove portion12, respectively. Although not particularly limited, the groove depth D1of each first groove portion11is in a range from 3.0 to 7.5 mm.

As illustrated inFIG.2A, the length L3in the tire axial direction of the third groove portion13is preferably equal to or more than 10% of a development length Ws (shown inFIG.1) in the tire axial direction of the first shoulder portion S1, more preferably, equal to or more than 15%, but preferably equal to or less than 30% of the development length Ws, more preferably equal to or less than 25%.

Each first lateral groove8, for example, further includes a fourth groove portion14extending outward in the tire axial direction from the second groove portion12. A groove width W4of the fourth groove portion14is smaller than the groove widths W1and W2of the first groove portion11and the second groove portion12, respectively. Further, a groove depth D4of the fourth groove portion14is smaller than the groove depths D1and D2of the first groove portion11and the second groove portion12, respectively. Such a fourth groove portion14can also enhance drainage and suppress uneven wear resistance and deterioration of vibration resistance. The fourth groove portion14can come into contact with the ground during turning with large camber angles. Hence, by setting the groove depth D4and the groove width W4of the fourth groove portion14small as described above, the reduction in rigidity of the ground contact surface2acan be prevented. Thus, a rider of a motorcycle during turning with large camber angles can return the motorcycle smoothly to straight running condition. Therefore, handling of motorcycle can be lighter. In the present embodiment, the fourth groove portion14is greater in axial length than the third groove portion13, and the fourth groove portion is smaller in angle with respect to the tire axial direction than the third groove portion.

In the present embodiment, the groove depth D4and the groove width W4of the fourth groove portion14, for example, are substantially the same as the groove depth D3and the groove width W3of the third groove portion13, respectively. Such a fourth groove portion14can effectively exert the above-mentioned effects. The above-mentioned “substantially the same” means that the difference between the groove depth D4of the fourth groove portion14and the groove depth D3of the third groove portion13is within 2 mm. It also means that the difference between the groove width W4of the fourth groove portion14and the groove width W3of the third groove portion13is within 2 mm.

Each fourth groove portion14, in the present embodiment, is inclined in the same direction as the inclination direction of the second groove portion12with respect to the tire circumferential direction. Such a fourth groove portion14can maintain smooth water flow in the first lateral groove8.

An outer end14ain the tire axial direction of each fourth groove portion14is located within the first shoulder portion S1. In other words, each fourth groove portion14terminates within the first shoulder portion S1so as not to traverse the tread edge Te. Such a fourth groove portion14can suppress the decrease in rigidity of the tread portion2on the tread edge Te on which a large lateral force acts.

In each first lateral groove8, the fourth groove portion14is arranged nearer to the second groove edge12iof the second groove portion12than the first groove edge12eof the second groove portion12. Each fourth groove portion14includes a first groove edge14eon the first side in the tire circumferential direction and a second groove edge14ilocated on the second side in the tire circumferential direction. The second groove edge14iof the fourth groove portion14is connected to the second groove edge12iof the second groove portion12so as to form a single circular arc. The first groove edge14eof the fourth groove portion14includes a crank-shaped portion K extending in a crank shape manner and connected to the second groove edge12eof the second groove portion12.

As illustrated inFIG.2B, a groove bottom11sof the first groove portion11and a groove bottom13sof the third groove portion13are smoothly connected. A groove bottom12sof the second groove portion12and a groove bottom13sof the third groove portion13are smoothly connected. Further, the groove bottom12sof the second groove portion12and a groove bottom14sof the fourth groove portion14are smoothly connected. Such a first lateral groove8can suppress the occurrence of cracks at the groove bottoms and smooth the flow of water in the groove. The above-mentioned “smoothly connected” means that each connected portion among the groove bottoms11s,13s,12s, and14sincludes an inner arc portion17awhich is convex inward in the tire radial direction, and an outer arc portion17bwhich is convex outward in the tire radial direction and is located outward in the tire radial direction than the inner arc portion17a.

As illustrated inFIG.1, the tread portion2, for example, is provided with a circumferential groove20, a plurality of second lateral grooves21, a plurality of third lateral grooves22, and a plurality of sipes23. As used herein, the grooves such as the first lateral grooves8and the circumferential groove20are voids that have a maximum groove width greater than 1.5 mm. As used herein, “sipe” means an incision that has a maximum width equal to or less than 1.5 mm.

The circumferential groove20, for example, extends continuously in the tire circumferential direction on the tire equator C. The circumferential groove20according to the present embodiment extends in a zigzag manner which includes first portions20A inclined in a first direction (downward left inFIG.1) with respect to the tire circumferential direction and second portions20B inclined in the opposite direction to the first portions20A with respect to the tire circumferential direction.

The circumferential groove20includes a pair of groove edges20eand20e. Since the circumferential groove20extends on the tire equator C in a zigzag manner, each of the pair of groove edges20eincludes outer portions25located outward in the tire axial direction than the other groove edge, and inner portions26located inward in the tire axial direction than the other groove edge, wherein the outer portions25and the inner portions26are arranged alternately in the tire circumferential direction. In connecting portions between the first portions20A and the second portions20B, the outer portions25are configured to include axial portions J that extend in the tire axial direction. Such an axial portion J can collect water under the ground contact surface2ainto the circumferential groove20to improve drainage.

In the present embodiment, the second lateral grooves21, the third lateral grooves22and the sipes23are arranged on both sides of the tire equator C. The second lateral grooves21, the third lateral grooves22and the sipes23, for example, are inclined rearward in the rotation direction N toward the respective tread edges Te. In the present embodiment, the second lateral grooves21, the third lateral grooves22and the sipes23are curved in an arc manner so as to be convex rearward in the rotation direction N. The second lateral grooves21, the third lateral grooves22and the sipes23, for example, terminate without reaching the tread edges Te.

On the left side of the tire equator C, the second lateral grooves21, for example, extend from the crown portion Cr to the first shoulder portion S1. In the present embodiment, the second lateral grooves21have a length in the tire axial direction greater than that of the first lateral grooves8. Inner ends21iin the tire axial direction of the second lateral grooves21, for example, are located nearer to the tire equator C than the inner ends8iof the first lateral grooves8.

On the left side of the tire equator C, the third lateral grooves22, for example, extend from the crown portion Cr to the first shoulder portion S1. The third lateral grooves22have a length in the tire axial direction smaller than that of the first lateral grooves8. Axial inner ends22iof the third lateral grooves22are located nearer to the tread edge Te than the inner ends8iof the first lateral grooves8. Axial outer ends22eof the third lateral grooves22are located nearer to the tire equator C than the outer ends8e(shown inFIG.4) of the first lateral grooves8.

On the left side of the tire equator C, as illustrated inFIG.4, the sipes23are arranged in the first shoulder portion S1. Inner ends23iin the tire axial direction of the sipes23are located within the first shoulder portion S1. Outer ends23ein the tire axial direction of the sipes23are, in the tire axial direction, arranged between the outer ends8eof the first lateral grooves8and the outer ends22eof the third lateral grooves22.

FIG.5illustrates a development view of the tread portion2in accordance with another embodiment. The same elements which have already explained in the above embodiment are designated by the same reference numerals and the description thereof may be omitted. In this embodiment, the tread portion2is preferably used for rear wheel tires of motorcycles. Alternatively, the tread portion2may be used for front wheel tires.

As illustrated inFIG.5, the tread portion2according to the present embodiment includes the first lateral grooves8, the second lateral grooves21, the third lateral grooves22and the sipes23. The tread portion2according to this embodiment is not provided with any circumferential grooves. As to the sipes23, for example, a set of two sipes are provided in each region between one of the first lateral grooves8and one of the second lateral grooves21which are directly adjacent in the tire circumferential direction.

In this embodiment, the inner ends21iof the second lateral grooves21are located inward in the tire axial direction than the inner ends21iof the second lateral grooves21of the previous embodiment. This can suppress the deterioration of drainage. The shortest distance Lb between the inner ends21iof the second lateral grooves21and the tire equator C is preferably equal to or more than 0.5%, more preferably equal to or more than 0.7%, of a development width We of the crown portion Cr, but preferably equal to or less than 2.0%, more preferably equal to or less than 2.5% of the width Ws.

Motorcycles include front wheel tires and rear wheel tires (not illustrated). Rear wheel tires are not significantly affected by the rider's steering wheel operation. For such tires, grip performance is more important than handling performance. Thus, it is preferable that a land ratio of the tread portion2of the rear wheel tires is larger than a land ratio of the tread portion2of the front wheel tire. In particular, a land ratio of the tread portion2of rear wheel tires is preferably equal to or more than 80%.

Although some particularly preferable embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the embodiments shown in drawings.

Working Example

Motorcycle tires with the basic tread pattern ofFIG.1was prepared. Then, handling performance, drainage performance, uneven wear resistance, durability, vibration resistance, and noise resistance of each test tire were tested. The common specifications and test methods for each sample tire are as follows.

Handling Performance, Uneven Wear Resistance, Durability, Vibration Resistance, Noise Resistance Test:

Each test tire was mounted on the front wheel of a motorcycle (displacement 1500 cc) under the following conditions. The same tire with a tread pattern was used for the rear wheel tire. Then, a test rider drove the motorcycle on a dry asphalt road surface, and lightness of handling, degree of vibration and noise at that time were evaluated by the sensuality of the test rider. In addition, occurrence of uneven wear after running and the occurrence of cracks on the bottoms of grooves were checked. The test results are shown in Table 1 using scoring with Ref 1 as 100. Each performance is better when the numerical value is larger, wherein 95 or more is passed.

Front Tire Specifications (Size, Rim, Internal Pressure):

110/70-13M/C, 13×3.00MT, 200 kPa

Rear Wheel Tire Specifications (Size, Rim, Internal Pressure):

130/70-13M/C, 13×3.50MT, 225 kPa

Drainage Test:

Using the above motorcycle, the test rider drove the motorcycle on a wet asphalt road surface, and the ease of running at that time was evaluated by the sensuality of the test rider. The test results are shown in Table 1 using a score with Ref 1 as 100. The larger the value, the better the drainage property, wherein 95 or more is passed.

Table 1 shows the test results.

In Table 1, “A” represents that the positions of the second groove portions are at the positions shown inFIG.1.

“B” represents that the second groove portions are located in the crown portion.

“C” represents that the positions of the third groove portions are at the positions shown inFIG.1.

“D” represents that the third groove portions are located in the crown portion.

“E” represents that 80% of the length of each third groove portion is located in the first shoulder portion.

“F” represents that 70% of the length of each third groove portion is located in the first shoulder portion.

“G” represents that the bottoms of the groove portions of each first lateral groove is configured as the embodiment shown inFIG.2B.

“H” represents that the bottoms of the groove portions of each first lateral groove are connected in a straight-line shape.

“I” represents that the inner portion of each first groove portion is in the aspect ofFIG.1.

“J” represents that the inner portion of each first groove portion extends with a constant width.

The lengths of the third groove portions are all the same.

TABLE 1Ref. 1Ref. 2Ref. 3Ex. 1Ex. 2Ex. 3Ex. 4Ex. 6Ex. 6Ex. 7Ref. 4Locations of second grooveBAAAAAAAAAAportions of first lateralgroovesLocations of third grooveCCDCCCCCCEFportionsL3 (%)0100100100100100100100100100100D3/D1 (%)25100252525502525252525W3/W1 (%)2525252525502525252525Fourth groove portionsappliedappliedappliedappliednoneappliedappliedappliedappliedappliedappliedD4/D1 (%)25252525—255025252525Shapes of groove bottomsGGGGGGGHGGGof first lateral groovesShapes of inner portionsIIIIIIIIJIIof first groove portionsHandling performance100100951009595100100100100100[score: Larger is better.]Uneven wear resistance1009590105105100100959510090[score: Larger is better.]Durability100951001001051001009595100100[score: Larger is better.]Vibration resistance100909510510510510010010010595[score: Larger is better.]Noise resistance100105105100100100100105105100100[score: Larger is better.]Drainage performance100115110110105115115115115110105[score: Larger is better.]

As a result of the tests, it is understood that the tires of example have improved drainage performance without impairing the uneven wear resistance and vibration resistance as compared with the tires of comparative example.

The following additional notes are disclosed regarding the above-described embodiments.

[Additional Note 1]

A motorcycle tire comprising:a tread portion comprising a crown portion that is a region of 50% of a tread development width centered on a tire equator, a first shoulder portion that is an outer region of the crown portion, and a plurality of first lateral grooves,each of the plurality of first lateral grooves comprising a first groove portion arranged in the crown portion, a second groove portion arranged in the first shoulder portion, and a third groove portion connecting the first groove portion and the second groove portion,
whereina groove depth and a groove width of the third groove portion are respectively smaller than a groove depth and a groove width of the first groove portion,the groove depth and the groove width of the third groove portion are respectively smaller than a groove depth and a groove width of the second groove portion, andmore than 80% of a tire axial length of the third groove portion is located in the first shoulder portion.
[Additional Note 2]

The motorcycle tire according to Additional note 1, wherein in each of the plurality of first lateral grooves, the first groove portion does not cross the tire equator.

[Additional Note 3]

The motorcycle tire according to Additional note 1 or 2, wherein in each of the plurality of first lateral grooves, the first groove portion, the second groove portion and the third groove portion are inclined in a same direction with respect to the tire axial direction.

[Additional Note 4]

The motorcycle tire according to any one of Additional notes 1 to 3, wherein in each of the plurality of first lateral grooves, the groove width of the third groove portion is in a range from 15% to 50% of the groove width of the first groove portion and the groove width of the second groove portion.

[Additional Note 5]

The motorcycle tire according to anyone of Additional notes 1 to 4, wherein in each of the plurality of first lateral grooves, the groove depth of the third groove portion is in a range from 15% to 50% of the groove depth of the first groove portion and the groove depth of the second groove portion.

[Additional Note 6]

The motorcycle tire according to any one of Additional notes 1 to 5, wherein in each of the plurality of first lateral grooves,the first groove portion comprises a first groove edge located on a first side in a tire circumferential direction and a second groove edge located on a second side in the tire circumferential direction,the second groove portion comprises a first groove edge located on the first side in the tire circumferential direction and a second groove edge located on the second side in the tire circumferential direction, andthe third groove portion is arranged nearer to the second groove edge of the first groove portion than the first groove edge of the first groove portion, and is arranged nearer to the first groove edge of the second groove portion than the second groove edge of the second groove portion.
[Additional Note 7]

The motorcycle tire according to any one of Additional notes 1 to 6, whereineach of the plurality of first lateral grooves further comprises a fourth groove portion extending outward in the tire axial direction from the second groove portion, anda groove depth and a groove width of the fourth groove portion is respectively smaller than the groove depths and the groove widths of the first groove portion and the second groove portion, respectively.
[Additional Note 8]

The motorcycle tire according to Additional note 7, whereinin each of the plurality of first lateral grooves,the first groove portion, the second groove portion, the third groove portion, and the fourth groove portion are inclined in a same direction with respect to the tire axial direction.
[Additional Note 9]

The motorcycle tire according to any one of Additional notes 1 to 8, whereinthe tread portion has a designated rotation direction, andthe first groove portion is located on a leading side than the second groove portion with respect to the rotation direction.
[Additional Note 10]

The motorcycle tire according to any one of Additional notes 1 to 9, further comprising a carcass having a bias structure.

[Additional Note 11]

A set of motorcycle tires comprising:a motorcycle tire for front wheel according to any one of Additional notes 1 to 10, anda motorcycle tire for rear wheel according to any one of Additional notes 1 to 10,whereina land ratio of the motorcycle tire for rear wheel is greater than a land ratio of the motorcycle tire for front wheel.