JP2016199179A - Tire for racing cart - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire for a racing cart that allows tread rubber to generate heat to an appropriate temperature at an early stage while improving steering stability performance.SOLUTION: A tire for a racing cart is provided with a tread part 2.The tread part 2 includes a plurality of crown blocks 3 arranged in a tire circumferential direction on a tire equator C, and a plurality of shoulder blocks 4 arranged in the tire circumferential direction on both outer sides of the plurality of crown blocks 3. Each of the crown blocks 3 has a horizontally long shape in which a maximum length L2 in a tire axial direction is larger than a maximum length L1 in the tire circumferential direction. The maximum length L2 of each crown block 3 in the tire axial direction falls within a range of 30-60% of a tread width TW.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a racing cart tire having improved steering stability performance and warming performance.

  Conventionally, various tires for racing carts with improved wet grip performance have been proposed. For example, in Patent Document 1, a racing cart air including a plurality of crown blocks arranged in the tire circumferential direction on the tire equator and a plurality of shoulder blocks arranged in the tire circumferential direction on both outer sides of the crown block. Entered tires have been proposed.

JP 2014-177238 A

  In the racing cart tire, in order to improve the steering stability performance, it is generally effective to increase the rigidity in the tire axial direction of the tread portion in the vicinity of the tire equator having a high contact pressure.

  However, in the tire disclosed in Patent Document 1, since the maximum length in the tire circumferential direction is equal to the maximum length in the tire axial direction, the rigidity of the crown block in the tire axial direction may be insufficient. There is.

  In addition, since deformation of the crown block in the tire circumferential direction is suppressed, heat generation of the tread rubber is suppressed during straight travel. For this reason, there exists a possibility that a tread rubber may become difficult to warm to the appropriate temperature which exhibits desired performance.

  The present invention has been devised in view of the actual situation as described above, and has as its main purpose to provide a racing cart tire that can quickly heat a tread rubber to an appropriate temperature while improving steering stability performance. Yes.

  The present invention relates to a racing cart tire having a tread portion, wherein the tread portion includes a plurality of crown blocks arranged in the tire circumferential direction on the tire equator, and both outer sides of the crown blocks. A plurality of shoulder blocks arranged in a direction, each crown block having a horizontally long shape having a maximum length in the tire axial direction larger than a maximum length in the tire circumferential direction, and the tire block direction of the crown block The maximum length is 30 to 60% of the tread width.

  In the racing cart tire according to the present invention, it is preferable that the crown block has a trapezoidal tread surface.

  In the racing cart tire according to the present invention, it is desirable that the tread surface of the crown block includes an upper bottom having an angle of 80 ° to 100 ° with respect to the tire circumferential direction.

  In the racing cart tire according to the present invention, it is desirable that the tread surface of the crown block includes a lower bottom having an angle of 80 ° to 100 ° with respect to the tire circumferential direction.

  In the racing cart tire according to the present invention, the inner portion of the shoulder block in the tire axial direction is in contact with the lower bottom of the crown block or faces through a narrow groove having a width of 2 mm or less. It is desirable to include.

  In the racing cart tire according to the present invention, it is desirable that the length of the protruding portion in the tire axial direction is 2 to 10% of the tread width.

  In the racing cart tire according to the present invention, the shoulder block includes a plurality of first shoulder blocks arranged on the right side of the crown block and a plurality of second shoulder blocks arranged on the left side of the crown block. And the protrusion includes a first protrusion provided on the first shoulder block and a second protrusion provided on the second shoulder block, the first protrusion and the second protrusion. It is desirable that the portions are provided alternately in the tire circumferential direction.

  In the racing cart tire according to the present invention, the tread portion includes a crown inclined groove extending between the crown block and the shoulder block, and a shoulder block having one end connected to the crown inclined groove and arranged in the tire circumferential direction. It is desirable that a shoulder inclined groove extending between the two and reaching the tread end is provided.

  In the racing cart tire according to the present invention, the land ratio of the shoulder region that is a quarter of the tread width from the tread end is that of the crown region that is a half of the tread width around the tire equator. It is desirable to be larger than the land ratio.

  The tread portion of the racing cart tire of the present invention comprises a plurality of crown blocks arranged in the tire circumferential direction on the tire equator and a plurality of shoulder blocks arranged in the tire circumferential direction on both outer sides of the crown block. Including. Each crown block has a horizontally long shape in which the maximum length in the tire axial direction is larger than the maximum length in the tire circumferential direction. Thereby, the rigidity in the tire axial direction of the tread portion in the vicinity of the tire equator is increased, and the steering stability performance is improved. Further, the rigidity of the crown block in the tire circumferential direction is relatively lowered, and the crown block is appropriately deformed when going straight, so that heat generation of the tread rubber is promoted. Thereby, the warming performance of the tire is improved.

  The maximum length of the crown block in the tire axial direction is 30 to 60% of the tread width. As a result, when the lateral force from the road surface is received while securing the rigidity of the entire crown block, the end edge of the block is easily deformed appropriately, and the contact area increases. Accordingly, the grip performance during cornering is improved and the steering stability performance is enhanced.

It is an expanded view of the tread part of one Embodiment of the tire for racing carts of this invention. It is an enlarged view of the crown block of the tread part of FIG. It is the figure which showed typically the shape at the time of the cornering of the crown block of FIG. It is an enlarged view of the 1st shoulder block of the tread part of FIG. It is an enlarged view of the 2nd shoulder block of the tread part of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a development view of a tread portion 2 of a racing cart tire (not shown) of the present embodiment. As shown in FIG. 1, the racing cart tire of the present embodiment includes a tread portion 2.

  The tread portion 2 includes a plurality of crown blocks 3 and a plurality of shoulder blocks 4. The shoulder block 4 is disposed on both outer sides of the crown block 3.

  The crown block 3 includes a plurality of first crown blocks 11 and a plurality of second crown blocks 21. The first crown block 11 and the second crown block 21 are alternately arranged on the tire equator C in the tire circumferential direction.

  FIG. 2 is an expanded view of the crown blocks 11 and 21. Each of the crown blocks 11 and 21 has a horizontally long shape in which the maximum length L2 in the tire axial direction is larger than the maximum length L1 in the tire circumferential direction.

  As a result, the rigidity in the tire axial direction of the tread portion 2 in the vicinity of the tire equator C is enhanced, and the grip performance during cornering is improved. Further, the rigidity in the tire circumferential direction of the crown blocks 11 and 21 is relatively lowered, and the crown blocks 11 and 21 are appropriately deformed when going straight, so that heat generation of the tread rubber is promoted. Thereby, the warming performance of the tread part 2 improves.

  In the present embodiment, the maximum length L2 of the crown blocks 11 and 21 in the tire axial direction is 30 to 60% of the tread width TW shown in FIG.

  The tread width TW is a distance in the tire axial direction between the first tread end Te1 on one side and the second tread end Te2 on the other side.

  The first tread end Te1 and the second tread end Te2 are treads measured on a front wheel tire that is mounted on a rim having a rim width of 4.5 inches, an air pressure of 100 kPa, and a load load of 0.45 kN. This is the ground end. In the rear wheel tire, the first tread end Te1 and the second tread end Te2 are mounted on a rim having a rim width of 6.5 inches, the tread measured under the conditions of an air pressure of 100 kPa and a load load of 0.65 kN. This is the ground end.

  FIG. 3 is a diagram schematically showing the first crown block 11 when receiving a lateral force Fy from the road surface R by cornering. (A) Crown block 11 with length L2 less than 30% of tread width TW, (b) Crown block 11 with length L2 exceeding 60% of tread width TW, (c) Length L2 with tread width The crown blocks 11 of 30 to 60% of TW are shown respectively.

  As shown in FIG. 3A, in the crown block 11 having a length L2 of less than 30% of the tread width TW, the rigidity in the tire axial direction is insufficient as a whole of the crown block 11, and response performance and grip performance during steering are insufficient. May decrease.

  On the other hand, as shown in FIG. 3B, in the crown block 11 in which the length L2 exceeds 60% of the tread width TW, the rigidity of the crown block 11 in the tire axial direction becomes excessive. Therefore, when receiving the lateral force Fy from the road surface R, there is a possibility that the effect of increasing the ground contact area due to the deformation of the end edge portion 11Z of the crown block 11 cannot be expected sufficiently. In addition, the deformation of the crown block 11 in the tire axial direction is insufficient, which may affect the warming performance.

  On the other hand, in this embodiment, as shown in FIG. 3C, the length L2 of the crown block 11 is set in a range of 30 to 60% of the tread width TW. For this reason, when the lateral force Fy from the road surface R is received while securing the rigidity of the entire crown block 11 in the tire axial direction, the end edge portion 11Z of the block is easily deformed appropriately, and the contact area increases. Accordingly, the grip performance during cornering is improved and the steering stability performance is enhanced.

  The first crown block 11 has been described with reference to FIG. 3, but the same applies to the second crown block 21.

  The maximum length L1 in the tire circumferential direction of each crown block 11, 21 is, for example, preferably 10-20 mm, and more preferably 10-15 mm.

  When the length L1 is less than 10 mm, the rigidity of the crown blocks 11 and 21 in the tire circumferential direction is insufficient, and the braking performance and traction performance may be deteriorated. On the other hand, when the length L1 exceeds 20 mm, the rigidity of the crown blocks 11 and 21 in the tire circumferential direction becomes excessive, the deformation of the crown blocks 11 and 21 at the time of straight traveling is insufficient, and the warming performance of the tread portion 2 is affected. There is a risk.

  The treads 11S and 21S of the crown blocks 11 and 21 have a trapezoidal shape symmetrical to a line parallel to the tire equator C. The crown blocks 11 and 21 having such trapezoidal treads 11S and 21S have excellent drainage performance by designating the rotation direction of the tread portion 2. The tops of the tread surfaces 11S and 21S of the crown blocks 11 and 21 may be appropriately rounded or chamfered to reduce stress concentration and suppress damage such as chipping. The corner rounding radius at the top of the treads 11S and 21S is preferably, for example, 3.0 mm or less.

  The tread surface 11S of the first crown block 11 includes an upper base 11u and a lower base 11b. The angle δ1 of the upper bottom 11u with respect to the tire circumferential direction is preferably 80 ° to 100 °. The first crown block 11 having such an upper bottom 11u has high tire axial rigidity, and effectively enhances response performance and grip performance during steering. On the other hand, the angle δ2 of the lower bottom 11b with respect to the tire circumferential direction is preferably 80 ° to 100 °. The crown block 11 having the lower bottom 11b has high tire axial rigidity, and effectively enhances response performance and grip performance during steering. When the angles δ1 and δ2 are less than 80 ° or more than 100 °, the rigidity of the crown block 11 in the tire circumferential direction may be excessive. As a result, deformation of the crown block 11 during straight travel is suppressed, which may affect the heat generation of the tread rubber.

  Similarly, the tread surface 21S of the second crown block 21 includes an upper base 21u and a lower base 21b. The angle δ3 of the upper bottom 21u with respect to the tire circumferential direction is desirably 80 ° to 100 °, and the angle δ4 of the lower bottom 21b with respect to the tire circumferential direction is desirably 80 ° to 100 °. The crown block 21 having the upper base 21u and the lower base 21b has high rigidity in the tire axial direction, and effectively improves response performance and grip performance during steering. If the angles δ3 and δ4 are less than 80 ° or more than 100 °, the rigidity of the crown block 21 in the tire circumferential direction may be excessive. As a result, deformation of the crown block 21 during straight travel is suppressed, and there is a possibility that the heat generation of the tread rubber may be affected.

  As shown in FIG. 1, the shoulder block 4 includes a plurality of first shoulder blocks 12 and a plurality of second shoulder blocks 22. The first shoulder block 12 is arranged on the right side of the crown blocks 11 and 21 in the tire circumferential direction. The second shoulder block 22 is arranged on the left side of the crown blocks 11 and 21 in the tire circumferential direction.

  FIG. 4 is an expanded view of the first shoulder block 12. The tread 12S of the first shoulder block 12 is formed in a substantially trapezoidal shape. The top portion of the tread surface 12S of the first shoulder block 12 may be appropriately rounded or chamfered to reduce stress concentration and suppress damage such as chipping. The radius of rounding at the top of the tread 12S is preferably, for example, 3.0 mm or less.

  A first protrusion 12 </ b> P that protrudes in the tire circumferential direction is formed on the inner side of the first shoulder block 12 in the tire axial direction. It is desirable that the first protrusion 12P faces the lower bottom 11b of the first crown block 11 via the first narrow groove 70. The width of the first narrow groove 70 is desirably 2 mm or less, for example. The first narrow groove 70 is closed when the vehicle is decelerated, and the first crown block 11 and the first shoulder block 12 adjacent to each other in the tire circumferential direction support each other. Thereby, the rigidity in the tire circumferential direction of the tread portion 2 is increased, and the braking performance of the racing cart tire 1 is improved.

  The first protrusion 12 </ b> P may be in contact with the lower bottom 11 b of the first crown block 11. In this case, the first crown block 11 and the first shoulder block 12 constitute a continuous first land portion 10. By such a first protrusion 12P, the rigidity in the tire circumferential direction of the tread portion 2 is further increased, and the traction performance and the brake performance of the racing cart tire 1 are improved.

  The length L3 of the first protrusion 12P in the tire axial direction is desirably 2 to 10% of the tread width TW. When the length L3 is less than 2% of the tread width TW, the effect of supporting the crown block 11 and the shoulder block 12 that are adjacent to each other in the tire circumferential direction is reduced, and the rigidity in the tire circumferential direction of the tread portion 2 is sufficient. There is a risk that it cannot be raised.

  On the other hand, when the length L3 exceeds 10% of the tread width TW, the rigidity in the tire circumferential direction may become excessive due to the action of the first crown block 11 and the first shoulder block 12 adjacent to each other in the tire circumferential direction supporting each other. There is. As a result, deformation of the first crown block 11 and the first shoulder block 12 during straight travel is suppressed, and there is a possibility that the heat generation of the tread rubber may be affected.

  FIG. 5 is an expanded view of the second shoulder block 22. The tread surface 22S of the second shoulder block 22 is formed in a substantially trapezoidal shape. The top portion of the tread surface 22S of the second shoulder block 22 may be appropriately rounded or chamfered to reduce stress concentration and suppress damage such as chipping. The radius of rounding at the top of the tread 22S is preferably, for example, 3.0 mm or less.

  A second projecting portion 22 </ b> P projecting in the tire circumferential direction is formed on the inner side in the tire axial direction of the second shoulder block 22. It is desirable that the second protrusion 22P faces the lower bottom 21b of the second crown block 21 through the second narrow groove 80. The width of the second narrow groove 80 is preferably 2 mm or less, for example. The second narrow groove 80 is closed when the vehicle is decelerated, and the second crown block 21 and the second shoulder block 22 that are adjacent to each other in the tire circumferential direction support each other. Thereby, the rigidity in the tire circumferential direction of the tread portion 2 is increased, and the braking performance of the racing cart tire 1 is improved.

  The second protrusion 22P may be in contact with the lower bottom 21b of the second crown block 21. In this case, the second crown block 21 and the second shoulder block 22 constitute a continuous second land portion 20. By such a second protrusion 22P, the rigidity in the tire circumferential direction of the tread portion 2 is further enhanced, and the traction performance and the brake performance of the racing cart tire 1 are improved.

  The length L4 of the second protrusion 22P in the tire axial direction is desirably 2 to 10% of the tread width TW. When the length L4 is less than 2% of the tread width TW, the effect of supporting the second crown block 21 and the second shoulder block 22 adjacent to each other in the tire circumferential direction is reduced, and the tire circumferential direction of the tread portion 2 is reduced. There is a possibility that the rigidity cannot be sufficiently increased.

  On the other hand, when the length L4 exceeds 10% of the tread width TW, the rigidity in the tire circumferential direction may become excessive due to the action of the second crown block 21 and the second shoulder block 22 adjacent to each other in the tire circumferential direction supporting each other. There is. As a result, the deformation of the second crown block 21 and the second shoulder block 22 during straight travel is suppressed, which may affect the heat generation of the tread rubber.

  It is desirable that the first protrusions 12P and the second protrusions 22P are alternately provided in the tire circumferential direction. By such first projecting portion 12P and second projecting portion 22P, the rigidity of the tread portion 2 is made uniform, the heat generation of the tread portion 2 is made uniform, and the steering stability performance of the racing cart tire 1 is improved. .

  As shown in FIG. 1, the tread portion 2 includes a first tread half 2A that is an area from the tire equator C to the first tread end Te1, and a tread end opposite to the first tread end Te1 from the tire equator C. And a second tread half portion 2B which is a region up to the second tread end Te2.

  In the tread portion 2, a plurality of first inclined grooves 5 and a plurality of second inclined grooves 6 are provided alternately in the tire circumferential direction. The first inclined groove 5 and the second inclined groove 6 are formed to be inclined in opposite directions.

  The first inclined groove 5 has an inner end 5i provided in the second tread half 2B and an outer end 5o provided in the first tread half 2A. The inner end 5i of the first inclined groove 5 communicates with the second inclined groove 6 at the second tread half 2B. The outer end 5o of the first inclined groove 5 opens to the first tread end Te1. The width W1 of the first inclined groove 5 is, for example, preferably 5 mm or more, more preferably 6 mm or more, and preferably 8 mm or less, more preferably 9 mm or less. The depth of the first inclined groove 5 is, for example, preferably 4 mm or more, more preferably 5 mm or more, and preferably 7 mm or less, more preferably 6 mm or less.

  The first inclined groove 5 includes a first crown lateral groove 51 that is a first portion, a first crown inclined groove 52 that is a second portion, and a first shoulder inclined groove 53 that is a third portion.

  On the other hand, the second inclined groove 6 has an inner end 6i provided in the first tread half 2A and an outer end 6o provided in the second tread half 2B. The inner end 6i of the second inclined groove 6 communicates with the first inclined groove 5 at the first tread half 2A. The outer end 6o of the second inclined groove 6 opens to the second tread end Te2. The width W2 of the second inclined groove 6 is, for example, preferably 5 mm or more, more preferably 6 mm or more, and preferably 8 mm or less, more preferably 9 mm or less. The depth of the second inclined groove 6 is, for example, preferably 4 mm or more, more preferably 5 mm or more, and preferably 7 mm or less, more preferably 6 mm or less.

  The second inclined groove 6 includes a second crown lateral groove 61 that is a first portion, a second crown inclined groove 62 that is a second portion, and a second shoulder inclined groove 63 that is a third portion.

  The first crown lateral grooves 51 and the second crown lateral grooves 61 are alternately provided on the tire equator C. Each first crown lateral groove 51 and each second crown lateral groove 61 are provided between the first crown block 11 and the second crown block 21 arranged in the tire circumferential direction. The drainage performance in the vicinity of the tire equator C is enhanced by the first crown lateral groove 51 and the second crown lateral groove 61, and the wet performance is improved.

  The first crown inclined groove 52 and the first shoulder inclined groove 53 are provided on the first shoulder block 12 side of the tread portion 2.

  The first crown inclined groove 52 extends between the first crown block 11 and the second crown block 21 and the first shoulder block 12 while being inclined with respect to the tire circumferential direction. The first crown inclined groove 52 communicates with the first crown lateral groove 51 and the second crown lateral groove 61. The first crown inclined groove 52 enhances the drainage performance between the first crown block 11 and the second crown block 21 and the first shoulder block 12 and improves the wet performance.

  The first shoulder inclined groove 53 extends between the first shoulder blocks 12 arranged in the tire circumferential direction so as to be inclined with respect to the tire axial direction. One end of the first shoulder inclined groove 53 is continuous with the first crown inclined groove 52 and reaches the first tread end Te1. The first shoulder inclined groove 53 enhances the drainage performance in the shoulder region on the first tread end Te1 side and improves the wet performance.

  On the other hand, the second crown inclined groove 62 and the second shoulder inclined groove 63 are provided on the second shoulder block 22 side of the tread portion 2.

  The second crown inclined groove 62 extends between the first crown block 11 and the second crown block 21 and the second shoulder block 22 while being inclined with respect to the tire circumferential direction. The second crown inclined groove 62 communicates with the first crown lateral groove 51 and the second crown lateral groove 61. The second crown inclined groove 62 enhances the drainage performance between the first crown block 11 and the second crown block 21 and the second shoulder block 22 and improves the wet performance.

  The second shoulder inclined groove 63 extends between the second shoulder blocks 22 arranged in the tire circumferential direction so as to be inclined with respect to the tire axial direction. One end of the second shoulder inclined groove 63 is connected to the second crown inclined groove 62 and reaches the second tread end Te2. By the second shoulder inclined groove 63, the drainage performance in the shoulder region on the second tread end Te2 side is enhanced, and the wet performance is improved.

  The land ratio of the shoulder area A2, which is a quarter of the tread width TW from the first tread end Te1 and the second tread end Te2, is a crown which is a half of the tread width TW centered on the tire equator C. It is desirable that it is larger than the land ratio of the area A1. By setting the land ratio of the shoulder region A2 and the crown region A1 as described above, the rigidity of the tread portion 2 in the crown region A1 is relatively lower than the rigidity of the tread portion 2 in the shoulder region A2, and the crown The warming performance of the tread rubber in the region A1 is improved. Further, the rigidity of the tread portion 2 in the shoulder region A2 is relatively higher than the rigidity of the tread portion 2 in the crown region A1, and the grip performance and steering stability performance during cornering are improved.

  The first shoulder block 12 is divided into two in the tire circumferential direction by the third narrow groove 13. The third narrow groove 13 connects the first crown inclined groove 52 and the first tread end Te1, and extends in a zigzag shape in the tire axial direction. By providing the third narrow groove 13 in the first shoulder block 12, the drainage performance of the first crown inclined groove 52 and the first shoulder inclined groove 53 is assisted, and in the vicinity of the first tread end Te1 during cornering. The drainage performance is further improved.

  Similarly, the second shoulder block 22 is divided into two in the tire circumferential direction by the fourth narrow groove 24. The fourth narrow groove 24 connects the second crown inclined groove 62 and the second tread end Te2 and extends in a zigzag shape in the tire axial direction. By providing the fourth narrow groove 24 in the second shoulder block 22, the drainage performance of the second crown inclined groove 62 and the second shoulder inclined groove 63 is assisted, and in the vicinity of the second tread end Te2 during cornering. The drainage performance is further improved.

  As mentioned above, although the tire for racing carts of this invention was demonstrated in detail, this invention is changed and implemented in various aspects, without being limited to said specific embodiment.

  A racing cart tire (front wheel size 10 × 4.50-5, rear wheel size 11 × 6.50-5) having the tread pattern of FIG. 1 was prototyped based on the specifications in Table 1 and warming performance on a wet road surface And the steering stability performance was tested. The test method is as follows.

<Warming performance>
Each sample tire mounted on the rim (front wheel 5 × 4.5, rear wheel 5 × 6.5) was mounted on a racing cart of a two-cycle engine with a displacement of 100 cc under the condition of an internal pressure of 100 kPa. The test track on the wet asphalt road was run twice with one driver on board, and the temperature of the tread immediately after was measured. A result is an index | exponent which makes Example 1 100, and shows that warming performance is excellent, so that a numerical value is large.

<Steering stability>
The vehicle traveled seven laps on the test course, and characteristics relating to steering response, responsiveness, and grip were evaluated by the driver's sensuality. A result is a grade which sets Example 1 to 100, and shows that steering stability performance is excellent, so that a numerical value is large.

  As is clear from Table 1, it was confirmed that the racing cart tires of the examples had significantly improved warming performance and steering stability performance as compared with the comparative examples.

2 Tread 3 Crown block 4 Shoulder block

Claims (9)

A racing cart tire with a tread,
The tread portion is
On the tire equator, a plurality of crown blocks arranged in the tire circumferential direction,
A plurality of shoulder blocks arranged in the tire circumferential direction on both outer sides of the crown block,
Each crown block has a horizontally long shape with a maximum length in the tire axial direction larger than a maximum length in the tire circumferential direction,
In addition, the maximum length of the crown block in the tire axial direction is 30 to 60% of the tread width.   The racing cart tire according to claim 1, wherein a tread surface of the crown block has a trapezoidal shape.   The racing cart tire according to claim 2, wherein the tread surface of the crown block includes an upper base having an angle of 80 ° to 100 ° with respect to a tire circumferential direction.   The racing cart tire according to claim 2 or 3, wherein the tread surface of the crown block includes a lower bottom having an angle of 80 ° to 100 ° with respect to a tire circumferential direction.   The racing cart tire according to claim 4, wherein an inner portion of the shoulder block in the tire axial direction includes a protrusion that contacts the lower bottom of the crown block or faces through a narrow groove having a width of 2 mm or less. .   The tire for a racing cart according to claim 5, wherein a length of the protruding portion in the tire axial direction is 2 to 10% of a tread width. The shoulder block includes a plurality of first shoulder blocks disposed on the right side of the crown block and a plurality of second shoulder blocks disposed on the left side of the crown block;
The protrusion includes a first protrusion provided on the first shoulder block and a second protrusion provided on the second shoulder block,
The racing cart tire according to claim 5 or 6, wherein the first protrusions and the second protrusions are alternately provided in a tire circumferential direction. In the tread part,
A crown inclined groove extending between the crown block and the shoulder block;
The tire for a racing cart according to any one of claims 1 to 7, further comprising a shoulder inclined groove that has one end connected to the crown inclined groove and extends between shoulder blocks arranged in the tire circumferential direction to reach the tread end.   The land ratio of the shoulder region that is a quarter of the tread width from the tread end is larger than the land ratio of the crown region that is a half of the tread width around the tire equator. A racing cart tire according to any one of the above.

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