Pneumatic tires

Abstract

To provide a tire that suppresses a rim deviation during severe traveling while suppressing the damage to a bead tow when assembling a rim.SOLUTION: A pneumatic tire is equipped with a tread portion, a pair of side wall portions, a pair of bead portions 4 respectively embedded with bead cores 5, a toroidal carcass 6 arranged between the pair of bead portions 4, and a side wall rubber 3G that is arranged on the outer side in a tire axial direction of the carcass in each of the pair of side wall portions. Each of the pair of bead portions 4 is equipped with a bead bottom surface 40 in contact with a bead seat surface Rs of a rim R. The bead bottom surface 40 includes an inner area 41 in the tire axial direction including a bead tow Bt, and an outer area 42 in the tire axial direction including a bead heel Bh. The inner area 41 is formed by a canvas chafer 45. The outer area 42 is formed by the side wall rubber 3G extending inward in a tire radial direction from the side wall portion.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] When a pneumatic tire is used under high load or high severity conditions, such as during a race, the tire may slip against the rim (rim misalignment).

[0003] In order to suppress such rim slippage, it has been proposed to place a rubber chafer or clinch rubber having a specific composition on the bottom surface of the bead of the pneumatic tire (for example, see Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-199465 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0005] When a pneumatic tire is mounted on a rim, the bead toe, which is the inner end of the bead bottom in the tire axial direction, rubs against the rim and is subjected to a large force. This tendency is particularly noticeable in pneumatic tires for racing vehicles, which have high side rigidity. In pneumatic tires in which the bead bottom is made of clinch rubber or the like, there is a problem that the bead toe is easily chipped during assembly with the rim, which in turn impairs the air seal.

[0006] The present invention was devised in consideration of the above-mentioned problems, and its main object is to provide a pneumatic tire that can suppress damage to the bead toe when assembled to the rim while suppressing rim slippage during severe driving. [Means for solving the problem]

[0007] The present invention is a pneumatic tire comprising a tread portion, a pair of sidewall portions, a pair of bead portions each having a bead core embedded therein, a toroidal carcass disposed between the pair of bead portions, and a sidewall rubber disposed axially outward of the carcass in each of the pair of sidewall portions, each of the pair of bead portions having a bead bottom surface that contacts a bead seat surface of a rim, the bead bottom surface including an axially inner region including a bead toe and an axially outer region including a bead heel, the inner region being formed by a canvas chafer, and the outer region being formed by the sidewall rubber extending radially inward from the sidewall portions.

[0008] In another aspect of the present invention, the axial length of the inner region may be 2 mm or more.

[0009] In another aspect of the present invention, the axial length of the inner region may be Lc+0.5Wb or less, where Lc is the axial length from the bead toe to the center of the bead core, and Wb is the axial width of the bead core.

[0010] In another aspect of the invention, the canvas chafer may include a first portion extending in the inner region in the tire axial direction, and a second portion extending from the bead toe outward in the tire radial direction.

[0011] In another aspect of the invention, the canvas chafer may include a third portion in the outer region that is overlapped on the outer side of the sidewall rubber in the tire radial direction.

[0012] In another aspect of the invention, the canvas chafer may include a fourth portion that is connected to the third portion and extends radially outward in the tire radial direction.

[0013] In another embodiment of the present invention, the sidewall rubber may have a complex modulus of elasticity of 2 to 10 MPa.

[0014] In another embodiment of the present invention, the sidewall rubber may have a thickness of 0.5 to 2.0 mm in the outer region.

[0015] In another aspect of the present invention, each of the pair of bead portions is provided with a clinch rubber having a complex modulus greater than that of the sidewall rubber, and the clinch rubber may include a first clinch rubber provided between the sidewall rubber and the carcass.

[0016] In another aspect of the present invention, each of the pair of bead portions is provided with a clinch rubber having a complex modulus greater than that of the sidewall rubber, and the clinch rubber may include a second clinch rubber superimposed on the radially outer side of the canvas chafer in the inner region.

[0017] In another embodiment of the present invention, the ratio (E*s / E*c) of the complex modulus E*s of the sidewall rubber to the complex modulus E*c of the clinch rubber may be 0.10 to 0.20.

[0018] In another aspect of the present invention, the compression may be 10% to 16% at an inner portion of the bead core in the tire radial direction. Effect of the Invention

[0019] By employing the above-described configuration, the pneumatic tire of the present invention can suppress damage to the bead toe when assembled to the rim, while suppressing rim slippage during severe driving. [Brief description of the drawings]

[0020] [Figure 1] 1 is a right half cross-sectional view of a pneumatic tire showing one embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of a main part of a bead portion in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a cross-sectional view of a pneumatic tire (hereinafter, sometimes simply referred to as "tire") 1 according to this embodiment. In Fig. 1, the tire 1 is in a normal state.

[0022] [Definition] In this specification, the "normal state" of the tire 1 means a state in which the tire 1 is mounted on a normal rim R, the internal pressure is adjusted to a normal internal pressure, and no load is applied to the tire 1. Unless otherwise specified, in this specification, the dimensions of each part of the tire 1 refer to values ​​measured in this normal state.

[0023] In this specification, a "genuine rim" is a rim that is defined for each tire by a standard system that includes the standard on which tire 1 is based, such as a "standard rim" in the case of JATMA, a "Design Rim" in the case of TRA, or a "Measuring Rim" in the case of ETRTO.

[0024] In this specification, the "normal internal pressure" refers to the air pressure determined for each tire by each standard in a standard system including the standard on which tire 1 is based, and is, for example, the "maximum air pressure" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and the "INFLATION PRESSURE" in the case of ETRTO.

[0025] As shown in Fig. 1, the tire 1 includes a tread portion 2, a pair of sidewall portions 3, a pair of bead portions 4 each having a bead core 5 embedded therein, and an air-impermeable inner liner rubber 10 disposed on the tire cavity surface. Note that Fig. 1 shows only the right half of the tire 1, but the left half has a similar structure to the right half.

[0026] The tire 1 of this embodiment is shown as a tire for a racing vehicle used under high load and high severity conditions. A tire for a racing vehicle is a pneumatic tire intended for circuit driving. There are cases where there are no tire standards for tires for racing vehicles. In such cases, the rim and internal pressure that will most appropriately exhibit the running performance of the tire are determined as the regular rim and regular internal pressure, respectively. At that time, the recommended values ​​by the tire manufacturer, etc., the race regulations, etc. may be taken into consideration.

[0027] In other aspects of the invention, the tire 1 may be embodied as a pneumatic tire, for example, for passenger cars or light trucks.

[0028] The tire 1 also includes a toroidal carcass 6 disposed between the pair of bead portions 4, 4, and a belt layer 7 disposed outside the carcass 6 in the tire radial direction.

[0029] In this embodiment, the carcass 6 includes, for example, one or more carcass plies 6A in which a plurality of carcass cords are covered with a topping rubber. The carcass cords are oriented at an angle of, for example, 80 to 90 degrees with respect to the tire equator C. As the carcass cords, for example, organic fiber cords are suitably used.

[0030] The carcass ply 6A includes, for example, a main body portion 6a extending between the pair of bead cores 5, and a pair of turn-up portions 6b that are turned up from the inside to the outside in the tire axial direction around the pair of bead cores 5. In a preferred embodiment, each bead portion 4 has a bead apex 8 made of hard rubber that extends in a tapered shape from the bead core 5 to the outside in the tire radial direction between the main body portion 6a and the turn-up portions 6b.

[0031] The belt layer 7 is composed of a plurality of (two in this embodiment) belt plies 7A, 7B. Each of the belt plies 7A, 7B includes a steel cord oriented at an angle of, for example, 15 to 40 degrees with respect to the tire equator C. Such a belt layer 7 hoops the carcass 6 and increases the rigidity of the tread portion 2.

[0032] The tire 1 of this embodiment further includes a band layer 9 disposed on the outer side of the belt layer 7 in the tire radial direction. The band layer 9 includes one or more band plies. Each band ply includes a band cord oriented at an angle of 5° or less with respect to the tire circumferential direction. As the band cord, for example, an organic fiber cord is preferably used.

[0033] The band ply of this embodiment has a so-called jointless structure in which a band cord is wound spirally in the tire circumferential direction. The band layer 9 of this embodiment includes a full band ply 9A that covers the belt layer 7 over almost the entire width thereof, and an edge band ply 9B that covers only the outer end portion of the belt layer 7 in the tire axial direction. The band layer 9 as described above suppresses the rising of the tread portion 2 during high-speed running, and improves the steering stability and durability during high-speed running.

[0034] In this embodiment, a tread rubber 2G is disposed in the tread portion 2 on the outer side in the tire radial direction of the band layer 9. The tread rubber 2G is disposed at least in a portion that comes into contact with the road surface.

[0035] In each of the pair of sidewall portions 3, a sidewall rubber 3G is disposed on the axially outer side of the carcass 6. The sidewall rubber 3G is formed of a relatively soft rubber material in order to maintain the flexibility of the sidewall portion 3 during running.

[0036] The sidewall rubber 3G extends in the radial direction of the tire along the carcass 6. An outer end of the sidewall rubber 3G in the radial direction of the tire is connected to the tread rubber 2G. An inner end of the sidewall rubber 3G in the radial direction of the tire extends to a bead portion 4. This will be described later.

[0037] FIG. 2 shows a partial enlarged view of the bead portion 4 in FIG. As shown in Fig. 2, each of the pair of bead portions 4 has a bead bottom surface 40. The bead bottom surface 40 is a portion that contacts a bead seat surface Rs of a regular rim (hereinafter sometimes simply referred to as "rim") R. In this specification, the bead seat surface Rs of the rim R means a portion that supports the bead portion 4 from the inside in the tire radial direction, on the inner side in the rim width direction than the position of the rim diameter Dr, as shown in Fig. 2.

[0038] The bead bottom surface 40 includes an axially inner region 41 including a bead toe Bt, and an axially outer region 42 including a bead heel Bh.

[0039] In this specification, the bead toe Bt means the axially innermost end of the bead bottom surface 40. In addition, for the sake of convenience, the bead heel Bh means the position of the bead bottom surface 40 corresponding to the rim diameter Dr.

[0040] In the tire 1 of this embodiment, the inner region 41 of the bead bottom surface 40 is formed by a canvas chafer 45. The outer region 42 is formed by a sidewall rubber 3G extending radially inward from the sidewall portion 3. An interface F is formed at the bead bottom surface 40 where the canvas chafer 45 and the sidewall rubber 3G are connected.

[0041] The canvas chafer 45 is a cloth-rubber composite in which cloth is covered with rubber, and has superior resistance to external damage compared to a so-called rubber chafer made of rubber alone. In this embodiment, the inner region 41 of the bead bottom surface 40 is formed of the canvas chafer 45, thereby suppressing damage to the bead toe Bt during rim assembly, etc. Therefore, the tire 1 of this embodiment suppresses a decrease in air sealing performance caused by damage to the bead toe Bt.

[0042] On the other hand, the canvas chafer 45 tends to have a lower contact area with the bead seat surface Rs of the rim R compared to the rubber chafer because the amount of deformation is small and a part of the cloth is exposed. This is not preferable from the viewpoint of preventing rim slippage. Therefore, in the tire 1 of the present embodiment, the soft sidewall rubber 3G is arranged in the outer region 42 of the bead bottom surface 40. In this embodiment, in the outer region 42 of the bead bottom surface 40, the sidewall rubber 3G is in close contact with the bead seat surface Rs of the rim R due to its own compressive deformation, and thus the contact area with the bead seat surface Rs increases. Since the friction coefficient of rubber is pressure dependent, the sidewall rubber 3G as described above can generate a high friction force between the bead bottom surface 40 and the bead seat surface Rs by increasing the contact area and uniforming the pressure distribution.

[0043] As described above, the bead bottom surface 40 of the tire 1 of this embodiment has a canvas chafer 45 with excellent resistance to external damage arranged in its inner region 41, and a sidewall rubber 3G that generates high friction between itself and the bead seat surface Rs arranged in its outer region 42, thereby suppressing damage to the bead toe Bt when assembled to the rim while suppressing rim slippage during severe driving conditions.

[0044] In addition, in the tire 1 of the present embodiment, there is no need to use a new rubber member to solve the above problem, since the sidewall rubber 3G is extended and disposed in the outer region 42. Therefore, the tire 1 of the present embodiment can be manufactured, for example, without increasing the manufacturing process or the number of parts.

[0045] In order to more effectively exert the above-mentioned effect of suppressing damage to the bead toe Bt when assembled to the rim while suppressing rim slippage during severe driving, the axial length Li of the inner region 41 is preferably set to 2 mm or more, and more preferably set to 3 mm or more.

[0046] On the other hand, if the axial length Li of the inner region 41 is large, the axial length Lo of the outer region 42 at the bead bottom surface 40 will be small, which may reduce the effect of suppressing rim slippage during severe driving. From this perspective, it is preferable that the axial length Li of the inner region 41 is equal to or less than Lc+0.5Wb, more preferably less than Lc+0.5Wb, where Lc is the axial length from the bead toe Bt to the center 5c of the bead core 5, and Wb is the axial width of the bead core 5.

[0047] In a preferred embodiment, it is desirable that at least a part of the sidewall rubber 3G is present in the inner region in the tire radial direction of the bead core 5 (the inner region of the width Wb of the bead core 5) where the contact pressure with the bead seat surface Rs of the rim R is high. In other words, it is desirable that the interface F is located in the inner region of the bead core 5 in the tire radial direction.

[0048] In a particularly preferred embodiment, as in the present embodiment, it is desirable to have the sidewall rubber 3G located at the inner position in the tire radial direction of the center 5c of the bead core 5 where the contact pressure with the bead seat surface Rs of the rim R is the highest. This further improves the rim slippage suppression effect.

[0049] [Embodiment of canvas chafer] The canvas chafer 45 of this embodiment includes, for example, a first portion 45a extending in the tire axial direction in the inner region 41, and a second portion 45b extending from the bead toe Bt to the tire radial direction outside. Such a canvas chafer 45 can reinforce the bead toe Bt in both the tire axial direction and the tire radial direction, and damage to the bead toe Bt during rim assembly is more reliably suppressed.

[0050] The canvas chafer 45 of this embodiment may further include a third portion 45c superimposed on the outer side of the sidewall rubber in the tire radial direction in the outer region 42. The third portion 45c is continuous with the first portion 45a. The third portion 45c of the canvas chafer 45 effectively transmits the tightening force of the bead core 5 to the sidewall rubber 3G located on the inner side in the tire radial direction, and thus helps to further increase the friction force of the outer region 42 against the bead seat surface Rs.

[0051] The canvas chafer 45 of this embodiment may further include a fourth portion 45d that is connected to the third portion 45c and extends radially outward of the tire. The fourth portion 45d of this embodiment extends radially between the sidewall rubber 3G and the carcass 6. Such a fourth portion 45d not only helps to increase the bending rigidity of the bead portion 4, but also brings the sidewall rubber 3G into close contact with the rim flange, which can further suppress rim slippage.

[0052] [Sidewall rubber] The complex elastic modulus of the sidewall rubber 3G is preferably 10 MPa or less, more preferably 8 MPa or less, and further preferably 6 MPa or less. When the sidewall rubber 3G is attached to the rim, it is possible for it to be sufficiently compressed and deformed between the sidewall rubber 3G and the bead seat surface Rs of the bead bottom surface 40, and thus it is possible to generate a high frictional force between the sidewall rubber 3G and the bead seat surface Rs, and to more effectively suppress the rim slippage.

[0053] On the other hand, if the complex modulus of the sidewall rubber 3G is excessively small, the amount of deformation of the outer region 42 during running of the tire may become large, which may result in deterioration of steering stability. From this viewpoint, the complex modulus of the sidewall rubber 3G is preferably 2 MPa or more, more preferably 3 MPa or more, and further preferably 4 MPa or more.

[0054] In this specification, the complex modulus of rubber is measured by taking a rubber sample for viscoelasticity measurement, 20 mm long x 4 mm wide x 1 mm thick, from a target site, and measuring it using an Iplexer series made by GABO under the following conditions: temperature 100°C, initial strain 5%, dynamic strain 1%, frequency 10 Hz, and elongation mode. In the case of sidewall rubber 3G, the rubber sample is taken so that the long side is in the tire circumferential direction.

[0055] In the outer region 42 of the bead bottom surface 40, the thickness of the sidewall rubber 3G is preferably in the range of 0.5 to 2.0 mm. By making the thickness of the sidewall rubber 3G 0.5 mm or more, a sufficient compression deformation region of the sidewall rubber 3G can be obtained in the tire radial direction, and a high friction force can be generated between the sidewall rubber 3G and the bead seat surface Rs. In addition, by making the thickness of the sidewall rubber 3G 2.0 mm or less, the amount of excessive rubber deformation in the outer region 42 is suppressed, and deterioration of steering stability is prevented. Note that the thickness of the sidewall rubber 3G is the thickness in the direction perpendicular to the bead bottom surface 40.

[0056] [Clinch rubber] In a preferred embodiment, each of the pair of bead portions 4 may be provided with a clinch rubber 4G having a complex elastic modulus greater than that of the sidewall rubber 3G.

[0057] In this embodiment, the clinch rubber 4G can include a first clinch rubber 4G1 disposed between the sidewall rubber 3G and the carcass 6 in the bead portion 4. The first clinch rubber 4G1 is disposed from the sidewall portion 3 to the bead portion 4, thereby increasing the bending rigidity of the tire side portion. Therefore, the tire 1 of this embodiment can exhibit excellent steering stability as a tire for a racing vehicle.

[0058] In this embodiment, the clinch rubber 4G may include a second clinch rubber 4G2 overlapped on the outer side of the canvas chafer 45 in the tire radial direction in the inner region 41. The second clinch rubber 4G2 in this embodiment is disposed adjacent to the first portion 45a and the second portion 45b of the canvas chafer 45. Such a second clinch rubber 4G2 further effectively reinforces the bead toe Bt side of the bead portion 4, so that damage to the bead toe Bt is further suppressed.

[0059] The complex modulus of the clinch rubber 4G is not particularly limited as long as it is greater than the complex modulus of the sidewall rubber 3G. In a preferred embodiment, in order to exert the effect of preventing rim slippage without impairing the steering stability of the tire 1 during high-speed driving, it is effective to correlate the rigidity of the inner region 41 with the rigidity of the outer region 42 and provide a certain rigidity difference between them. More specifically, the ratio (E*s / E*c) between the complex modulus E*s of the sidewall rubber 3G and the complex modulus E*c of the clinch rubber 4G is preferably set to 0.20 or less. On the other hand, if the ratio between the complex modulus E*s of the sidewall rubber 3G and the complex modulus E*c of the clinch rubber 4G becomes excessively small, it may be difficult to achieve both steering stability during high-speed driving and the effect of preventing rim slippage. From this viewpoint, the ratio (E*s / E*c) is preferably set to 0.10 or more.

[0060] [Compression] In a preferred embodiment, the compression is desirably 10% to 16% at the radially inner portion of the bead core 5. In this specification, the compression is a value obtained by dividing the thickness of the under-core portion 46 located on the radially inner side of the bead core 5 by the thickness before assembly on the rim. For convenience, in this specification, the compression is specified on a radial line CL passing through the center 5c of the bead core 5.

[0061] The static friction coefficient of rubber is pressure dependent as described above. Therefore, the friction force can be maximized by optimizing the pressure of the core under portion 46. As a result of various experiments, assuming the bead structure of the tire 1 of the present invention, when the compression of the core under portion 46 during assembly with the rim is 10% to 16%, the friction force between the bead seat surface Rs is maximized, and thus a higher rim slippage suppression effect can be obtained.

[0062] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above specific disclosure, and can be implemented in various modified forms within the scope of the technical ideas described in the claims. EXAMPLES

[0063] More specific, non-limiting examples of the present invention will now be described. A prototype pneumatic tire for racing vehicles having the basic structure shown in Figures 1 and 2 was manufactured and the following tests were carried out. For comparison, the same tests were also carried out on Comparative Example 1, in which the entire area of ​​the bead bottom surface was formed with a canvas chafer, and Comparative Example 2, in which the entire area of ​​the bead bottom surface was formed with a rubber chafer.

[0064] [Bead toe damage resistance] The prototype tire was mounted on the rim, then removed again, three times, and the presence or absence of damage to the bead part, including the bead toe, was confirmed. In Table 1, the results are scored based on a score of 100 for no damage, and for any damage, the score was deducted from 100 according to the degree of damage.

[0065] [Handling stability] The prototype tire was mounted on a rim (size: 18 x 13.0J) without applying any anti-slip agent, and the tire was filled with air to adjust the internal pressure to 180 kPa. This tire-rim assembly was mounted on all wheels of a racing vehicle (FIA-GT3 vehicle). A professional driver then drove the vehicle at full speed on a racing circuit, and the handling stability was evaluated by the driver's senses. In Table 1, the results are shown as a score, with a higher score indicating better performance.

[0066] [Rim slippage resistance] After the driving stability test run, the amount of deviation between the tire and the rim in the tire circumferential direction was measured. The measurement was performed by marking the rim and the tire in advance, and measuring the amount of deviation between the markings after the run. In Table 1, the results are shown as indexes, with the larger the number, the better the result. The results of the tests are shown in Table 1.

[0067] [Table 1]

[0068] As is clear from Table 1, compared to the tires of Comparative Examples 1 and 2, it was confirmed that the tires of the examples can suppress damage to the bead toe when assembled to the rim, while also suppressing rim slippage during severe driving.

[0069] Next, similar tests were carried out on the tires of the present invention by changing the specifications of the tires (Examples 1 to 8). The test results are shown in Table 2.

[0070] [Table 2]

[0071] As is clear from Table 2, it can be confirmed that the tires of Examples 1 to 8 exhibit good performance.

[0072] Further, similar tests were carried out on the tires of the present invention by changing the compression (Examples 9 to 11). The test results are shown in Table 3.

[0073] [Table 3]

[0074] As is clear from Table 3, it can be confirmed that the tires of Examples 9 to 11 exhibit good performance. [Explanation of symbols]

[0075] 1 Tire 2 Tread section 3 Sidewall 3G Sidewall Rubber 4 Bead section 4G Clinch Rubber 4G1 First clinch rubber 4G2 2nd clinch rubber 5 Bead Core 40 Bead bottom 41 Inner area 42 Outer area 45 Canvas Chafer 45a Part 1 45b Part 2 45c Part 3 45d Part 4 Bt Bead Toe Bh Bead Heel R Rim Rs Bead seat surface

Claims

1. A pneumatic tire, A tread portion; A pair of sidewall portions; A pair of bead portions each having a bead core embedded therein; a toroidal carcass disposed between the pair of bead portions; a sidewall rubber disposed on an axially outer side of the carcass in each of the pair of sidewall portions, Each of the pair of bead portions has a bead bottom surface that contacts a bead seat surface of a rim, the bead bottom surface includes an axially inner region including a bead toe and an axially outer region including a bead heel, The inner region is formed by a canvas chafer; The outer region is formed by the sidewall rubber extending from the sidewall portion toward the inside in the tire radial direction, A clinch rubber having a complex elastic modulus greater than that of the sidewall rubber is disposed in each of the pair of bead portions, The clinch rubber includes a first clinch rubber disposed between the sidewall rubber and the carcass. Pneumatic tires.

2. The pneumatic tire according to claim 1 , wherein the inner region has an axial length of 2 mm or more.

3. 3. The pneumatic tire according to claim 1, wherein the axial length of the inner region is equal to or less than Lc+0.5Wb, where Lc is the axial length from the bead toe to the center of the bead core, and Wb is the axial width of the bead core.

4. 4. The pneumatic tire according to claim 1, wherein the canvas chafer includes a first portion extending in the inner region in the tire axial direction, and a second portion extending from the bead toe outward in the tire radial direction.

5. 5. The pneumatic tire according to claim 1, wherein the canvas chafer includes a third portion overlapping the sidewall rubber on an outer side in the tire radial direction in the outer region.

6. The pneumatic tire according to claim 5 , wherein the canvas chafer includes a fourth portion that is connected to the third portion and extends radially outward in the tire radial direction.

7. 7. The pneumatic tire according to claim 1, wherein the sidewall rubber has a complex modulus of elasticity of 2 to 10 MPa.

8. 8. The pneumatic tire according to claim 1, wherein the sidewall rubber has a thickness of 0.5 to 2.0 mm in the outer region.

9. A pneumatic tire as described in any one of claims 1 to 8, wherein the clinch rubber includes a second clinch rubber superimposed on the radially outer side of the canvas chafer in the inner region.

10. A pneumatic tire described in any one of claims 1 to 9, wherein the ratio (E*s / E*c) of the complex modulus E*s of the sidewall rubber to the complex modulus E*c of the clinch rubber is 0.10 to 0.20 or less.

11. A pneumatic tire as described in any one of claims 1 to 10, wherein the compression at the radially inner portion of the bead core is 10% to 16%.

Images