JP5385662B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire including a pair of bead portions and a carcass layer including a carcass cord locked to the bead portions.

  Conventionally, in research and development of pneumatic tires, various methods have been sought for improving performance that is inherently in a trade-off relationship, for example, both steering stability and ride comfort.

  For example, a tread pattern centered on the tire equator plane and located outside when mounted on a vehicle (hereinafter abbreviated as outside when mounted on the vehicle) and positioned inside when mounted on the vehicle (hereinafter referred to as when mounted on the vehicle) A method using a so-called asymmetric tread pattern that makes the tread pattern different is widely known (for example, Patent Document 1).

  Specifically, in order to make the tread rigidity on the outer side when the vehicle is mounted higher than the inner side when the vehicle is mounted, a tread pattern in which ribs extending along the tire circumferential direction are formed on the outer side when the vehicle is mounted is used. According to the pneumatic tire in which such an asymmetric tread pattern is formed, the outer tread rigidity when the vehicle is mounted, which greatly contributes to the motion performance of the vehicle at the time of steering, is increased, so the response at the start of steering and the cornering performance In particular, cornering performance is improved when the steering angle increases. Further, the tread rigidity on the inner side when the vehicle is mounted is lower than that on the outer side when the vehicle is mounted, so that the riding comfort is also improved.

JP-A-1-266001 (FIGS. 3 and 5)

  By the way, in the case of a passenger car traveling on a general road, the cornering opportunities that require a large steering angle at a certain speed or higher are extremely limited. That is, in a pneumatic tire mounted on such a passenger car, improvement in steering stability in a so-called limit region is not always strongly demanded.

  On the other hand, in such a passenger car, it is desirable to improve the steering stability required in normal driving, such as that the driver can easily maintain driving in the lane. That is, it is desirable to improve steering stability in a region where the steering angle is small (for example, a slip angle of about 1 degree or less).

  Therefore, the present invention has been made in view of such a situation, and an object thereof is to provide a pneumatic tire that further improves the steering stability in a region where the steering angle is small without reducing the riding comfort. And

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is an air comprising a pair of bead portions (bead portion 14) and a carcass layer (carcass layer 12) including a carcass cord (carcass cord 11) locked to the bead portion. A rim wheel that is an entered tire (pneumatic tire 1) and protrudes from the inside sidewall portion to the inside sidewall portion (inside sidewall portion 21) that is located on the inside when the vehicle is mounted, and on which the pneumatic tire is assembled An inner rim guard (inner rim guard 31) for protecting the rim wheel is formed, and an outer side wall portion (outer side wall portion 22) located outside when the vehicle is mounted projects from the outer side wall portion to protect the rim wheel. A rim guard (outer rim guard 32) is formed, and the inner rim guard along the tread width direction (W direction) is formed. Cross-sectional area of de (cross-sectional area S1) is summarized as larger than the cross-sectional area of the outer rim guard along the tread width direction (cross-sectional area S2).

  According to the first feature of the present invention, the cross-sectional area of the inner rim guard is larger than the cross-sectional area of the outer rim guard. That is, the rigidity of the inner sidewall portion where the inner rim guard is formed is higher than the rigidity of the outer sidewall portion where the outer rim guard is formed. Therefore, the cornering force rises quickly during steering. Thereby, even if a steering angle is small, steering stability (responsiveness) improves.

  The second feature of the present invention relates to the first feature of the present invention, and is the inner portion (inner portion Cin) in which the carcass cord is located on the innermost side of the vehicle when attached to the vehicle, and the attachment to the vehicle. In some cases, the carcass cord has an outer portion (outer portion Cout) located on the outermost side of the vehicle, and an outer height (outer height SWHout) that is the height of the outer portion with respect to the position of the bead portion. ) Is higher than the inner height (inner height SWHin) which is the height of the inner portion with respect to the position of the bead portion.

  According to the second feature of the present invention, when the vehicle is mounted, the height of the inner portion based on the position of the bead portion is lower than the height of the outer portion based on the position of the bead portion. Therefore, the radius of curvature of the curved portion from the tread portion of the pneumatic tire to the inner sidewall portion is increased. Thereby, the rigidity with respect to the bending deformation from the tread portion to the inner sidewall portion increases. Therefore, the cornering force rises quickly during steering. Thereby, steering stability (responsiveness) in a region where the steering angle is small is improved.

  A third feature of the present invention relates to the first feature of the present invention, wherein an inner rubber amount of the inner sidewall portion including the inner rim guard, and an outer rubber amount of the outer sidewall portion including the outer rim guard, Are the same.

  A fourth feature of the present invention relates to the second feature of the present invention, wherein a distance (distance d1) from the inner sidewall portion to the protruding end (protruding end 31a) of the inner rim guard, and from the outer sidewall portion to the above-mentioned The gist is that the distance (distance d2) to the protruding end (protruding end 32a) of the outer rim guard is substantially the same.

  A fifth feature of the present invention relates to the first feature of the present invention, and is a tire equatorial plane (tire equatorial plane CL) passing through the center along the tread width direction of the pneumatic tire and orthogonal to the axle of the vehicle. The gist is that the distance (distance d3) from the tip of the inner rim guard to the tip of the inner rim guard is substantially the same as the distance (distance d4) from the tire equatorial plane to the tip of the outer rim guard.

  A sixth feature of the present invention relates to the second feature of the present invention, and is summarized in that the outer height is 110% or more of the inner height.

  A seventh feature of the present invention relates to the second feature of the present invention, wherein an outer tire width (outer tire width W2) from the tire equator surface to the outer portion is from the tire equator surface to the inner portion. The gist is that it is wider than the inner tire width (inner tire width W1).

  The eighth feature of the present invention is that, in a state before vulcanization, an amount of inner rubber of the inner sidewall portion including the inner rim guard of the pneumatic tire and an outer rubber of the outer sidewall portion including the outer rim guard. The gist is that the amount is the same.

  According to the characteristics of the present invention, it is possible to provide a pneumatic tire that further improves steering stability in a region where the steering angle is small without reducing ride comfort.

1 is an exploded perspective view showing a part of a pneumatic tire according to an embodiment of the present invention. It is sectional drawing of the tread width direction of the pneumatic tire which concerns on embodiment of this invention. It is an enlarged view which shows the vicinity of the outer side wall part of the cross section of the tread width direction of the pneumatic tire which concerns on embodiment of this invention, and the vicinity of an inner side wall part.

  An embodiment of a pneumatic tire according to the present invention will be described with reference to the drawings. Specifically, (1) the structure of a pneumatic tire, (2) comparative evaluation, (3) action and effect, and (4) other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(1) Configuration of Pneumatic Tire FIG. 1 is an exploded perspective view showing a part of a pneumatic tire 1 according to this embodiment. FIG. 2 is a cross-sectional view of the pneumatic tire 1 in the tread width direction (W direction). As shown in FIGS. 1 and 2, the pneumatic tire 1 has a carcass layer 12 that is a skeleton of the pneumatic tire 1.

  The carcass layer 12 includes a carcass cord 11. An inner liner 13 that is a highly airtight rubber layer corresponding to a tube is provided inside the carcass layer 12 in the tire radial direction. Both ends of the carcass layer 12 are locked to the pair of bead portions 14.

  A belt layer 15 is disposed outside the carcass layer 12 in the tire radial direction. The belt layer 15 includes a first belt layer 15A and a second belt layer 15B obtained by rubberizing a steel cord. The steel cords constituting the first belt layer 15A and the second belt layer 15B are arranged at a predetermined angle (for example, ± 25 degrees) with respect to the tire equatorial plane CL.

  The pneumatic tire 1 has cap layers 18A and 18B. The cap layers 18A and 18B are rubberized organic fiber cords that are positioned on the outer side in the tire radial direction of the belt layer 15 and arranged substantially parallel to the tire equatorial plane CL. The cap layers 18 </ b> A and 18 </ b> B cover both end portions of the belt layer 15.

  A tread portion 16 that contacts the road surface is provided on the outer side in the tire radial direction of the belt layer 15 (the first belt layer 15A and the second belt layer 15B). The tread portion 16 has a tread rubber layer 16A.

  FIG. 2 is a cross-sectional view of the pneumatic tire 1 in the tread width direction (W direction). The pneumatic tire 1 has an inner side portion 20A and an outer side portion 20B. The inner side part 20 </ b> A has an inner side wall part 21. The outer side part 20 </ b> B has an outer side wall part 22. As shown in FIG. 2, the pneumatic tire 1 has a mounting direction determined when the vehicle is mounted. That is, the inner sidewall portion 21 is located on the vehicle inner side (in) when mounted on the vehicle. The outer sidewall portion 22 is located on the vehicle outer side (out) when mounted on the vehicle.

  The carcass layer 12 has an inner portion Cin in which the carcass cord 11 is located at the innermost side of the vehicle when mounted on the vehicle. The inner portion Cin is located inside the inner sidewall portion 21.

  The carcass layer 12 has an outer portion Cout where the carcass cord 11 is located on the outermost side of the vehicle when mounted on the vehicle. The outer portion Cout is located inside the outer sidewall portion 22.

  FIG. 3 is an enlarged view showing the vicinity of the inner sidewall portion 21 and the vicinity of the outer sidewall portion 22 in the cross-sectional view of the pneumatic tire 1 in the tread width direction (W direction).

  The outer height SWHout, which is the height of the outer portion Cout relative to the position of the bead portion 14, is higher than the inner height SWHin, which is the height of the inner portion Cin relative to the position of the bead portion 14.

  That is, SWHout> SWHin. Preferably, the outer height SWHout is 110% or more and 200% or less of the inner height SWHin.

  Furthermore, it is preferably 150% or less (it is considered preferable to describe the upper limit value).

  The inner side portion 20 </ b> A includes an inner sidewall portion 21 and an inner rim guard 31. An inner rim guard 31 is formed on the inner sidewall portion 21. The inner rim guard 31 is formed so as to protrude from the inner sidewall portion 21. The outer side portion 20 </ b> B has an outer sidewall portion 22 and an outer rim guard 32. An outer rim guard 32 is formed on the outer sidewall portion 22. The outer rim guard 32 is formed so as to protrude from the outer sidewall portion 22. The inner rim guard 31 and the outer rim guard 32 protect a rim wheel (not shown) on which the pneumatic tire 1 is assembled.

  Here, the cross-sectional area S1 of the inner rim guard 31 along the tread width direction (W direction) is larger than the cross-sectional area S2 of the outer rim guard 32 along the tread width direction (W direction).

  The distance d1 from the inner sidewall portion 21 to the protruding end 31a of the inner rim guard 31 and the distance d2 from the outer sidewall portion 22 to the protruding end 32a of the outer rim guard 32 are substantially the same.

  A distance d3 from the tire equatorial plane CL to the protruding end 31a of the inner rim guard 31 passing through the center along the tread width direction (W direction) of the pneumatic tire 1 and orthogonal to the vehicle axle, and the outer rim guard 32 from the tire equatorial plane CL. The distance d4 to the protrusion 32a is substantially the same.

  The outer tire width W2 from the tire equatorial plane CL to the outer portion Cout is wider than the inner tire width W1 from the tire equatorial plane CL to the inner portion Cin.

  As described above, the shapes of the inner portion Cin and the outer portion Cout of the carcass layer 12 of the pneumatic tire 1 are asymmetric. Specifically, the curvature radius of the curved portion from the tread portion 16 to the inner sidewall portion 21 of the pneumatic tire 1 is larger than the curvature radius of the curved portion from the tread portion 16 to the outer sidewall portion 22.

  In the pneumatic tire 1, the inner rubber amount of the inner side portion 20 </ b> A including the inner rim guard 31 and the outer rubber amount of the outer side portion 20 </ b> B including the outer rim guard 32 are equal to the tire equatorial plane CL. That is, in the pneumatic tire 1, the difference between the inner rubber amount and the outer rubber amount, which is caused by the asymmetric shapes of the inner portion Cin and the outer portion Cout of the carcass layer 12, is determined based on the volume of the inner rim guard 31 and the outer rim guard 32. Is absorbed by.

  Therefore, the pneumatic tire 1 does not need to change the amount of rubber inside and outside the vehicle even in a state before vulcanization (a state of a green tire). The inner rubber amount of the inner side portion 20A of the green tire and the outer rubber amount of the outer side portion 20B are the same.

(2) Comparative evaluation (2-1) Manufacture of pneumatic tire 1 having different cross-sectional shapes Pneumatic tires 1 having different cross-sectional shapes were manufactured. Specifically, the outer height SWHout, which is the height of the outer portion Cout with respect to the position of the bead portion 14, and the inner height SWHin, which is the height of the inner portion Cin with respect to the position of the bead portion 14, Pneumatic tires 1 having different relationships were manufactured.

  The cross-sectional area S1 of the inner rim guard 31 is larger than the cross-sectional area S2 of the outer rim guard 32.

  The distance d1 from the inner sidewall portion 21 to the protruding end 31a of the inner rim guard 31 and the distance d2 from the outer sidewall portion 22 to the protruding end 32a of the outer rim guard 32 are substantially the same.

  A distance d3 from the tire equatorial plane CL to the protruding end 31a of the inner rim guard 31 and a distance d4 from the tire equatorial plane CL to the protruding end 32a of the outer rim guard 32 are different values for each pneumatic tire.

(2-3) Steering stability and ride comfort test Pneumatic tires of Examples 1 to 3 were manufactured and mounted on a test vehicle to perform an actual running test. Steering stability and ride comfort are as follows: Test drivers run on a test track consisting of a circuit with a long straight line and a handling evaluation road with many gentle curves. Sensory evaluation was performed with 10 points as the perfect score for steering performance (handle response) and riding comfort.

  The test speed was set to a realistic speed range (low speed to about 100 km / h) experienced by a general driver on a public road.

The tire sizes and vehicles used in the test are as follows.

Tire size: 215 / 45R17
Rim size: 7J × 17
Air pressure: 240 kPa (same for front and rear wheels)
Test vehicle for actual running test: 2000cc displacement
Table 1 shows the specifications of the used pneumatic tire and the results of steering stability and ride comfort test.

  In Example 1, SWHout> SWHin and SWHout / SWHin = 112%. In Example 2, SWHout> SWHin and SWHout / SWHin = 120%. In Example 3, SWHout> SWHin and SWHout / SWHin = 150%. In Comparative Example 1, SWHout = SWHin. In Comparative Example 2, SWHout> SWHin and SWHout / SWHin = 165%.

  As shown in Table 2, the pneumatic tire according to the present invention was found to have significantly improved handling stability and riding comfort as compared with the pneumatic tire of the comparative example.

(3) Action / Effect In the pneumatic tire 1, the inner rim guard 31 is formed on the inner sidewall portion 21 located on the inner side when the vehicle is mounted, and the outer rim guard 32 is formed on the outer sidewall portion 22. ing. The cross-sectional area S1 of the inner rim guard 31 along the tread width direction (W direction) is larger than the cross-sectional area S2 of the outer rim guard 32 along the W direction.

  Thereby, the rigidity with respect to the bending deformation from the tread portion 16 to the inner sidewall portion 21 is increased. Therefore, the cornering force rises quickly during steering. Thereby, steering stability (responsiveness) in a region where the steering angle is small is improved.

  In a state where the pneumatic tire 1 is mounted on the vehicle, the height of the inner portion Cin where the carcass cord 11 is located on the innermost side of the car is lower than the outer portion Cout where the carcass cord 11 is located on the outermost side of the vehicle. Therefore, the radius of curvature of the curved portion of the carcass layer 12 from the tread portion 16 of the pneumatic tire 1 to the inner sidewall portion 21 is increased.

  Thereby, the rigidity with respect to the bending deformation from the tread portion 16 to the inner sidewall portion 21 can be increased. Therefore, the cornering force can be quickly raised during steering. Therefore, steering stability (responsiveness) in a region where the steering angle is small is improved.

  Further, in the pneumatic tire 1, the height of the outer portion Cout is higher than the height of the inner portion Cin. Therefore, the radius of curvature of the curved portion of the carcass layer 12 from the tread portion 16 of the pneumatic tire 1 to the outer sidewall portion 22 is reduced.

  Thereby, the rigidity with respect to the bending deformation from the tread portion 16 to the outer sidewall portion 22 is reduced. Therefore, the absorbency of the impact with respect to the unevenness | corrugation of a road surface increases. Thereby, riding comfort improves. That is, the pneumatic tire 1 can further improve the steering stability in the region where the steering angle is small without reducing the riding comfort.

  In the pneumatic tire 1, the outer tire width W2 from the tire equatorial plane CL to the outer portion Cout is wider than the inner tire width W1 from the tire equatorial plane CL to the inner portion Cin.

  The mold used in the vulcanization process of the pneumatic tire 1 is formed with a recess for forming the inner rim guard 31 and the outer rim guard 32. In the vulcanization process, raw rubber is drawn into these recesses, and the inner rim guard 31 and the outer rim guard 32 are formed.

  At this time, the carcass layer 12 follows the flow of raw rubber and is drawn into the recess. That is, the carcass layer 12 is drawn toward the inner rim guard 31 side and the outer rim guard 32 side. As a result, the curvature radius of the curved portion from the tread portion 16 to the inner sidewall portion 21 of the pneumatic tire 1 and the curvature radius of the curved portion from the tread portion 16 to the outer sidewall portion 22 can be changed. .

  In the mold, the volume of the recess for forming the inner rim guard 31 is larger than the volume of the recess for forming the outer rim guard 32. Therefore, in the vulcanization process, rubber tends to flow into the concave portion for the inner rim guard 31. Therefore, the radius of curvature of the carcass layer 12 in the inner sidewall portion 21 can be made smaller than the radius of curvature of the carcass layer 12 in the outer sidewall portion 22.

  In addition, the volume of the concave portion for forming the inner rim guard 31 is larger than the volume of the concave portion for forming the outer rim guard 32. Therefore, the amount of rubber flowing into the inner rim guard 31 formed on the inner sidewall portion 21 is larger than the amount of rubber flowing into the outer rim guard 32 formed on the outer sidewall portion 22. Therefore, it is possible to absorb the difference in the amount of rubber that becomes non-uniform due to the difference in the shape of the carcass layer 12 between the vehicle inner side and the vehicle outer side of the pneumatic tire 1.

  In the pneumatic tire 1, the distance d1 from the inner sidewall portion 21 to the protruding end 31a of the inner rim guard 31 and the distance d2 from the outer sidewall portion 22 to the protruding end 32a of the outer rim guard 32 are substantially the same. The distance d3 from the tire equatorial plane CL of the pneumatic tire 1 to the protruding end 31a of the inner rim guard 31 and the distance d4 from the tire equatorial plane CL to the protruding end 32a of the outer rim guard 32 are substantially the same.

  Thus, the pneumatic tire 1 is pneumatic even if the carcass layer 12 is formed asymmetrically between the vehicle inner side and the vehicle outer side with respect to the tire equatorial plane CL in the cross section in the tread width direction (W direction). The external shape of the tire 1 can be made substantially symmetrical.

  Therefore, it is possible to improve steering stability and riding comfort without greatly changing the design of the appearance. Furthermore, the user does not feel uncomfortable because the pneumatic tire 1 is asymmetric.

(4) Other Embodiments As described above, the contents of the present invention have been disclosed through one embodiment of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. should not do. From this disclosure, various alternative embodiments will be apparent to those skilled in the art.

  In the pneumatic tire 1, the outer height SWHout, which is the height of the outer portion Cout of the carcass layer 12 with respect to the position of the bead portion 14, is the height of the inner portion Cin of the carcass layer 12 with respect to the position of the bead portion 14. What is necessary is just to be higher than inner height SWHin which is height.

  That is, since it is the shape of the carcass layer 12 that substantially contributes to the rigidity of the tire, it is sufficient that SWHout> SWHin is satisfied, and the inner side wall portion 21 and the outer side wall portion 22 are in appearance. It may be the same shape. The height corresponding to the outer portion Cout and the inner portion Cin may be the same.

  The shape and cross-sectional area of the inner rim guard 31 formed on the inner sidewall portion 21 and the outer rim guard 32 formed on the outer sidewall portion 22 of the pneumatic tire 1 are not limited to the illustrated shapes. Any shape can be used as long as it does not impair the function as a rim guard and the function of uniforming the inner rubber amount of the inner side portion 20A and the outer rubber amount of the outer side portion 20B of the pneumatic tire 1 in the vulcanization process. It may be.

  In the pneumatic tire 1, the inner rim guard 31 and the outer rim guard 32 are not necessarily formed. It may also be excised after formation.

  The outer tire width W2 from the tire equatorial plane CL to the outer portion Cout of the pneumatic tire 1 may not necessarily be wider than the inner tire width W1 from the tire equatorial plane CL to the inner portion Cin.

  Further, in the pneumatic tire 1, the distance d1 from the inner sidewall portion 21 to the protruding end 31a of the inner rim guard 31 and the distance d2 from the outer sidewall portion 22 to the protruding end 32a of the outer rim guard 32 are substantially the same. . Further, the distance d3 from the tire equatorial plane CL of the pneumatic tire 1 to the protruding end 31a of the inner rim guard 31 and the distance d4 from the tire equatorial plane CL to the protruding end 32a of the outer rim guard 32 were substantially the same.

  However, the pneumatic tire 1 only needs to satisfy at least the relationship of SWHout> SWHin, and the external shape can be designed freely.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire, 11 ... Carcass cord, 12 ... Carcass layer, 13 ... Inner liner, 14 ... Bead part, 15 ... Belt layer, 15A ... 1st belt layer, 15B ... 2nd belt layer, 16 ... Tread Part, 16A ... tread rubber layer, CL ... tire equator line, 18A, 18B ... cap layer, 20A ... inside side part, 20B ... outside side part, 21 ... inside sidewall part, 22 ... outside sidewall part, Cin ... inside Part, Cout ... outer part, SWHout ... outer height, SWHin ... inner height, 31 ... inner rim guard, 31a ... protrusion, 32 ... outer rim guard, 32a ... protrusion, S1 ... cross-sectional area of inner rim guard, S2 ... outer rim guard Cross-sectional area, d1 ... distance from the inner side wall part to the tip of the inner rim guard, d2 ... outer side from the outer side wall part The distance to the tip of rim guard, d3 ... distance from the tire equatorial plane CL to the protruding end of the inner rim guard, d4 ... distance from the tire equatorial plane CL to the protruding end of the outer rim guard, W1 ... inner tire width, W2 ... outer tire width

Claims (7)

A pair of beads,
A pneumatic tire comprising a carcass layer including a carcass cord locked to the bead part,
An inner side rim guard that protrudes from the inner side wall part and protects a rim wheel to which the pneumatic tire is assembled is formed on the inner side wall part that is located inside when the vehicle is mounted,
An outer side rim guard that protrudes from the outer side wall part and protects the rim wheel is formed on the outer side wall part that is located outside when the vehicle is mounted.
Cross-sectional area of the inner rim guard along the tread width direction is much larger than the cross-sectional area of the outer rim guard along the tread width direction,
The inner rim guard has an inner portion where the carcass cord is located on the innermost side of the vehicle when mounted on the vehicle,
The outer rim guard has an outer portion where the carcass cord is located on the outermost side of the vehicle when the vehicle is mounted,
The outer height, which is the height of the outer portion with respect to the position of the bead portion, is 150% or less of the inner height, which is the height of the inner portion with respect to the position of the bead portion. tire.   The pneumatic tire according to claim 1, wherein an inner rubber amount of the inner sidewall portion including the inner rim guard and an outer rubber amount of the outer sidewall portion including the outer rim guard are the same.   The pneumatic tire according to claim 1, wherein a distance from the inner sidewall portion to the protruding end of the inner rim guard is substantially the same as a distance from the outer sidewall portion to the protruding end of the outer rim guard. The distance from the tire equatorial plane perpendicular to the vehicle axle to the tip of the inner rim guard through the center along the tread width direction of the pneumatic tire and the distance from the tire equatorial plane to the tip of the outer rim guard are: The pneumatic tire according to claim 1, which is substantially the same. The pneumatic tire according to claim 1 , wherein the outer height is 110% or more of the inner height. Outer tire width from the tire equatorial plane to the outer portion, the pneumatic tire according from the tire equatorial plane to claim 1 wider than the inner tire width up to the inner portion. The amount of rubber inside the inner sidewall portion including the inner rim guard of the pneumatic tire and the amount of outer rubber of the outer sidewall portion including the outer rim guard in the state before vulcanization are the same. 2. The pneumatic tire according to 2.

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