JP2002036835A - Run-flat tire for two-wheeler and two-wheeler equipped with the tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an ensurance of an excellent run-flat durability by inhibiting a reduction of a comfortability to ride during usual traveling. SOLUTION: The run-flat tire is provided with a carcass 4; a bead filler 6 disposed in adjacent to an outer periphery of a bead core between a body part 4b and a winding back part 4a of the carcass; and an inner liner 7 positioned at an inner surface side in a tire width direction of the carcass 4. A rubber-reinforcing layer 8 is arranged at an area corresponding to at least side wall part 2. A circumferential insert 9 constituted by a rubber coated layer of cord having a high elasticity and extending to a tire circumferential direction is arranged between around an outer periphery of a bead core 5 and the tread maximum width position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a run-flat tire for a motorcycle, which advantageously suppresses a decrease in ride comfort during normal running and ensures excellent run-flat durability.

[0002]

2. Description of the Related Art In motorcycle tires, when running in a state of reduced air pressure due to puncture or the like, that is, during run-flat, crushing deformation in the tire radial direction due to applied load causes severe bending of the sidewall portion of the tire. As a result of such bending, the tire bead may be detached from the rim. Therefore, it is necessary to sufficiently reinforce the sidewall portion in order to suppress the bending deformation of the sidewall portion at the time of run flat and to enable safe non-stop traveling to a vehicle repair station or the like.

[0003] In recent years, in order to respond to such a demand for reinforcing the sidewall portion against bending deformation in the radial direction, a rubber reinforcing layer having a considerably large maximum thickness and a substantially crescent-shaped cross section has been added to the sidewall portion. Attempts have been made to dispose them, or to dispose a rubber reinforcing layer having a high rubber level on the sidewalls.

[0004]

However, when a thick or high rubber reinforcing layer is simply provided on the side wall portion of a motorcycle tire and the rubber reinforcing layer is reinforced, the tire radial direction is reduced. Due to the excessive increase in the rigidity of the vehicle, there is a problem that the ride comfort of the vehicle at the time of normal running other than at the time of run flat is greatly reduced. Therefore, even when reinforcement is applied to the bending of the sidewall portion of the motorcycle tire, a technique for reinforcing the sidewall portion that can advantageously suppress a decrease in ride comfort during normal running has been desired.

The present invention solves the above-mentioned problem by sufficiently satisfying such a demand. It is an object of the present invention to provide a rubber reinforcing layer on a sidewall portion and a bead core. A circumferential insert is placed between the upper end and the tread maximum width position to reinforce the sidewalls and ensure excellent run-flat durability of the tires. An object of the present invention is to provide a run-flat tire for a motorcycle in which the decrease is effectively suppressed.

[0006]

SUMMARY OF THE INVENTION The present invention comprises a tread portion having a substantially arc-shaped cross-sectional profile, a sidewall portion, and a bead portion, and includes a bead core disposed in each bead portion. And a carcass made of an organic fiber cord in which the side portions are wound radially outward around the bead core, and an outer peripheral surface of the bead core between the carcass main body portion and the rewind portion. A bead filler and an inner liner located on the inner surface side of the carcass, at least in a region corresponding to the sidewall portion, a rubber reinforcing layer is disposed, and the outer periphery of the bead core and the tread maximum width position And a circumferential insert formed of a rubberized layer of a highly elastic cord extending in the tire circumferential direction.

In this run-flat tire for a motorcycle, a rubber reinforcing layer which is not thickened or whose hardness is not increased as compared with the conventional tire is provided on the side wall portion, and a bead core upper end portion is provided. By further arranging the circumferential insert between the tread maximum width position and the tread maximum width position, the thickness or hardness of the rubber reinforcing layer is smaller than in the conventional case where only the rubber reinforcing layer is provided on at least the sidewall portion. In order to at least compensate for the load supporting ability at the time of run flat based on the decrease in the rigidity of the sidewall portion due to the reduction in the tire diameter, the tire radius is increased by the tensioning action of the cord in the extending direction of the cord in the circumferential direction insert. Direction load is distributed in the circumferential direction and is supported. It is possible to ensure the rat durability. In addition, by the combination arrangement of the rubber reinforcing layer and the circumferential insert described above, the above effects and the weight reduction of the tire are ensured.

Further, in this run-flat tire for a motorcycle, by employing a combination of the rubber reinforcing layer and the circumferential insert, the circumferential rigidity is greatly increased due to the extending direction of the cord of the circumferential insert. And an increase in rigidity in the tire radial direction can be advantageously suppressed.In other words, based on the anisotropy of rigidity change due to the circumferential insert arrangement, compared to the case where only the rubber reinforcing layer is provided. Thus, it is possible to advantageously suppress a decrease in riding comfort during normal running without increasing the rigidity in the tire radial direction more than necessary.

Therefore, in this run-flat tire for a motorcycle, instead of disposing only the rubber reinforcing layer on at least the side wall portion, the rubber reinforcing layer whose thickness or hardness is advantageously reduced and the circumferential insert are disposed. With this arrangement, it is possible to advantageously suppress a decrease in ride comfort during normal traveling and still ensure excellent run flat durability.

[0010] More preferably, in such a run-flat tire for a motorcycle, at least one of the rubber layers constituting the rubber reinforcing layer extends between the bead portion and the vicinity of the tread side portion, and the rubber layer has a cross section in the tire width direction. The inner shape is almost crescent-shaped and the rubber reinforcing layer
% Modulus is 6 to 20 MPa, and the maximum thickness of the rubber reinforcing layer in the normal direction of the carcass is in the range of 4 to 15 mm. According to this, at least one of the rubber layers constituting the rubber reinforcing layer is extended between the bead portion and the vicinity of the tread side portion, thereby efficiently suppressing the crushing deformation of the sidewall portion during run flat. By making the shape of the rubber layer in the cross section in the tire width direction substantially crescent-shaped, it is possible to advantageously suppress the intrusion of air between the carcass ply and the rubber layer during tire molding, By setting the 100% modulus of the reinforcing layer at normal temperature to 6 to 20 MPa, the hardness of the rubber reinforcing layer is excessively increased, thereby preventing early failure of the tire due to rubber cracks and sufficiently obtaining the reinforcing effect of the sidewall portion. And the maximum thickness of the rubber reinforcing layer in the normal direction of the carcass is 4 to 15
When the thickness is in the range of mm, a sufficient reinforcing effect on the sidewall portion can be obtained without making the tire excessively heavy.

Preferably, in a no-load state filled with a predetermined air pressure, a side height ratio of a radial height from an inner peripheral edge position of the tire to a tire maximum width position to a tread maximum width is 0.3 or less. I do. According to such a motorcycle run-flat tire, the rigidity in the radial direction is excessively increased due to the reinforcement of the sidewall portion, and consequently, the reduction in ride comfort during normal running is remarkable, so-called low-flat tire, By employing the combination arrangement of the rubber reinforcing layer and the circumferential insert, the effect of suppressing a decrease in ride comfort during normal running is remarkably exhibited.

Here, in a no-load state filled with a predetermined air pressure, the curvature defined when the tread height ratio to the tread maximum width is in the range of 0.2 to 0.45 is as follows: This is suitable for traveling with a camber angle of a motorcycle provided. Here, the state in which the predetermined air pressure is charged means a state in a rim assembling posture of the tire, and the rim is defined by JA.
Refers to a standard rim or a designed rim defined by industrial standards and standards such as TMA, TRA, ETRTO, etc. Further, the measurement conditions of tread height and tread maximum width are as follows. It shall be in a no-load state filled with a predetermined air pressure specified in a standard or a standard.

When the heat shrinkage of the organic fiber cord constituting the carcass is set to 13% or less, the heat shrinkage of the organic fiber cord is low in the post-curing inflation process performed immediately after vulcanization during tire production. Therefore, the tire case portion is not severely contracted and deformed, and therefore the deformation of the bead portion is suppressed, and the roundness of the tire is not impaired, and a good fit between the tire and the bead seat of the post cure inflator is realized. Also, after the post cure inflation, when using the tire, due to the low heat shrinkage of the organic fiber cord,
The excellent alignment shape of the bead core is maintained without the bead core being pulled by the organic fiber cord, and thereby, the rim fit of the tire can be advantageously secured. The rim can be advantageously prevented from slipping off during run flat by securing the tightening force.

Also, even when heat is generated due to friction between the organic fiber cord of the carcass and the rubber during run flat, the organic fiber cord constituting the carcass does not undergo severe heat shrinkage, thus disturbing the alignment state of the bead core. As a result, the rim can be advantageously prevented from coming off during run flat by ensuring excellent tightening force on the rim. Incidentally, the heat shrinkage rate here means ASTM D
According to 4974-93, 177 with an initial load of 50g
It is a shrinkage ratio when exposed to an atmosphere of ° C. for 2 minutes.

When the constant load elongation rate of the organic fiber cord is set to 10% or less, sufficient rigidity of the tire case can be secured to suppress the crushing of the side wall portion during run flat. . Here, the constant load elongation is a constant load elongation defined by JIS-L1017-7.7.

At least two of the carcass plies constituting the carcass have a structure in which organic fiber cords cross each other, and the inclination angle of the organic fiber cords of the two carcass plies with respect to the tire circumferential direction is 20 to
When the angle is in the range of 45 °, both the circumferential rigidity and the radial rigidity of the tire can be sufficiently ensured.

In addition, since the rigidity of the sidewall portion is very high as compared with the rigidity of the tread portion, it is difficult to ensure the ride comfort during excellent normal running. In run flat tires,
When at least one of the carcass plies constituting the carcass has a radial structure in which the organic fiber cord extends at 90 ° to the tire circumferential direction, when the tire case rigidity is relatively low, the radial rigidity is reduced. As a result, it is possible to effectively secure the ride comfort during normal running, and at this time, the filling rate of the rubber for coating the carcass ply is set to 20% or more, so that the run flat At the time of bending deformation of the side wall portion, it is possible to advantageously prevent damage failure of the side wall portion caused by mutual contact of the organic fiber cords constituting the carcass, and further, on the outer peripheral side of the crown portion of the carcass, By arranging the belt made of the organic fiber cord, an excellent reinforcing effect can be provided to the tread portion. In addition, the filling rate referred to here is a sum Lc of the length in the width direction of the organic fiber cord portion per unit width of the carcass ply in a cross section perpendicular to the extending direction of the organic fiber cord constituting the carcass, By the sum Lg of the width in the width direction of the rubber portion coating the carcass ply,
It is a value defined by {Lg / (Lc + Lg)} × 100.

In the above-described run flat tire for a motorcycle, the upright side of the bead portion facing the rim flange outside in the tire width direction is in a posture parallel to the upside inside the rim flange in the tire width direction, and The angle (α) formed by the bead base surface with respect to the tire rotation axis and the bead seat surface of the rim being adjusted with respect to the tire rotation axis in a state where the interval between the upright side surfaces of the bead portion is equal to the interval at the time of assembling the rim. Be larger than the angle (β)
When the angle difference between them is 2 ° or more and less than 15 °,
Excellent air sealability can be achieved, and the rim assembly and rim assembly of the tire can be easily performed.Moreover, when tightening the tire with the rim, the rubber in the tire radially inner part than the bead core is removed. Since the compression can be performed substantially uniformly, the rim can be easily tightened. In addition, the above-mentioned compression is to ensure the rim slip resistance of the tire sufficiently by making the fluctuation of the rubber in the radially inner portion of the tire than the bead core during the running less than 1% based on the tightened state of the rim. By doing so, slippage of the rim of the tire can be advantageously prevented.

Further, when the angle difference is set to approximately 0 °, the rubber in the radially inner portion of the tire can be more uniformly compressed than the bead core when the tire is tightened by the rim. Can be realized more easily.

Further, when the bead core is formed of a monofilament spirally wound structure and the cross-sectional shape of the bead core is polygonal and the inner peripheral surface of the bead core is flat, the bead core is tightened when the rim is tightened. By making the inner peripheral surface and the bead seat surface of the rim parallel,
Since the rubber in the radially inner part of the tire can be compressed evenly than the bead core, not only can the rim be easily tightened, but also the monofilament spiral winding structure with excellent tensile strength By maintaining the rim tightening force at a high level, the rim of the tire can be advantageously prevented from coming off.

In such a bead portion structure, the upright side of the bead portion facing the rim flange on the outer side in the tire width direction is oriented parallel to the inner side of the rim flange in the tire width direction. In the state where the interval of the upright side surface is equal to the interval at the time of rim assembly, the bead base inner diameter on the center line in the tire width direction of the bead core, at the time of rim assembly of the tire, on the center line in the tire width direction of the bead core 0 to 4.0 mm smaller than the bead seat outer diameter of the rim flange, or in this state,
The bead core inner diameter on the center line in the tire width direction of the bead core was increased by 2.0 to 6.0 mm with respect to the bead seat outer diameter of the rim flange on the center line in the tire width direction of the bead core when assembling the rim of the tire. In this case, when the tire is assembled on the rim, a sufficient rim tightening force can be obtained, so that the rim does not come off during run flat, and the rim can be easily assembled.

When the tire is assembled on the rim, the compression ratio of the radially inner portion of the bead core in the tire radial direction is set to 20%.
When it is within the range of ５０50%, the rim can be easily assembled and the rim can be easily released, and the rim tightening force can be sufficiently secured. Here, the compression ratio means the bead core inner diameter Dc and the tire bead base inner diameter D on the center line in the tire width direction of the bead core.
b and the bead seat outer diameter Dr of the rim flange, the following equation {(Dc−Db) / 2} − {(Dc−Dr) / 2} /
(Dc−Db) / 2}] × 100.

In the case where the thickness of the inner liner is 1.5 mm or more in a region of 5 mm in the radial direction at the outer end position of the rubber reinforcing layer in the tire radial direction, the tire case expansion in the tire vulcanization molding process is performed. At the time, the step formed between the radial end of the rubber reinforcing layer and the inner surface of the carcass ply does not hinder the flow deformation of the rubber constituting the inner liner, thus preventing the rubber reinforcing layer from cracking. In addition, tires used for motorcycles that perform a cornering run by giving a camber angle,
Intense bending of the sidewall portion during normal running, particularly during run flat, causes stress concentration at the step portion. Even during this stress operation, rubber cracking failure of the rubber reinforcing layer can be advantageously prevented. In addition, when the thickness of the inner liner is 2.0 mm or more, the rubber cracking failure of the rubber reinforcing layer can be more effectively prevented.

By the way, the two-wheeled vehicle in which the above-described run-flat tire for a two-wheeled vehicle is mounted on the front wheel and the rear wheel has an advantage that the minimum maneuverability and driving force required for traveling can be secured when the internal pressure is reduced. is there. Further, a two-wheeled vehicle in which the run-flat tire for a two-wheeled vehicle is mounted only on the rear wheel has an advantage that a minimum driving force required for traveling can be secured even when the internal pressure of the rear wheel is reduced.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view in the tire width direction showing an embodiment of the present invention, in which 1 is a tread portion having a substantially arc-shaped cross-sectional profile, and 2 is a radially inner portion from a side portion of the tread portion. 3 indicates a bead portion located on the inner peripheral side of the sidewall portion 2.

Here, each of the parts 1, 2, 3 extends toroidally from one bead part 3 to the other bead part 3.
The side portion 4a of the carcass 4 for reinforcing the
And a bead filler 6 having a substantially triangular JISA hardness of 60 ° or more and a bead core 5 between the body portion 4b and the rewind portion 4a of the carcass 4, The inner liner 7 is disposed on the inner surface side of the carcass 4.

Here, at least in a region corresponding to the side wall portion 2, between the inner liner 7 and the carcass main body portion 4 b, the carcass main body portion 4 b
When the carcass 4 is composed of a plurality of carcass plies (not shown), or between the main portions of the carcass plies, or between the rewind portions of the carcass plies. The rubber reinforcing layer 8 is provided between them. Here, preferably, at least one of the rubber layers constituting the rubber reinforcing layer 8 is extended between the bead portion 3 and the vicinity of the side portion of the tread portion 1 so that the rubber layer has a cross section in the tire width direction. And the 100% modulus of the rubber reinforcing layer 8 at room temperature is set to 6 to 20 MPa, and the carcass 4 of the rubber reinforcing layer 8 is formed.
Is in the range of 4 to 15 mm in the normal direction.
Incidentally, the crescent-shaped rubber layer in the tire width direction can change its width in the tire radial direction, that is, its thickness as appropriate.

In addition, as shown in FIGS. 2A to 2C, a rubber of a highly elastic cord extending in the tire circumferential direction between the vicinity of the outer periphery of the bead core 5 and the tread maximum width position. A circumferential insert 9 constituted by at least one cord reinforcing layer composed of a pull layer is provided outside the carcass rewind portion 4a in the tire width direction, between the carcass rewind portion 4a and the bead filler 6, or between the bead filler 6 and the carcass. It is arranged at any position between the main body portion 4b and the outer peripheral side of the crown portion of the carcass 4,
A belt 10 composed of at least one belt layer made of an organic fiber cord that extends obliquely or parallel to the tire circumferential direction is provided.

Here, the side height ratio of the radial height SH from the inner peripheral edge position of the tire to the tire maximum width position to the tread maximum width TW is 0.3 or less, and in the same state, the tread height The tread height ratio of the TH to the tread maximum width TW is in the range of 0.2 to 0.45.

The heat shrinkage of the organic fiber cord constituting the carcass 4 is set to 13% or less, and the constant load elongation of the organic fiber cord is set to 10% or less. At least two of the organic fiber cords cross each other,
The inclination angle of each organic fiber cord of the two carcass plies with respect to the tire circumferential direction is set in a range of 20 to 45 °, and preferably, at least one of the carcass plies constituting the carcass 4 is formed of an organic fiber cord. Has a radial structure extending at 90 ° to the tire circumferential direction, and the filling rate of the rubber coating the carcass ply is set to 20% or more.

In the run-flat tire for a motorcycle constructed as described above, as shown in FIG.
The vertical side facing the rim flange on the outside in the tire width direction is set to be in a posture parallel to the vertical side inside the tire width direction of the rim flange, and the interval between the vertical sides of the bead portion 3 is the interval at the time of rim assembly. The angle α formed by the bead base surface with respect to the tire rotation axis and the angle β formed by the bead seat surface of the rim with respect to the tire rotation axis.
And their angle difference α-β is 2
° or more and less than 15 °, preferably the angle difference α-β
Is preferably set to approximately 0 °, and preferably, the bead core 5 is constituted by a monofilament spirally wound structure, the cross-sectional shape of the bead core 5 is made polygonal, and the inner peripheral surface of the bead core 5 is made flat.

In this case, the upright side of the bead portion 3 facing the rim flange on the outside in the tire width direction is parallel to the upside of the rim flange on the inside in the tire width direction,
Further, in a state where the interval between the upright side surfaces of the bead portion 3 is equal to the interval at the time of assembling the rim, the bead base on the center line L in the tire width direction of the bead core 5 (hereinafter referred to as “center line L”). The inner diameter Db is 0 to the bead seat outer diameter Dr passing through the bead seat point R of the rim which comes into contact with the bead base point B on the center line L when assembling the tire.
4.0 mm smaller, preferably in this state,
The bead core inner diameter Dc on the center line L is increased by 2.0 to 6.0 mm with respect to the bead sheet outer diameter Dr.

When the tire is assembled on the rim, the compression ratio of the inner portion in the tire radial direction with respect to the bead core 5 is set as follows:
It is within the range of 20 to 50%.

The thickness of the inner liner 7 is set to 1.5 mm, preferably 2.0 mm or more in a region of 5 mm in the radial direction at the outer end of the rubber reinforcing layer 8 in the tire radial direction.

According to the run-flat tire for a motorcycle constructed as described above, the sidewall portion is reinforced by employing the combination arrangement of the rubber reinforcing layer 8 and the circumferential insert 9, so that the tire can be used during normal running. In addition, it is possible to advantageously suppress the decrease in ride comfort of the tire and to ensure excellent run flat durability of the tire.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Except that the cross-sectional shape of the bead core is hexagonal, the tire core having the structure shown in FIG.
When the run-flat durability and the riding comfort during normal running of each of the example tire and the comparative example tire having the specifications shown in Table 1 were evaluated. It was as shown in the feeling result.
Incidentally, the bead core of each tire has a structure in which three, four, and three monofilaments are arranged in parallel in the tire width direction in a cross section in the tire width direction, and are laminated in three stages.

The run flat durability was evaluated by using the MT
The speed of the tire mounted on the rim of 3.00 is 80 km /
h, load: 3750N, internal pressure: 0 kPa, diameter 170
A drum test is performed by pressing the drum against a 0 mm drum, and the distance to the occurrence of a failure is measured.
(00 cc) with a tire (filling air pressure is described in Table 1), and the test was performed by a test rider running on a test course.

[0038]

[Table 1]

According to Table 1, each of the example tires 1 and 2 has an improved riding comfort as compared with the comparative example tires 1 and 2, and has excellent running performance equivalent to each of the comparative example tires. Flat durability can be ensured.

[0040]

As is apparent from the above description, according to the present invention, particularly, in the side wall portion,
By arranging the rubber reinforcement layer and arranging the circumferential insert between the vicinity of the upper end of the bead core and the position of the tread maximum width, it is possible to advantageously suppress the decrease in the riding comfort during normal running, Run flat durability can be ensured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention for a half portion of a tire.

FIG. 2 is a cross-sectional view showing an example of disposition of a circumferential insert used in the tire of the present invention.

FIG. 3 is a cross-sectional view showing a bead portion and a tire rim of the tire of the present invention in a state where the rim is not assembled.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass 4a Rewind part 4b Body part 5 Bead core 6 Bead filler 7 Inner liner 8 Rubber reinforcement layer 9 Circumferential insert 10 Belt B Bead base point L Center line in tire width direction R Bead seat point Db Bead base inner diameter Dc Bead core inner diameter Dr Bead seat outer diameter SH Height from innermost position in tire radial direction to maximum tire width position TH Tread height TW Maximum tread width α The tire bead base surface forms with respect to the tire rotation axis. Angle β The angle between the bead seat surface of the rim and the tire rotation axis.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B60C 15/04 B60C 15/04 C 15/06 15/06 NJ

Claims (17)

[Claims] A tread portion having a substantially arc-shaped cross-sectional profile, a sidewall portion, and a bead portion, wherein the tread portion extends toroidally between bead cores disposed in the respective bead portions, A carcass made of an organic fiber cord in which a side portion is wrapped radially outward around a bead core, and a bead filler arranged adjacent to an outer peripheral surface of the bead core, between a carcass body portion and a wrapped portion of the carcass. In a run-flat tire for a motorcycle including an inner liner located on the inner surface side of the carcass, a rubber reinforcing layer is provided at least in a region corresponding to the sidewall portion, and the vicinity of the outer periphery of the bead core and the tread maximum width position. Between,
A run flat tire for a motorcycle, comprising a circumferential insert formed of a rubberized layer of a highly elastic cord extending in the tire circumferential direction. At least one rubber layer constituting the rubber reinforcing layer extends between the bead portion and the vicinity of the tread side portion, and the shape of the rubber layer in the cross section in the tire width direction is substantially crescent-shaped. The rubber reinforcing layer has a 100% modulus at room temperature of 6 to 20 MPa, and the maximum thickness of the rubber reinforcing layer in the normal direction of the carcass is 4 to 15 m.
The run-flat tire for a motorcycle according to claim 1, wherein the range is m. 3. In a no-load state filled with a predetermined air pressure, a side height ratio of a radial height from an inner peripheral edge position of the tire to a tire maximum width position to a tread maximum width is set to 0.3 or less. Item 3. A run flat tire for a motorcycle according to item 1 or 2. 4. A tread height ratio of a tread height to a tread maximum width in a no-load state filled with a predetermined air pressure is in a range of 0.2 to 0.45.
The run-flat tire for a motorcycle according to any one of claims 1 to 3. 5. The motorcycle according to claim 1, wherein the heat shrinkage of the organic fiber cord constituting the carcass is 13% or less, and the constant load elongation of the organic fiber cord is 10% or less. For run flat tires. 6. At least two of the carcass plies constituting the carcass have a structure in which organic fiber cords cross each other, and the inclination angle of each of the two carcass plies with respect to the tire circumferential direction of the organic fiber cord is set to 20. ~ 4
The run-flat tire for a motorcycle according to any one of claims 1 to 5, which has a range of 5 °. 7. At least one of the carcass plies constituting the carcass has a radial structure in which an organic fiber cord extends at 90 ° to a tire circumferential direction, and a filling rate of a rubber coating the carcass plies is 20% or more. And a belt formed of an organic fiber cord is disposed on the outer peripheral side of the crown portion of the carcass.
7. The run flat tire for a motorcycle according to any one of the above items 6. 8. An upright side of the bead portion facing the rim flange on the outside in the tire width direction is oriented parallel to an upright side of the rim flange on the inside in the tire width direction, and The angle (α) formed by the bead base surface with respect to the tire rotation axis in a state where the space is equal to the space at the time of assembling the rim is defined by the angle (β) formed by the bead seat surface of the rim with respect to the tire rotation axis. The run-flat tire for a motorcycle according to any one of claims 1 to 7, wherein the angle difference between them is increased to 2 ° or more and less than 15 °. 9. The run-flat tire for a motorcycle according to claim 1, wherein the angle difference is substantially 0 °. 10. The bead core according to claim 1, wherein the bead core is constituted by a monofilament spirally wound structure, the cross section of the bead core is polygonal, and the inner peripheral surface of the bead core is flat. Run flat tire for motorcycles. 11. The outer side of the bead portion in the tire width direction,
In a state where the upright surface facing the rim flange is in a posture parallel to the upright surface inside the tire width direction of the rim flange, and the interval between the upright surfaces of the bead portion is equal to the interval at the time of rim assembly, The inner diameter of the bead base on the center line in the tire width direction of the bead core is made smaller by 0 to 4.0 mm than the outer diameter of the bead seat of the rim flange on the center line in the tire width direction of the bead core when assembling the rim of the tire. The run-flat tire for a motorcycle according to any one of claims 1 to 10. 12. The outer side of the bead portion in the tire width direction,
In a state where the upright surface facing the rim flange is in a posture parallel to the upright surface inside the tire width direction of the rim flange, and the interval between the upright surfaces of the bead portion is equal to the interval at the time of rim assembly, The bead core inner diameter on the center line in the tire width direction of the bead core is 2.0 to 6.0 mm with respect to the bead seat outer diameter of the rim flange on the center line in the tire width direction of the bead core when assembling the tire.
The run-flat tire for a motorcycle according to any one of claims 1 to 11, which is enlarged. 13. When the tire is mounted on the rim, the compression ratio of the radially inner portion of the tire relative to the bead core is set to 20 to 20.
The run-flat tire for a motorcycle according to any one of claims 1 to 12, which has a range of 50%. 14. The inner liner has a thickness of 1.5 mm or more in a radial inner and outer 5 mm region of the rubber reinforcing layer at the tire radial outer end position.
The run flat tire for a motorcycle according to any one of the above. 15. The run-flat tire for a motorcycle according to claim 14, wherein the inner liner has a thickness of 2.0 mm or more in a radially inner and outer 5 mm region of the rubber reinforcing layer at a radially outer end position of the tire. 16. A two-wheeled vehicle comprising the run-flat tire for a two-wheeled vehicle according to claim 1 mounted on a front wheel and a rear wheel. 17. A two-wheeled vehicle comprising the run-flat tire for a two-wheeled vehicle according to claim 1 mounted only on rear wheels.