JPS625B2 - - Google Patents

Abstract

A pneumatic run flat tire for motorcycles having a high handling stability during straight and zigzag runnings, cornering stability and durability, even when the tire is punctured while running and the pneumatic pressure inside of the tire becomes equal to atmospheric pressure. The run flat tire has a pair of sidewall-reinforcing layers, each comprising an elastic filler extending from an end location adjacent a bead core in a bead portion to the other end location in a tread portion through a sidewall portion of the tire, the elastic filler being reinforced with at least two reinforcing plies, one of which extends along one side surface of the elastic filler toward the tread portion, and then, additionally extends into the tread portion, and the other one of which extends along the other side surface of the elastic filler toward the bead portion, and the, additionally extends into the tread portion.

Description

[Detailed description of the invention]

The present invention relates to a tire that can be run even if a tire attached to a vehicle is punctured while driving, that is, a run-flat tire, particularly a run-flat tire for a two-wheeled vehicle (hereinafter referred to as a two-wheeled vehicle).
The carcass of the tire has a bias structure, and the side parts of the tire are strengthened to prevent the tire from completely collapsing even if the tire's air pressure drops to zero (equal to atmospheric pressure) due to a puncture, etc. In addition, the present invention provides a run-flat tire suitable for mass production among tires having a tire body structure that can follow the maneuverability peculiar to two-wheeled vehicles. Currently, the pneumatic tires in general use fill the air chambers of the tires with compressed air, and use the air elasticity of the tires to support the load of the vehicle and provide a good ride. The stiffness of the part is becoming very small. Therefore, when the air filled in the tire is released and its internal pressure becomes 0 kg/cm ² , the side portion of the tire collapses and bends outward. When the tires are in this condition, they are no longer able to rebound against the lateral forces that are applied to them, so they are unable to resist the lateral forces that are applied to the tires when the vehicle is cornering, making the vehicle unstable and leading to accidents. It becomes such a dangerous drive. In addition, a crushed tire causes flapping motion between the rim and the road surface, causing unnecessary vibration and wobbling phenomena to the vehicle and its control system, impairing ride comfort and running stability. Furthermore, if the tires continue to run for several kilometers at high speed in such conditions, they may be damaged due to excessive heat generation, or they may be torn and destroyed by external forces such as loads and rotational force.
A little repair will make it unusable. Also,
Due to the above-mentioned irregular movement of the tire, the tire easily comes off the rim and even flies out, which further causes a lack of stability in maneuverability and increases the danger. Recently, various proposals have been made for the purpose of improving the above-mentioned drawbacks regarding pneumatic tires for four-wheeled vehicles, and have achieved some success. In other words, there are types that simply prevent the tire from coming off the rim, types that have a load support placed inside the air chamber of the tire to prevent the tire from completely collapsing, and types that are designed to simply prevent the tire from coming off the rim. There are types that prevent the tire from coming off and support the load, or types that strengthen the internal structure of the tire itself, especially the side parts, to prevent the tire from collapsing. By the above means,
In the case of tires for four-wheeled vehicles, even if the air in the tire is completely lost due to a puncture, etc., it maintains the straightness of the vehicle, ensures cornering characteristics for turning curves, prevents the rim from coming off, and has durability. It has been effective in eliminating dangerous elements, such as improving safety. However, in the case of two-wheeled vehicles, unlike four-wheeled vehicles, the side force of the tires that occurs when cornering is not only the cornering force, but is mostly occupied by the camber force, and because the vehicle runs on two wheels. , more advanced tire characteristics such as straight-line stability are required, so it is difficult to not only withstand the load of the vehicle but also to determine the side reinforcement conditions, making it difficult to obtain the ideal run-flat tire for two-wheeled vehicles. was difficult. recently,
In run-flat tires for motorcycles, a proposal has been made to increase the rigidity of the side parts by arranging a high-hardness elastic reinforcing member from the tire crown to the bead. However, it was not necessarily sufficient to satisfy the requirements of durability and the like in a well-balanced manner. The present invention aims to eliminate the drawbacks of the above-mentioned prior art, and its objectives are as follows. That is, first, to obtain a run-flat tire that can run safely even when punctured, and which has dynamic characteristics no different from ordinary pneumatic tubeless tires when used in an inflated state; 2. If all the air in the tire is released,
For example, even when driving at speeds of 150 to 200 km/h, it has good straight-line stability without causing steering wheel shake or vehicle body vibration, and is easy to control without causing sudden changes in tire characteristics even during deceleration and acceleration. Thirdly, when all the air in the tire is released, when driving at a speed of 90 km/h to 100 km/h, the steering wheel will not shake or vibrate and will maintain straight-line stability. It runs well and is stable even when cornering, and it is also possible to drive 100 times with a flat tire like that.
It is important to obtain durability that allows the tire to travel distances of more than Km without fatal damage, and in particular, fourthly, no matter how good the performance is as a run-flat tire, the processing efficiency of the tire must be greatly reduced. Therefore, the purpose of this invention is to minimize such an increase in tire cost and to obtain a tire that satisfies the above-mentioned performance. The structure of the run-flat tire for two-wheeled vehicles according to the present invention has a vehicle speed of approximately 90% when the air is fully filled, as well as when all the air is released.
In order to maintain the tire's driving performance such as maneuverability and stability, as well as the durability to run for more than 100 km in a runflat state, the crown is attached to the side part that supports the load, the camber force. The bead section, which is necessary for cornering force, has been reinforced to the minimum necessary extent, and instead of stiffening the entire tire like a rigid body as in the past, It is not the type that requires a support body to receive the load or a special shape of the flange of the rim to receive the load. That is, in contrast to conventional pneumatic tires, where most of the side parts of conventional pneumatic tires have flexibility and therefore collapse into a flattened shape if all the air is released, the present invention provides flexibility even when the side part of the tire receives a load. In order to provide rigidity to the extent that it will not collapse, it features an elastic filler from the bead to the shoulder of the tire, and a side reinforcement section sandwiched in sandwich-like reinforcement ply to further reinforce the filler. That is. Since tires for two-wheeled vehicles do not have support in the left-right and lateral directions unlike those for four-wheeled vehicles, the stability of the tires in the left-right and lateral directions is important. Furthermore, when cornering, the vehicle body is tilted in the opposite direction to the direction of the centrifugal force in order to maintain the balance of the vehicle body against the generated centrifugal force, so a camber angle is imparted to the tires. To provide this camber angle, the tire's tread is designed to be wide and round. However, as a result of complicating the configuration of run-flat tires, productivity is significantly lowered, which impedes mass adoption and makes it impossible to increase the effect. In order to make a two-wheeled vehicle tire having the above-mentioned characteristics into a run-flat tire, the steps are summarized as follows. In other words, it must have the same external shape as a regular pneumatic tire. To prevent the tire from completely collapsing even if the tire's deflection increases from normal when the air is lost due to a puncture or the like. In the event of a flat tire, the vehicle should be stable enough to not wobble when driving straight or cornering, and to be able to smoothly turn corners. In the event of a flat tire, the vehicle should be able to run stably for a while without shaking the steering wheel or shaking the vehicle body, even when driving at high speeds of 150 to 200 km/h. Furthermore, when decelerating from high speed driving to medium speed below 100km/h,
Tire characteristics should not undergo sudden changes. 100km with a flat tire at a speed of 90-100km/h
Being able to travel further distances. To be able to easily assemble and remove tires and rims without going to a special service factory. To have a means to prevent the tire from easily coming off the rim when driving with a flat tire. To enable a punctured tire to be reused by a simple repair similar to repairing an ordinary tubeless tire, and to maintain quality equivalent to high-speed durability before the puncture. Must be a tubeless tire. To mold and process a tire without requiring any special equipment or machinery, and to be able to sufficiently mold it with a conventional molding machine without significantly reducing its molding efficiency. The structure of a run-flat tire for two-wheeled vehicles that satisfies the above requirements is as follows. In other words, the carcass that forms the frame of the tire body has a bias structure (the carcass cord has an angle in the range of 25° to 60° with respect to the tire's center line, or equator line), and the plies of the carcass (the carcass The number of layers (layers of rubberized cord) shall be 2 or more plies. The carcass is folded back and rolled up at a pair of left and right bead wires, and between the folded carcass, a reinforcing layer consisting of a combination of ply and elastic filler is placed near the bead wires or on an extension from the same position. to be placed. The reinforcing layer that reinforces both sides of the tire must extend from the bead, past the shoulder, and into the tread. The cord angle of the ply combined with the side reinforcement layer is determined to increase the bending rigidity of the tire side.
It should be larger than the angle of the carcass cord. The hardness of the elastic filler in the side reinforcement layer should be as large as possible (this usually increases the hardness of the rubber from 55 to 75).
(This means raising the elastic modulus or modulus of rubber to around 70 to 80.) The effect of doing so is
This is because the sidewall thickness can be made thinner. In general, as the rubber hardness or modulus of the elastic filler in the side reinforcement layer increases, the crack resistance decreases, but if it decreases too much, the life of the tire will decrease in relation to the durability of the side. Side outer skin rubber (side rubber)
80 to 100% of the flex scratch count (the number of times a rubber sample is bent when attached to a flex scratch tester). (The reason why the flex crack frequency value of the elastic filler was set to 80% of the value of the side outer skin rubber is that
This is because the stiffness of the side reinforcing layer contributes to reducing the strain that the filler receives. ) For large tires, a breaker layer should be provided between the tread and the carcass to reinforce the tread. (The reason for this is that larger tires have less bending elasticity in the tread than small tires, and this prevents the tire's maneuverability from decreasing.) The effect itself is better if the elastic filler is folded to wrap around the tread side end, but it is time-consuming to pre-form the ply elsewhere, or to fold it as is on the molding machine. It takes a lot of effort to wrap the ply into a cylindrical shape and wrap it around the elastic filler against the adhesiveness of the ply itself, which takes a lot of time. Therefore, in order to improve the molding efficiency of the tire, the side reinforcement ply is not bent and is instead sandwiched with an elastic filler. Regarding the positional relationship between the elastic filler and the side reinforcing ply, the side reinforcing ply extends longer than the elastic filler at the end on the shoulder side. (The reason for this is to maintain the bending effect of the side reinforcing ply.) The shoulder side end of the elastic filler is gradually made thinner as it extends toward the tread side, in order to avoid sudden changes in the side reinforcing effect. There is. The run-flat tire for two-wheeled vehicles constructed as described above can be used in the same way as a normal tubeless tire, except for the increased weight and the increased thickness of the case of the tire body. Due to its special structure, even if the tire loses air due to a puncture, etc.
The vehicle can be driven without sudden changes in tire motion performance and without damage to the tires. Especially on expressways, if you suddenly get a flat tire while driving at a high speed of, say, 200 km/h, it would be impossible to apply the brakes, and even if you continue to drive, it will lack stability. In the worst case, your life will be at risk if you fall over, but with the run-flat tire according to the present invention, the sidewall reinforcement takes into consideration balance, and its rigidity continues to extend to the tread area, and the bead area It is possible to secure driving stability, cornering performance, braking performance, etc. by strengthening the lateral side, so there is no danger as mentioned above, and by adding appropriate side rigidity.
Since the vehicle can travel distances of more than 100 km without damage at speeds of less than 100 km/h, it is possible to reach the service area and resume normal driving after a tire puncture is repaired. Furthermore, in order to ensure that the tire of the present invention exhibits cornering performance during run-flat driving, when the tire and rim are combined, the bead of the tire is easily pushed out of the seat where it fits on the rim. It is a good idea to use a device to prevent this.
Devices used for this purpose include means to prevent the beads of the tire from moving, or a spacer ring inserted between both beads of the tire. Even if a high-performance run-flat tire like the one mentioned above is very expensive, it cannot be expected that it will be widely used, so it is necessary to reduce the cost as much as possible.In particular, in order to reduce manufacturing costs, tire A run-flat tire with a good balance of characteristics and cost is required. According to the tire of the present invention, while maintaining the above-mentioned characteristics of the tire, the manufacturing method and equipment for conventional tubeless tires can be used as they are, so that it can be manufactured as a run-flat tire. There is nothing that increases costs other than the increase in man-hours due to the increase in parts. The present invention will be further described below with reference to the accompanying drawings. FIG. 1 shows a sectional view of a run-flat tire for two-wheeled vehicles according to an embodiment of the present invention.
The overall structure consists of a tread portion A, a pair of left and right shoulder portions B, a pair of left and right side portions C, and a pair of left and right bead portions D, but since it has a symmetrical cross-sectional structure, the following explanation will be given to only one side. 2
is the carcass, which is made up of a laminated ply 3 (Fig. 2) composed of tire cord and coated rubber, and forms the frame of the tire; 4 is tread rubber;
6 is a side rubber, and 6 is a breaker which is made of a laminated ply composed of tire cord and coat rubber, and which reinforces the tread portion A. Reference numeral 7 denotes a side reinforcing layer, which is an important component characterizing the present invention.As shown in FIG. The rubber filler 8 and reinforcing plies 9, 9' are made of tire cord and coated rubber, and are sandwiched from the left and right sides. A developed view of the rubber filler 8 and the reinforcing plies 9, 9' is shown in section E of FIG. 10 is a chief for a tubeless tire composed of a cord and coated rubber; 11 is a bead wire; 12 is an air-impermeable inner liner corresponding to a tube; 13 is a rim;
4 is a hump which is a knob-shaped projection that acts to prevent the bead D of the tire from slipping off the bead seat, and is particularly effective when the air from the tire is released. The tire 1 shown as the illustrated embodiment is an example of a configuration that can exhibit the most suitable tire characteristics as a run-flat tire when used as the front wheel of a 750 c.c. or 1000 c.c. class motorcycle, which is a large vehicle. This is what is shown. The carcass 2 of the tire 1 is composed of four plies 3, and has a bias structure in which the cords of each ply 3 intersect with each other, and the cord angle of the carcass ply (crossing angle with the circumferential center line of the tire) is approximately 32 The carcass 2, which is directed from the tread section A to the bead section D, is folded back and rolled up from the inside of the tire to the outside at the bead wire 11, and the end of each ply 3 ends at the side section C with a step. The material of this carcass cord can be any tire cord such as nylon, rayon, polyester, steel, etc., but in this example, rayon cord (1100D/2) was used.
Then, between the carcass 2 extending from the tread part A to the bead part D of the tire and the folded carcass 2' rolled up with the bead wire 11 as a boundary, side reinforcement is provided that extends continuously from the bead wire 11 to the shoulder part B to the tread part. Layer 7 is placed. As shown in FIGS. 2 and 3, this side reinforcing layer 7 is a combination of a rubber filler 8 and plies 9, 9', in which the filler 8 is sandwiched between the plies 9, 9', and the tread of the filler 8 is The side edges of the section are completely covered with plies 9, 9', and further plies 9, 9'.
9' remains aligned for a certain length and ends. Furthermore, the cords of ply 9 and ply 9' are configured to cross each other to balance the stress applied to the side portions. and side reinforcement ply 9,9'
In the relationship between plies 9 and carcass 2, it is better to make the cord angles of plies 9 and 9' the same as the cord angles of carcass plies (in the same direction angle), rather than making them the same as the cord angles of carcass plies. This is advantageous for improving durability and tire motion characteristics (cornering performance, straight-line stability, etc.) by considering stress distribution in the sidewall bending state. In other words, uneven resistance to bending motion applied to the sidewalls causes abnormal deformation of the tire sidewalls, reduces runflat durability of the tire, inhibits straight-line stability during runflats, and causes steering wheel shake. Become. Therefore, as a result of various considerations,
It has been found that it is better to give the cord angle of the side reinforcing ply a larger angle than the carcass cord angle.
The cord for ply 9 can be selected from nylon, rayon, polyester, steel, etc. cords used in tires, depending on the tire size and required characteristics, but in this example, rayon cord (1650D/2) was used. The cord angle was set at 50 degrees with respect to the tire equator. Further, the hardness of the rubber filler 8 to be combined has an important meaning when acting as a load support, and must be determined according to the tire size and required dynamic characteristics of the tire. In this example, a hard rubber with a JIS rubber hardness of 75 degrees was used (although this is related to the crack resistance of the rubber, higher hardness is generally better). The reason why the rubber filler 8 and the plies 9, 9' are combined in the side reinforcing layer 7 is that, for example, it is possible to obtain a certain degree of effect by reinforcing only the rubber filler 8. In other words, it is necessary to make the rubber filler thick enough to resist the stress, or to increase the hardness of the rubber, but since it is a two-wheeled vehicle, it is difficult to satisfy the required high-speed and advanced motion characteristics,
Rubber's fatigue resistance is insufficient to satisfy runflat characteristics for running distances of 100 km or more at km/h. Therefore, the combination of the rubber filler and the reinforcing cord can exhibit the characteristics of both while increasing the volume, weight, etc. to the minimum necessary extent. This also has the advantage that the properties of the tire in the inflated state do not deteriorate significantly compared to ordinary tubeless tires. Regarding the relationship between rubber filler and reinforcing ply,
The bead part D side has bead wire and carcass 2, 2'
Since it has sufficient rigidity, there is no particular problem.Since it is necessary to have an effective reinforcing layer from the shoulder part B to the tread part A, the rubber filler in that part is structured so that the reinforcing ply is bent and wrapped. This significantly improves rigidity and is the most effective method, but it requires a complicated work process, reduces processing efficiency, or requires more expensive manufacturing equipment, resulting in a significant increase in manufacturing costs. I end up. The configuration of the rubber filler and reinforcing ply that can suppress increases in processing efficiency and manufacturing costs without significantly reducing the effectiveness of the reinforcing ply is as follows. In other words, the conventional folding structure, which is effective but expensive to manufacture, is made by overlapping the side reinforcing ply from the bending point and extending it a certain dimension toward the tread center without intervening a rubber filler in the overlapped part. By making use of the terminal effect of the reinforcing ply, the various functions of the tire can be achieved almost equally, and by eliminating the bending structure, the carcass 2 can be formed using conventional tire forming equipment as is. By forming the bead wire 11, then the reinforcing ply 9, then the rubber filler 8, then the reinforcing ply 9', and then winding up the carcass 2', the number of man-hours increases as the number of parts increases.
Since tires can now be molded using conventional methods, manufacturing costs can be significantly lower than for runflat tires with side reinforcing layers in a folded configuration. The cord used in the breaker 6 shown in FIG. 1 can be selected from nylon, rayon, polyester, steel, etc. according to the size of the tire, the usage conditions of the tire, and the required characteristics. Rayon cord (1650D/2)
and set the cord angle to 40 to the tire equator line.
It consists of two plies that intersect with each other. The reason for the existence of this breaker 6 is that when a camber angle is set on the tire with zero air pressure,
In other words, when the contact area with the road surface moves closer to the shoulder area B, a large bending stress is applied not only to the tire side area C but also to the tread area A. At this time, if the resistance to the bending stress at the tread area is small, cornering performance will be reduced. This is to prevent this from occurring, as this can cause instability when driving around curves. For the above reasons, it is recommended to use it on vehicles with a small tire load and a small tire cross-sectional shape (lower bending moment), for example, with a displacement of 50 to 100 c.c.
Breaker 6 is not necessary for tires with a size of 2.75-17. Although the side reinforcing layer, breaker, carcass, chief, etc. have been explained in cross section, it goes without saying that they are continuous in the tire circumferential direction. In addition to adopting the above tire configuration,
When the tire is assembled with the rim, the bead of the tire is held firmly against the rim.
A hump is provided on the rim as shown in the above example as a necessary condition for forming a run-flat tire with higher performance, and as a means to prevent the bead of the tire from coming off the rim seat. In addition, the air pressure for fitting the tire to the rim is 3Kg/cm ²
It was found that it is effective to take the bead tightness so that the above is achieved. However, even if the tightness is increased, if the fitting pressure reaches 7 to 10 kg/ ^cm2 , it will become difficult to assemble the rim and become impractical, so the rim fitting pressure should be 3 to 4 kg/cm2. It is better to set it to ² . Of course, the method of holding the bead portion on the rim seat will be more secure if it is fixed with adhesive or physically using a stopper or stopper ring. Next, as shown in Table 1, according to the characteristic evaluation during run-flat running of tires with various specifications for side reinforcing layers, the tire with specification (C) had the best results. This is followed by the (A) specification of the present invention. The above ranking was obtained in terms of properties during runflat running, but on the other hand, from the viewpoint of tire productivity, the (A) specification tire of the present invention has more than twice the productivity of the (C) specification tire. Therefore, even when considering both run-flat running evaluation and productivity, the (A) specification tire of the present invention has an advantage as a run-flat tire and has sufficient performance.

[Table] Furthermore, when considering the durability of the (A) specification tire, it shows sufficient performance as a run-flat tire as shown below. Tire: 350H19-4PR 1st stage; Air pressure: 0Kg/cm ² Load: 206Kg (Standard load according to JIS is 234Kg
However, since the running surface is a drum, the load corresponding to the radius of curvature of the drum was subtracted. ) After one hour (90 km) of run-flat driving at a speed of 90 km/h, no abnormalities were found in the tires. 2nd stage: Continuing, Air pressure: 2.8Kg/cm ² Load: 206Kg Speed: Started at 120Km/h, increased the speed by 8Km/h every 30 minutes, and ran for 15 minutes at a speed of 209Km/h. There was a problem with the tire tread flying off, so we stopped the race. Also, even tires with specification (B) are small in size (2.75−
17) showed sufficient performance, so when the size of the tire is limited, i.e., compared to tires for 1000 c.c. displacement, small size tires used for vehicles with displacement of about 100 c.c. ( B) If the specifications are applied, it will be fully effective as a run-flat tire. As explained above, according to the present invention, the top part of the tread part side of the elastic filler is sandwiched from the left and right sides from the bead part to the shoulder part and the tread part of a runflat tire for two-wheeled vehicles with reinforcing ply,
In addition, by providing a side reinforcing layer in which the reinforcing plies are overlapped and extended by a certain distance toward the tread center to achieve an effect almost equivalent to bending and wrapping, the side part of the tire,
In particular, it is possible to achieve a sufficient side reinforcement effect without increasing the thickness of the upper part (tread part side) more than necessary, and without significantly increasing the manufacturing cost. Since the reinforcement can be well-balanced, the tire will not completely collapse when filled with air, or even when the air is completely deflated, maintaining straight-line performance, cornering performance, and durability, which are important for motorcycles. Enough space is provided to enable safe run-flat driving. Therefore, even if you suddenly get a flat tire while driving at high speed, you can maintain control of the vehicle, and if you reduce the speed to a certain extent, you can run flat to the service area without changing the speed. Since the structure is basically the same as that of a tire, a simple repair will allow you to drive as before the puncture. Furthermore, the side reinforcing layer of the present invention has an integral structure of an elastic filler and a reinforcing ply, and has a structure that eliminates extra labor during tire molding as much as possible, so there is no difficulty in manufacturing the tire, and moreover, only an integral structure can be used. sufficient reinforcement of the entire side part can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of one embodiment of a runflat tire for two-wheeled vehicles according to the present invention, and FIG.
FIG. 3 is an enlarged sectional view showing details of the side portion in the figure, and FIG. 3 is a developed view of a part of the side reinforcing layer. 1... Tire, 2... Carcass, 2'... Turned part of carcass, 3... Ply, 4... Treaded rubber, 5... Side rubber, 6... Breaker, 7
...Side reinforcement layer, 8...Rubber filler, 9,
9'...Reinforcement ply, 10...Chef fur, 1
1...Bead wire, 12...Inner liner, 13...Rim, 14...Hump, A...Tread portion, B...Shoulder part, C...Side part,
D...Bead part.

Claims (1)

[Scope of Claims] 1. A runflat for a two-wheeled vehicle, which comprises a dredged portion, a pair of left and right bead portions, and a pair of side portions that connect the tread portion and the bead portion, and whose carcass cord has a bias structure. A runflat for a two-wheeled vehicle in a tire, characterized in that a side reinforcing layer is provided from the bead part to the tread part over the shoulder part and sandwiching the top part of the elastic filler on the tread part side between at least two reinforcing plies. tire. 2. Claim 1, characterized in that the side reinforcing layer is sandwiched between the folded part of the carcass folded back at the bead core and the inner carcass.
A run-flat tire for two-wheeled vehicles as described in Section 1. 3. A runflat tire for a two-wheeled vehicle according to claim 1 or 2, characterized in that the two reinforcing plies in the side reinforcing layer intersect with each other. 4. A runflat tire for a two-wheeled vehicle according to claim 1, 2, or 3, wherein the end of the side reinforcing layer on the bead side extends to a position where it contacts the bead wire. 5 Claim 1, characterized in that the tread portion has a breaker layer between it and the carcass.
The runflat tire for two-wheeled vehicles according to item 1, 2, 3, or 4. 6. Claims 1, 2, and 3, characterized in that the angle that the cords of the reinforcing ply in the side reinforcing layer make with the tire circumferential direction is larger than the angle that the carcass cord makes with the tire circumferential direction. Fourth
The runflat tire for two-wheeled vehicles as described in item 1 or 5.