Vehicle pneumatic tires with asymmetric carcass

Abstract

Vehicle pneumatic tire with at least one profiled tread (1), a belt (2), two sidewalls (8), two bead cores (6) and a carcass (3) which extends from one bead core (6) to the other bead core (6) and encloses them, wherein the carcass (3) has at least one carcass ply (31, 32), wherein each carcass ply (31, 32) is closed in the circumferential direction and has reinforcing elements (9) which are arranged substantially parallel to each other within the carcass ply (31, 32) and are embedded in elastomeric material (14), and each carcass ply (31, 32) has at least one overlap connection (10) which extends between the two edges of the carcass ply (31, 32), characterized in that • the carcass (3) is made in two layers, • that the carcass (3) has exactly three non-overlapping carcass ply sections (21, 22, 23), each of which extends at least from the radially outer height of a bead core (6a) in a radial direction (rR) towards the belt (2) and is led to below the belt (2) and each of which is closed in the circumferential direction, • that the carcass (3) on the outer half (Fa) of the tire which is intended to face the outside of the vehicle when mounted on the vehicle has the first carcass ply section (21) and the second carcass ply section (22) of the three carcass ply sections (21, 22, 23), wherein the first carcass ply section (21) is arranged axially within the second carcass ply section (22), • that the carcass (3) on the inner half (Fi) of the tire which is intended to face the inside of the vehicle when mounted on the vehicle has the third carcass ply section (23) of the carcass (3), • that the first carcass ply (31) comprising the first carcass ply section (21) and the third carcass ply section (23) runs around each bead core (6) from axially inside to axially outside and each ends in a carcass high point (3a) radially within the height (P) of the maximum axial extension of the tire, • that the outer half of the tire (Fa), which is intended to face the outside of the vehicle when mounted on the vehicle, has the second carcass layer (32) and • that the second carcass layer (31) is arranged axially outside the first carcass layer (31) at the height (P) of the maximum axial extension of the tire and is led radially from the radially outer height of the bead core (6a) to below the belt (2), including the second carcass layer section (22).

Description

[0001] The invention relates to a pneumatic vehicle tire with at least one profiled tread, a belt, two sidewalls, two bead cores and a carcass which extends from one bead core to the other bead core and wraps around them, wherein the carcass has at least one carcass ply, wherein each carcass ply is closed in the circumferential direction and has strength members which are arranged substantially parallel to one another within the carcass ply and are embedded in elastomeric material, and each carcass ply has at least one overlap connection which extends between the two edges of the carcass ply.

[0002] A pneumatic vehicle tire generally has an air-impermeable inner layer, a carcass containing reinforcements, which extends from the crown area of ​​the tire over the sidewalls to the bead areas and is usually anchored there by wrapping tensile bead cores, a profiled tread located radially outward and a belt arranged between the tread and the carcass, which usually contains at least two reinforcement layers and is covered radially outward with the belt bandage.

[0003] The reinforcements in the carcass contain the tire's internal pressure and keep the tire in shape. During the manufacturing process of a carcass ply as a semi-finished product or when closing the carcass ply after being laid on the building drum, parts of the carcass ply are usually joined together using an overlap joint. On the finished tire, such an overlap joint extends from one axial edge to the other axial edge and is generally parallel to the direction of extension of the reinforcements. If both parts contain reinforcements in the area of ​​the overlap joint, this leads to a local increase in the reinforcement density. This leads to an increase in the strength of the carcass ply in the direction of extension of the reinforcements in the overlap area. This causes a necking of the tire, particularly in the sidewall area.If this constriction is so pronounced that it is visible to an observer, the perceived quality of the tire may be reduced.

[0004] It is common practice to construct the carcass with two solid plies. This increases the carcass' stiffness and reduces the effect of constriction, thus creating a higher-quality impression of the tire. However, such a second ply requires considerable additional material, which negatively impacts the tire's material costs, weight, and rolling resistance.

[0005] DE 1680453 A discloses a pneumatic vehicle tire with an asymmetric single-ply radial carcass. DE 102007019717 A1 and US 6267166 B1 each disclose a two-ply carcass with an asymmetric structure, with each of the carcass plies wrapping around exactly one bead core.

[0006] It is the object of the invention to provide a pneumatic vehicle tire which also creates a high quality impression for an observer and is more cost-effective to manufacture and has improved rolling resistance.

[0007] The problem is solved in that the carcass has exactly three non-overlapping carcass ply sections, each of which runs from the radially outer height of a bead core in the radial direction towards the belt and is guided under the belt and which are each closed in the circumferential direction, in that the carcass has the first carcass ply section and the second carcass ply section of the three carcass ply sections on the outer half of the tire which, when mounted on the vehicle, faces the outside of the vehicle, wherein the first carcass ply section is arranged axially inside the second carcass ply section, and in that the carcass has the third carcass ply section of the carcass on the inner half of the tire which, when mounted on the vehicle, faces the inside of the vehicle.

[0008] The terms "inside the vehicle" and "outside the vehicle" refer to the cross-sectional halves of the tire and are intended to describe the orientation of the tire in the operating state when the tire is mounted on the vehicle. "Carcass ply sections" are subsections of carcass plies. If a carcass ply contains several carcass ply sections, they are spaced apart from each other and do not overlap. Heights are measured from the radially inner end of the bead core. The "radial outer height of a bead core" is the height of the radially outer end of the bead core.

[0009] The vehicle's outer sidewall has exactly two carcass ply sections, namely the first and second carcass ply sections, which each extend from the bead core arranged on the tire's outer half to below the belt. Towards the belt, the carcass ply sections thus extend below the edge region of the belt arranged on the tire's outer half, i.e., they extend axially within the axial end of the belt arranged on the tire's outer half. The first carcass ply section is arranged axially within the second carcass ply section. The first carcass ply section can be part of the same carcass ply or part of a different carcass ply than the second carcass ply section.

[0010] The inner sidewall, on the other hand, has only one carcass ply section, namely the third. This increases the stiffness of the tire's outer half compared to the inner half. Therefore, constriction of the sidewall caused by an overlap joint is greater on the non-visible inner half of the tire than on the visible outer half of the tire when mounted.

[0011] The material-intensive measure to improve the perceived quality by reducing sidewall constriction by increasing carcass stiffness is therefore only implemented on the outer side of the tire mounted on the vehicle, which is visible to the observer. The invisible inner side of the tire mounted on the vehicle, on the other hand, has only one carcass ply section, which is selected to adequately ensure the durability and driving characteristics of the pneumatic vehicle tire. Each carcass ply section is guided from the radially outer height of the bead cores to below the belt, thus extending in the belt area to axially within the belt edge. This ensures that the carcass is stiffened on the outer half of the tire and that the carcass' durability is ensured for the entire extent between the bead core and the belt.

[0012] This provides a pneumatic vehicle tire that has a high quality appearance when mounted on the vehicle and is more cost-effective to manufacture due to the use of less material and also has improved rolling resistance due to the weight savings.

[0013] In an embodiment not according to the invention, the carcass is designed as a single ply, wherein the carcass ply of the carcass runs around each bead core from axially inside to axially outside and ends in a carcass turnup in each case, and the carcass turnup arranged on the outer half of the tire facing the outside of the vehicle, including the second carcass ply section, is led under the belt. The carcass turnup of exactly one carcass ply arranged on the inner half of the tire therefore extends less far radially outwards than the carcass turnup of exactly one carcass ply arranged on the outer half of the tire. The carcass turnup on the inner half of the tire is therefore not led under the belt, it preferably ends radially within the height of the maximum axial extent of the tire, i.e. radially within the height at which the tire has its maximum axial extent.With a simple design and reduced use of materials, this provides a tire that has a minimal constriction of the visible sidewall of the tire mounted on the vehicle.

[0014] According to the invention, the carcass is designed in two layers, wherein the first carcass ply, comprising the first carcass ply section and the third carcass ply section, runs around each bead core from axially inside to axially outside and each ends in a carcass turn-up radially within the height of the maximum axial extent of the tire, wherein the outer half of the tire facing the outside of the vehicle has the second carcass ply, wherein the second carcass ply is arranged axially outside the first carcass ply at the height of the maximum axial extent of the tire and, comprising the second carcass ply section, is guided in the radial direction from the radially outer height of the bead core to below the belt. The first carcass ply is thus a so-called full carcass ply. The bundling of the forces occurring during tire operation and the structural durability of the tire are primarily ensured by the first carcass ply.The second carcass ply is positioned axially outside the first carcass ply in the upper area of ​​the tire's outer sidewall. This also results in a tire with a simple design and reduced material usage that exhibits minimal constriction of the visible sidewall of the tire mounted on the vehicle, creating a high-quality impression.

[0015] Preferably, on the outer half of the tire facing the outside of the vehicle, the second carcass ply section of the second carcass ply runs in the region of the carcass turnup of the first carcass ply axially outside the carcass turnup of the first carcass ply.

[0016] It is also preferred if, on the outer half of the tire facing the vehicle exterior, the second carcass ply section of the second carcass ply extends axially within the carcass turnup of the first carcass ply in the region of the carcass turnup of the first carcass ply. In this case, the second carcass ply can extend axially inside or outside the bead core and end there and / or at least partially wrap around the bead core.

[0017] It is advantageous if the reinforcements of the first carcass ply and the reinforcements of the second carcass ply are made of the same material. The reinforcements of both carcass plies thus have the same material properties.

[0018] It is advisable if all reinforcements in a carcass ply are of the same design.

[0019] In a preferred embodiment, the product EF1 of the average modulus of elasticity of the strength members of the first carcass ply and the thread density of the strength members of the first carcass ply and the product EF2 of the average modulus of elasticity of the strength members of the second carcass ply and the thread density of the strength members of the second carcass ply satisfy the relationship EF1 > EF2, preferably the relationship 1.5 x EF2 ≥ EF1 ≥ 1.3 x EF2, wherein the modulus of elasticity of a strength member is measured at an elongation of 2% according to ASTM D885. The force that must be applied to the strength member at 2% elongation is determined. It is expedient if all strength members of a carcass ply have the same modulus of elasticity.However, if a carcass ply contains reinforcements with different moduli of elasticity, the average modulus of elasticity of the reinforcements of the respective ply is determined using the arithmetic mean. The thread density indicates how many reinforcements are arranged perpendicular to the extension of the reinforcements per unit length. The products EF1 and EF2 thus correspond to the cumulative modulus of elasticity of the reinforcements arranged per unit length (the thread density) and thus determine the extensibility of the reinforcements arranged in relation to the reinforcement layer of the respective carcass ply. This extensibility of the reinforcement layer, in turn, serves as an indicator of the extensibility of the respective carcass ply containing such a reinforcement layer.It has been shown that a second carcass ply with a reduced product of elastic modulus and thread density of the reinforcements compared to the first carcass ply sufficiently ensures the tire's robustness and reduces sidewall constriction compared to a single-ply carcass. Such a second carcass ply is also characterized by reduced material costs.

[0020] In a further preferred embodiment, the product FF1 of the average fineness of the reinforcements of the first carcass ply and the thread density of the reinforcements of the first carcass ply and the product FF2 of the average fineness of the reinforcements of the second carcass ply and the thread density of the reinforcements of the second carcass ply satisfy the relationship FF1 > FF2, preferably the relationship 1.5 x FF2 ≥ FF1 ≥ 1.3 x FF2. The fineness is a measure of the weight of the reinforcement per length of the reinforcement. It is expedient if all reinforcements of a carcass ply have the same fineness. However, if a carcass ply has reinforcements with different finenesses, the average fineness of the reinforcements of the respective ply is determined according to the arithmetic mean.If a carcass ply contains reinforcements of different thicknesses, the average thickness of the reinforcements of the respective ply is used to determine the product. Such a combination of carcass plies provides a simple way to reduce material usage while maintaining sufficient robustness of the pneumatic vehicle tire.

[0021] A particularly simple design is achieved when all reinforcements in a carcass ply are of the same design. A particularly simple design is also achieved when the two carcass plies differ only in the fineness of the reinforcements, the thread density of the reinforcements, or the elastic modulus of the reinforcements.

[0022] In a preferred embodiment, the reinforcement members of the two carcass ply sections arranged on the outer half of the tire facing the vehicle exterior, with opposite pitch directions, form an approximately equal angle of 85° to 90° with the circumferential direction of the pneumatic vehicle tire. This particularly effectively reduces sidewall constriction caused by the overlap connection of one ply by the other ply.

[0023] It is advisable for exactly one carcass ply to end below the belt. Either the carcass turnup of the single carcass ply, which contains the second carcass ply section, ends below the belt, or the second carcass ply of a two-ply carcass ends below the belt. This significantly reduces the tire's weight and reduces its manufacturing costs without compromising durability.

[0024] Such a tire is ideal as a tire for passenger cars and commercial vehicles, especially for cars.

[0025] Further features, advantages, and details of the invention will now be explained in more detail with reference to the drawings, which illustrate schematic embodiments. They show: Fig. 1 a cross-section through a car tire; Fig. 2 a cross-section through an overlap joint of a carcass ply of a passenger car tire according to the invention; Fig. 3 a cross-section through a non-inventive example of the carcass arrangement in a passenger car tire; Fig. 4 to Fig. 6 each shows a cross section through an embodiment of the carcass arrangement according to the invention in a passenger car tire.

[0026] In the Fig. Figure 1 shows a schematic cross-section through a pneumatic car tire. The left half of the drawing represents the inner tire half Fi and the right half of the drawing represents the outer tire half Fa visible to an observer. The essential components of the tire shown are a profiled tread 1, a belt 2, which is covered radially on the outside by a belt bandage 13, a largely airtight inner layer 4, beads 5 with bead cores 6 and bead core profiles 7 as well as sidewalls 8 and a carcass 3, which extends from one bead core 6 to the other bead core 6 and wraps around them. The carcass 3 is designed as a single-ply or a double-ply, with the carcass ply(s) in the Fig. 1 is (are) not shown individually. The belt 2 has two plies (not shown in detail), which, in a known manner, consist of reinforcements made of steel cord embedded in a rubber mixture, which extend parallel to one another within each ply. The steel cords of one ply are oriented in a crossing arrangement with the steel cords of the second ply. The carcass 3 also has reinforcements made of a textile material or steel cord embedded in elastomeric material, which extend in the radial direction and are arranged essentially parallel to one another within each carcass ply, and wherein each carcass ply is closed in the circumferential direction of the pneumatic vehicle tire.

[0027] The Fig. Figure 2 shows a cross section through a section of a carcass ply 31 of the Fig. 1, which has an overlap joint 10. The cross-section runs perpendicular to the direction of extension of the strength members 9, which are arranged essentially parallel to one another and embedded in elastomeric material 14. Two parts 11, 12 of the carcass ply 31 are joined together by an overlap joint 10 during the manufacturing process of the carcass ply 31 as a semi-finished product or when closing the carcass ply 31 after being laid on the building drum. On the tire, the overlap joint 10 extends from one (axial) edge of the carcass ply to the other (axial) edge of the carcass ply. Both parts 11, 12 contain strength members 9 in the area of ​​the overlap joint 10, which leads to a local increase in the strength of the carcass ply 31, which causes a constriction of the surface in the area of ​​the sidewall 8 of the tire.

[0028] The Fig. 3 to Fig. 6 each show a cross-section through an embodiment of the carcass ply arrangement in a passenger car tire. The carcass ply arrangements shown are suitable for the Fig. 1 car tires shown.

[0029] In the Fig. 3 to Fig. 6, the carcass 3 includes exactly three non-overlapping carcass ply sections 21, 22, 23, each of which extends from the radially outer height 6a of a bead core 6 in the radial direction rR toward the belt 2 and extends below the belt 2 and is closed in the circumferential direction of the tire. The height 6a and the height P are measured from the radially inner end of the bead core 6.

[0030] The carcass 3 has, on the outer tire half Fa, which faces the outside of the vehicle when mounted on the vehicle, the first carcass ply section 21 and the second carcass ply section 22 of the three carcass ply sections 21, 22, 23, wherein the first carcass ply section 21 is arranged axially inside the second carcass ply section 22. Furthermore, the carcass 3 has, on the inner tire half Fi, which faces the inside of the vehicle when mounted on the vehicle.

[0031] The reinforcement members 9 of the two carcass ply sections 21, 22 arranged on the outer half of the tire Fa enclose an approximately equal angle of 85° to 90° with the circumferential direction of the pneumatic vehicle tire when the pitch direction is opposite.

[0032] The Fig. 3 shows a non-inventive example of a carcass arrangement in which the carcass 3 has exactly one carcass ply 31, wherein the carcass ply 31 includes all three carcass ply sections 21, 22, 23. The carcass ply 31 runs around each bead core 6 from axially inside to axially outside and ends in a carcass turnup 3a. On the tire outer half Fa, this carcass turnup 3a includes the carcass ply section 22. The carcass turnup 3a is thus guided on the tire outer half Fa down to below the belt 2 and ends axially within the axial end of the belt arranged on the tire outer half Fa. The carcass turnup 3a on the tire inner half Fi, on the other hand, is not guided down to below the belt 2 but ends radially within the height P of the maximum axial extension of the tire.

[0033] The Fig. 4 to Fig. 6 each show an exemplary embodiment of a carcass arrangement according to the invention with a two-ply carcass 3. The first carcass ply 31 runs around each bead core 6 from axially inside to axially outside and ends in a carcass turnup 3a radially inside the height P of the maximum axial extent of the tire. The first carcass ply 31 includes the first carcass ply section 21 and the third carcass ply section 23. The second carcass ply 32 is arranged on the tire outer half Fa and is arranged axially outside the first carcass ply 31 at the height P of the maximum axial extent of the tire. The second carcass ply 32 includes the second carcass ply section 22, which is guided at least from the radially outer height 6a of the bead core 6 in the radial direction rR and up to below the belt 2. The reinforcement members 9 of the first carcass ply 31 and the reinforcement members 9 of the second carcass ply 31 are made of the same material.Within each carcass ply 31, 32, the reinforcement members 9 are of identical design and arranged with a constant thread spacing. All reinforcement members 9 of the first carcass ply 31 are of identical design. All reinforcement members 9 of the second carcass ply 32 are also of identical design.

[0034] The Fig. 4 shows an embodiment in which, on the tire outer half Fa, the second carcass ply section 21 of the second carcass ply 32 extends axially outside the carcass turnup 3a of the first carcass ply 31 in the region of the carcass turnup 3a of the first carcass ply 31. The second carcass ply 32 is not guided around the bead core 6. The product EF1 of the average elastic modulus of the strength members of the first carcass ply 31 and the thread density of the strength members of the first carcass ply 31 and the product EF2 of the average elastic modulus of the strength members of the second carcass ply 32 and thread density of the strength members of the second carcass ply 32 satisfy the relation 1.5 × EF2 ≥ EF1 ≥ 1.3 × EF2, wherein the elastic modulus of a strength member is measured at an elongation of 2% according to ASTM D885.Furthermore, the product FF1 of the average fineness of the reinforcements of the first carcass ply 31 and the thread density of the reinforcements of the first carcass ply 31 and the product FF2 of the average fineness of the reinforcements 9 of the second carcass ply 32 and the thread density of the reinforcements 9 of the second carcass ply 32 satisfy the relation 1.5 × FF2 ≥ FF1 ≥ 1.3 × FF2.

[0035] The Fig. 5 shows an embodiment in which, on the tire outer half Fa, the second carcass ply section 21 of the second carcass ply 32 extends axially within the carcass turnup 3a of the first carcass ply 31 in the region of the carcass turnup 3a of the first carcass ply 31. It extends axially between the bead core profile 7 and the first carcass ply section 21 of the first carcass ply 31. The reinforcement members 9 of both carcass plies 31, 32 are made of polyester. The product EF1 and the product EF2 approximately satisfy the relationship EF1 = 1.4 × EF2. Furthermore, the product FF1 and the product FF2 satisfy the relationship 1.5 × FF2 ≥ FF1 ≥ 1.3 × FF2. The reinforcement members of the first carcass ply 31 form an angle of approximately 89° with the circumferential direction of the pneumatic vehicle tire at opposite pitch angles.

[0036] The Fig.6 shows a further embodiment in which, on the tire outer half Fa, the second carcass ply section 21 of the second carcass ply 32 extends axially within the carcass turnup 3a of the first carcass ply 31 in the region of the carcass turnup 3a of the first carcass ply 31. Coming from the belt 2, it extends axially between the bead core profile 7 and the carcass ply section 21 of the first carcass ply 31, is guided around the bead core 6, and ends axially between the bead core profile 7 and the carcass turnup 3a of the first carcass ply 31.

[0037] The reinforcements of the first carcass ply 31 and the reinforcements of the second carcass ply 32 are made of polyester. The reinforcements of the first carcass ply 31 are cords made of two end-twisted yarns of 1440 dtex, arranged with a thread density of 105 epdm. The reinforcements of the second carcass ply 32 are cords made of two end-twisted yarns of 1100 dtex, arranged with a thread density of 100 epdm. The reinforcements of the two carcass plies 31, 32 form an approximately equal angle of approximately 86° with the tire's circumferential direction, with opposite pitch directions. List of reference symbols 1 tread 2 belts 3 Carcass 3a Carcass roll-up 4 inner layer 5 bulge 6 Bead core 6a radial outer height of the bead core 7 Bead core profile 8 Side wall 9 Strength members 10 Overlap joint 11,12 Part of the carcass ply 13 Belt bandage 14 elastomeric material 21,22,23 Carcass ply section 31,32 Carcass ply Fi vehicle interiors Fa vehicle exterior P Height of the maximum axial extension of the tire rR radial direction aR axial direction

Claims

[1] A pneumatic vehicle tire having at least one profiled tread (1), a belt (2), two sidewalls (8), two bead cores (6) and a carcass (3) extending from one bead core (6) to the other bead core (6) and wrapping around them, wherein the carcass (3) has at least one carcass ply (31, 32), wherein each carcass ply (31, 32) is closed in the circumferential direction and has reinforcement members (9) arranged substantially parallel to one another within the carcass ply (31, 32) and embedded in elastomeric material (14), and each carcass ply (31, 32) has at least one overlap joint (10) extending between the two edges of the carcass ply (31, 32), characterized by , that • the carcass (3) is made of two layers, • that the carcass (3) has exactly three non-overlapping carcass ply sections (21, 22, 23), which each run at least from the radially outer height of a bead core (6a) in the radial direction (rR) towards the belt (2) and are guided under the belt (2) and which are each closed in the circumferential direction, • that the carcass (3) on that outer half of the tyre (Fa) which is intended to face the outside of the vehicle when mounted on the vehicle has the first carcass ply section (21) and the second carcass ply section (22) of the three carcass ply sections (21, 22, 23), the first carcass ply section (21) being arranged axially inside the second carcass ply section (22), • that the carcass (3) has the third carcass ply section (23) of the carcass (3) on that inner half of the tyre (Fi) which is intended to face the vehicle interior when mounted on the vehicle, • that the first carcass ply (31), including the first carcass ply section (21) and the third carcass ply section (23), extends around each bead core (6) from axially inside to axially outside and ends in a carcass turn-up (3a) radially inside the height (P) of the maximum axial extension of the tire, • that the outer half of the tyre (Fa), which is intended to face the outside of the vehicle when mounted on the vehicle, has the second carcass ply (32) and • that the second carcass ply (31) is arranged at the height (P) of the maximum axial extension of the tire axially outside the first carcass ply (31) and, including the second carcass ply section (22), is guided from the radially outer height of the bead core (6a) in the radial direction to under the belt (2). [2] Pneumatic vehicle tyre according to claim 1, characterized bythat on the outer half of the tyre (Fa), which in the state mounted on the vehicle is intended to point towards the outside of the vehicle, the second carcass ply section (22) runs in the region of the carcass turn-up (3a) of the first carcass ply (31) axially outside the carcass turn-up (3a) of the first carcass ply (31). [3] Pneumatic vehicle tyre according to claim 1, characterized by that on the outer half of the tyre (Fa), which in the state mounted on the vehicle is intended to point towards the outside of the vehicle, the second carcass ply section (22) runs in the region of the carcass turn-up (3a) of the first carcass ply (31) axially within the carcass turn-up (3a) of the first carcass ply (31). [4] Pneumatic vehicle tyre according to one or more of claims 1 to 3, characterized by that the strength members (9) of the first carcass ply (31) and the strength members (9) of the second carcass ply (32) are made of the same material. [5] Pneumatic vehicle tyre according to one or more of claims 1 to 4, characterized by that the product EF1 of the average modulus of elasticity of the strength members (9) of the first carcass ply (31) and the thread density of the strength members (9) of the first carcass ply (31) and the product EF2 of the average modulus of elasticity of the strength members (9) of the second carcass ply (32) and the thread density of the strength members (9) of the second carcass ply (32) satisfy the relation EF1 > EF2, preferably the relation 1.5 × EF2 ≥ EF1 ≥ 1.3 × EF2, wherein the modulus of elasticity of a strength member is in each case measured at an elongation of 2% according to ASTM D885. [6] Pneumatic vehicle tyre according to one or more of claims 1 to 5, characterized bythat the product FF1 of the average fineness of the strength members (9) of the first carcass ply (31) and the thread density of the strength members (9) of the first carcass ply (31) and the product FF2 of the average fineness of the strength members (9) of the second carcass ply (32) and the thread density of the strength members (9) of the second carcass ply (32) satisfy the relation FF1 > FF2, preferably the relation 1.5 × FF2 ≥ FF1 ≥ 1.3 × FF2. [7] Pneumatic vehicle tyre according to one or more of the preceding claims, characterized by that the reinforcement members (9) of the two carcass ply sections (21, 22) arranged on the outer half of the tyre (Fa), which, when mounted on the vehicle, is intended to point towards the outside of the vehicle, enclose an approximately equal angle of 70° to 90°, preferably an approximately equal angle of 85° to 90°, with the circumferential direction of the pneumatic vehicle tyre, with opposite pitch directions.

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