TIRE COMPRISING A SINGLE CARACSS PLY WITH AN IMPROVED DEFORMATION DEPTH IN THE SIDEWALL AFTER RUNNING IN

Abstract

A tire (10) comprises a crown (12) comprising a tread (20), a crown reinforcement (14), two sidewalls (22), two beads (24), with each sidewall (22) connecting each bead (24) to the crown (12), the crown reinforcement (14) extending into the crown (12). The tire (10) comprises a radial carcass reinforcement (32) anchored in each of the beads (24) and extending into the sidewalls (22), and the crown reinforcement (14) is radially inserted between the carcass reinforcement (32) and the tread (20). The tire (10) has a sidewall height that is greater than or equal to 110 mm and a load index that is greater than or equal to 94. The carcass reinforcement (32) comprises a single carcass ply (34) comprising at least one reinforcer element comprising an assembly formed by: a multifilament strand made of aromatic polyamide or aromatic co-polyamide; and a multifilament strand made of polyester.

Claims

1.-25. (canceled)

26. A tire comprising a crown comprising a tread and a crown reinforcement, two sidewalls, two beads, with each sidewall connecting each bead to the crown, the crown reinforcement extending into the crown in a circumferential direction of the tire, the tire comprising a radial carcass reinforcement anchored in each of the beads and extending into the sidewalls, the crown reinforcement being radially inserted between the carcass reinforcement and the tread, the tire having a sidewall height that is greater than or equal to 110 mm and a load index that is greater than or equal to 94, wherein the radial carcass reinforcement comprises a single carcass ply comprising at least one reinforcer element comprising an assembly formed by a plurality of multifilament strands comprising: at least one multifilament strand made of aromatic polyamide or aromatic co-polyamide; and at least one multifilament strand made of polyester.

27. The tire according to claim 26, wherein the sidewall height is greater than or equal to 120 mm.

28. The tire according to claim 26, wherein the sidewall height is less than or equal to 220 mm.

29. The tire according to claim 26, wherein the sidewall height ranges from 139 to 223 mm.

30. The tire according to claim 26, wherein the sidewall height is less than or equal to 141 mm.

31. The tire according to claim 26, wherein the load index is greater than or equal to 95.

32. The tire according to claim 26, wherein the load index is less than or equal to 130.

33. The tire according to claim 26, wherein a nominal inflation pressure is greater than or equal to 200 kPa.

34. The tire according to claim 26, wherein a nominal inflation pressure is less than or equal to 600 kPa.

35. The tire according to claim 26, wherein a nominal inflation pressure ranges from 425 kPa to 575 kPa.

36. The tire according to claim 26, wherein a nominal inflation pressure ranges from 175 kPa to 425 kPa.

37. The tire according to claim 26, wherein the tire has an aspect ratio ranging from 35 to 95.

38. The tire according to claim 26, wherein the tire has an aspect ratio ranging from 50 to 85.

39. The tire according to claim 26, wherein the tire has a nominal rim diameter ranging from 13 to 22 inches.

40. The tire according to claim 26, wherein the tire has a nominal rim diameter ranging from 14 to 20 inches.

41. The tire according to claim 26, wherein the tire has a nominal rim diameter ranging from 17 to 22 inches.

42. The tire according to claim 26, wherein the reinforcer element comprises an assembly formed by two multifilament strands.

43. The tire according to claim 42, wherein, with the two multifilament strands being helically wound around one another, the twist factor K of the reinforcer element ranges from 5.2 to 6.5, with K being defined by the formula K=(RTi.sup.1/2)/957, in which R is a twist of the reinforcer element expressed as revolutions per meter and Ti is a sum of the counts of the multifilament strands of the reinforcer element in tex.

44. A method for running-in a tire comprising the step of running-in the tire according to claim 26.

Description

[0103] The invention will be better understood in light of the following description, which is provided solely by way of a non-limiting example, and is provided with reference to the drawings, in which:

[0104] FIG. 1, previously described to explain the problem of sidewall deformations, is a section view of a carcass ply comprising reinforcer elements during the tyre manufacturing method, with the section being perpendicular to the reinforcer elements;

[0105] FIG. 2, previously described to explain the problem of sidewall deformations, is a view similar to that of FIG. 1 on completion of the tyre manufacturing method;

[0106] FIG. 3, previously described to explain the problem of sidewall deformations, is a force-extension curve of a reinforcer element of the carcass ply of FIGS. 1 and 2;

[0107] FIG. 4a is a radial section view of a tyre according to a first embodiment of the invention;

[0108] FIG. 4b is a radial section view of a tyre according to a second embodiment of the invention;

[0109] FIG. 5 illustrates a section view of a composite intended to form the carcass ply of each tyre of FIGS. 4a and 4b;

[0110] FIG. 6 illustrates a section view of the carcass ply of FIG. 5 along the V-V plane;

[0111] FIG. 7 is a schematic representation of the structure of the reinforcer elements of each carcass ply of each tyre of FIGS. 4a and 4b; and

[0112] FIG. 8 is an exploded section view of the reinforcer element of the carcass ply of the tyre of FIG. 4a.

[0113] A radial cross section or radial section is understood herein to be a cross section or a section in a plane that contains the axis of rotation of the tyre.

[0114] The median circumferential plane M of the tyre is the plane that is normal to the axis of rotation of the tyre and that is located equidistantly from the annular reinforcement structures of each bead.

[0115] The equatorial circumferential plane E of the tyre is the theoretical plane passing through the equator of the tyre, perpendicular to the median plane and to the radial direction. The equator of the tyre is, in a circumferential section plane (the plane perpendicular to the circumferential direction and parallel to the radial and axial directions), the axis parallel to the axis of rotation of the tyre and located equidistantly between the radially outermost point of the tread that is intended to be in contact with the ground and the radially innermost point of the tyre that is intended to be in contact with a support, for example, a rim, with the distance between these two points being equal to H.

[0116] An axial direction is a direction parallel to the axis of rotation of the tyre.

[0117] A circumferential direction is a direction that is perpendicular both to a radius of the tyre and to the axial direction.

[0118] In the present application, unless otherwise indicated, any interval of values designated by the term from a to b signifies the range of values ranging from the limit a to the limit b, i.e. including the strict limits a and b.

Tyre According to a First Embodiment of the Invention

[0119] FIG. 4a shows an X, Y, Z coordinate system corresponding to the common directions, respectively axial (X), radial (Y) and circumferential (Z), of a tyre.

[0120] Architecture of the Tyre

[0121] FIG. 4a schematically shows a radial section view of a tyre according to a first embodiment of the invention and designated using general reference sign 10. The tyre 10 substantially rotates about an axis substantially parallel to the axial direction X.

[0122] The sidewall height of the tyre 10 is greater than or equal to 110 mm, even greater than or equal to 120 mm, preferably greater than or equal to 130 mm, and even more preferably greater than or equal to 140 mm, and less than or equal to 220 mm, preferably less than or equal to 210 mm, and even more preferably less than or equal to 200 mm. The load index of the tyre 10 is greater than or equal to 94, even greater than or equal to 95, preferably greater than or equal to 97, and more preferably greater than or equal to 100, and less than or equal to 130, preferably less than or equal to 125, and more preferably less than or equal to 121. The nominal inflation pressure of the tyre 10 is greater than or equal to 200 kPa, preferably greater than or equal to 220 kPa, and more preferably greater than or equal to 250 kPa, and less than or equal to 600 kPa, preferably less than or equal to 585 kPa, and more preferably less than or equal to 575 kPa. The aspect ratio of the tyre 10 ranges from 35 to 95, and preferably from 40 to 80. The nominal rim diameter of the tyre 10 ranges from 13 to 22 inches, and preferably from 14 to 21 inches.

[0123] In this first embodiment, the tyre 10 in this case is intended for a light truck type vehicle and the size of said tyre is 215/75 R16 113/111R.

[0124] Thus, the sidewall height of the tyre 10 ranges from 139 to 223 mm, and preferably from 139 to 200 mm, and in this case is equal to 161 mm. The load index ranges from 100 to 125, and preferably from 102 to 121, and in this case is equal to 113/111. The nominal inflation pressure ranges from 425 kPa to 575 kPa, preferably from 450 kPa to 550 kPa, and more preferably from 475 kPa to 525 kPa, and in this case is equal to 475 kPa. The aspect ratio ranges from 50 to 85, preferably from 60 to 80, and more preferably from 65 to 75, and in this case is equal to 75. The nominal rim diameter ranges from 14 to 20 inches, preferably from 15 to 19 inches, and more preferably from 15 to 17 inches, and in this case is equal to 16 inches.

[0125] The tyre 10 comprises a crown 12 comprising a crown reinforcement 14 comprising a working reinforcement 15 comprising two working plies 16, 18 of working reinforcer elements and a hoop reinforcement 17 comprising a hoop ply 19 of hoop reinforcer elements. The crown reinforcement 14 extends into the crown 12 in the circumferential direction Z of the tyre 10. The crown 12 comprises a tread 20 radially arranged outside the crown reinforcement 14. In this case, the hoop reinforcement 17, in this case the hoop ply 19, is radially inserted between the working reinforcement 15 and the tread 20.

[0126] The tyre 10 also comprises two sidewalls 22 extending the crown 12 radially inwards. The tyre 10 further comprises two beads 24 radially inside the sidewalls 22 and each comprising an annular reinforcement structure 26, in this case a bead wire 28, overmounted by a bead gum mass 30 on the bead wire, as well as a radial carcass reinforcement 32. Each sidewall 22 connects each bead 24 to the crown 12.

[0127] The carcass reinforcement 32 comprises a carcass ply 34 comprising a plurality of reinforcer elements, the carcass ply 34 being anchored to each of the beads 24 by a turn-up around the bead wire 28, so as to form, in each bead 24, an outgoing strand 38 extending from the beads through the sidewalls towards the crown 12, and an incoming bead 40, the radially external end 42 of the incoming bead 40 being radially outside the annular reinforcement structure 26. The carcass reinforcement 32 thus extends from the beads 24 into and through the sidewalls 22 up to the crown 12. The carcass reinforcement 32 is radially arranged inside the crown reinforcement 14 and the hoop reinforcement 17. The crown reinforcement 14 therefore is radially inserted between the carcass reinforcement 32 and the tread 20. The carcass reinforcement 32 comprises a single carcass ply 34, which in this case is formed by the carcass ply 34.

[0128] The carcass reinforcement 32 is radial in each sidewall 22 and in the crown 12. Thus, each reinforcer element forms an angle ranging from 80 to 90 with the circumferential direction of the tyre 10 in the median M and equatorial E planes of the tyre 10.

[0129] The tyre 10 also comprises an internal sealing layer 46, preferably made of butyl, axially located inside the sidewalls 22 and radially located inside the crown reinforcement 14 and extending between the two beads 24.

[0130] Each working ply 16, 18, hoop ply 19 and carcass ply 34 comprises a polymeric composition, in which reinforcer elements of the corresponding ply are immersed. Each polymeric composition, in this case an elastomeric composition, of the working 16, 18, hoop 19 and carcass 34 plies is made from a conventional composition for calendering reinforcer elements conventionally comprising a diene elastomer, for example, natural rubber, a reinforcing filler, for example, carbon black and/or silica, a cross-linking system, for example, a vulcanization system, preferably comprising sulphur, stearic acid and zinc oxide, and optionally an accelerator and/or vulcanization inhibitor and/or various additives.

[0131] Carcass Ply of the Tyre 10

[0132] FIGS. 5 and 6 will now be referred to in order to describe a composite 50 intended to form the carcass ply 34 of the tyre 10.

[0133] The composite 50 comprises a plurality of reinforcer elements 44. The reinforcer elements 44 are arranged side-by-side parallel to each other in a main direction D substantially perpendicular to the general direction G along which the reinforcer elements of the composite 50 extend, with the general direction G forming, once the composite 50 forming the carcass ply 34 is inside the tyre 10, an angle ranging from 80 to 90 with the circumferential direction Z of the tyre 10. In this case, the general direction G forms, once the composite 50 forming the carcass ply 34 is inside the tyre 10, an angle substantially equal to 90 with the circumferential direction Z of the tyre 10.

[0134] The density of reinforcer elements 44 in the composite 50 ranges from 90 to 130 reinforcer elements per decimetre of composite 50, preferably from 100 to 125 reinforcer elements per decimetre of composite 50, more preferably from 105 to 120 reinforcer elements per decimetre of composite 50, and in this case is equal to 110 reinforcer elements per decimetre of composite 50.

[0135] The thickness Th of the composite 50 is less than or equal to 1.45 mm, and preferably less than or equal to 1.30 mm, and in this case is equal to 1.28 mm.

[0136] The density of reinforcer elements and the thickness Th described above are, as previously explained, the density of reinforcer elements 44 and the thickness Th of the composite 50. In the tyre 10, with the carcass ply 34 being obtained from the composite 50 by shaping a tyre green form, the density of reinforcer elements, as well as the thickness Th of the carcass ply 34 differ from those of the composite and vary depending on the proximity to or from the axis of rotation of the tyre. These variations are particularly dependent on the degree of shaping of the green form of the tyre, but also on its geometry. Particularly on the basis of the degree of shaping of the green form of the tyre and of its geometry, a person skilled in the art would be able to determine the features of the corresponding composite.

[0137] The diameter d of the reinforcer element is less than or equal to 0.95 mm, preferably less than or equal to 0.80 mm, more preferably less than or equal to 0.70 mm, and in this case is equal to 0.67 mm.

[0138] The ratio d/Th is strictly less than 0.65, preferably less than or equal to 0.62, and in this case is equal to 0.52.

[0139] The breaking strength of the carcass ply is greater than or equal to 300 daN.Math.cm.sup.1, preferably greater than or equal to 380 daN.Math.cm.sup.1, and more preferably greater than or equal to 410 daN.Math.cm.sup.1, and in this case is equal to 440 daN.Math.cm.sup.1.

[0140] Reinforcer Elements of the Carcass Ply of the Tyre 10

[0141] As schematically shown in FIG. 7, the reinforcer element 44 comprises an assembly formed by a multifilament strand 47 made of aromatic polyamide or aromatic co-polyamide and a multifilament strand 48 made of polyester, the two strands 47, 48 being helically wound around each other. The reinforcer element 44 is twist balanced. For the sake of the accuracy of the description, FIG. 8 is a section view of the reinforcer element 44 and distinguishes the monofilaments of each of the strands.

[0142] The selected aromatic polyamide in this instance preferably is a para-aramid known by the Teijin company trade name of Twaron 1000. The polyester is polyethylene terephthalate (PET), known by the Hyosung or Hailide company trade name of PET HMLS (High Modulus Low Shrinkage).

[0143] In some embodiments, not shown, the reinforcer element 44 comprises one or more layers of an adhesive composition coating the assembly.

[0144] Count of the Reinforcer Element 44

[0145] The count of the multifilament strand 47 made of aromatic polyamide or aromatic co-polyamide ranges from 140 to 210 tex, preferably from 150 to 190 tex, more preferably from 160 to 180 tex. In the first embodiment, the count of the strand 47 of the reinforcer element 44 is equal to 167 tex.

[0146] The count of the multifilament strand 48 made of polyester ranges from 100 to 210 tex, preferably from 120 to 190 tex, more preferably from 130 to 180 tex. In the first embodiment, the count of the strand 48 of the reinforcer element 44 is equal to 167 tex.

[0147] Twist of the Reinforcer Element 44

[0148] The twist R of the reinforcer element 44 ranges from 250 to 405 revolutions per metre, preferably from 250 to 390 revolutions per metre, more preferably from 250 to 380 revolutions per metre. In the first embodiment, the twist of the reinforcer element advantageously ranges from 275 to 365 revolutions per metre, preferably from 275 to 350 revolutions per metre, more preferably from 300 to 330 revolutions per metre, and in this case is equal to 315 revolutions per metre.

[0149] Twist Factor of the Reinforcer Element 44

[0150] The twist factor K of the reinforcer element 44 ranges from 5.2 to 6.5, preferably from 5.2 to 6.3, more preferably from 5.2 to 6.1.

[0151] In the first embodiment, the twist factor K of the reinforcer element 44 is equal to 315(167+167).sup.1/2/957=6.0.

[0152] The breaking strength of the reinforcer element 44 ranges from 30 to 45 daN, preferably from 33 to 43 daN, and more preferably from 35 to 41 daN, and in this case is equal to 40 daN.

[0153] Method for Manufacturing the Reinforcer Element 44

[0154] As previously described, each reinforcer element 44 is twist balanced, i.e. the two multifilament strands are wound with a substantially identical twist and the twist of the monofilaments of each multifilament strand is substantially zero. In a first step, each yarn of monofilaments is firstly individually twisted on itself following an initial twist equal to 315 revolutions per metre in a given direction, in this case the direction Z, in order to form a strand. Then, during a second step, the two strands are subsequently re-twisted together following a final twist equal to 315 revolutions per metre in the direction S, in order to obtain the assembly of the reinforcer element (cord). In subsequent steps, each assembly is coated with an adhesive composition, for example, an adhesive composition of the RFL (Resorcinol-Formaldehyde-Latex) type, and undergoes heat treatment steps in order to at least partly cross-link the adhesive composition.

[0155] Method for Manufacturing the Carcass Ply 34

[0156] In order to obtain the carcass ply 34, the composite 50 is firstly manufactured by immersing a plurality of reinforcer elements 44 in an elastomer composition, for example, by calendering. During such a calendering step, which is well known to a person skilled in the art, reinforcer elements are unwound and two strips, called skims, made from an elastomer composition are moved to either side of the reinforcer elements, in order to sandwich the reinforcer elements between the two skims. Thus, the reinforcer elements are immersed in the elastomer composition.

[0157] Method for Manufacturing the Tyre 10

[0158] The method for manufacturing the tyre is that which is conventionally used by a person skilled in the art. During this method, and as already previously described, various composites, including the composite 50 intended to form the carcass ply 34, are successively provided during a first series of assembly steps. The green form that is thus obtained is then shaped. Subsequently, other composites are provided that are intended to form the plies 16, 18, 19 of the crown 12 of the tyre 10. Finally, the green form that is thus obtained is vulcanized in order to obtain the tyre 10.

Tyre According to a Second Embodiment of the Invention

[0159] FIG. 4b shows a tyre 10 according to a second embodiment of the invention. The elements that are similar to those of the first embodiment are designated using identical reference signs, with the exception of the composite 52, the carcass reinforcement 33, the carcass ply 35 and the reinforcer element 45. For the sake of brevity, only the differences relative to the first embodiment will be described.

[0160] Unlike the tyre 10 according to the first embodiment, the tyre 10 according to the second embodiment in this case is intended for a vehicle of the SUV type and has a 255/50 R19 107W tyre size.

[0161] Thus, the sidewall height of the tyre 10 is less than or equal to 141 mm, and in this case is equal to 128 mm. The load index ranges from 100 to 115, and preferably from 100 to 105, and in this case is equal to 107. The nominal inflation pressure ranges from 175 kPa to 425 kPa, preferably from 200 kPa to 350 kPa, and more preferably from 220 kPa to 300 kPa, and in this case is equal to 290 kPa. The aspect ratio ranges from 35 to 70, preferably from 40 to 65, and more preferably from 50 to 60, and in this case is equal to 50. The nominal rim diameter ranges from 17 to 22 inches, preferably from 17 to 20 inches, and more preferably from 17 to 19 inches, and in this case is equal to 19 inches.

[0162] Carcass Ply of the Tyre 10

[0163] The density of reinforcer elements 45 in the composite 52 in this case is equal to 116 reinforcer elements per decimetre of composite 52. The thickness Th of the composite 52 is less than or equal to 1.45 mm, preferably less than or equal to 1.30 mm, more preferably less than or equal to 1.20 mm, and in this case is equal to 1.16 mm. The diameter d of the reinforcer element 45 is equal to 0.65 mm. The ratio d/Th in this case is equal to 0.56.

[0164] The breaking strength of the carcass ply 33 in this case is equal to 430 daN.Math.cm.sup.1.

[0165] Reinforcer Elements of the Carcass Ply of the Tyre 10

[0166] The count of the strand 47 of the reinforcer element 45 is also equal to 167 tex and the count of the strand 48 of the reinforcer element 45 is equal to 144 tex.

[0167] In this second embodiment, the twist of the reinforcer element 45 ranges from 250 to 340 revolutions per metre, preferably from 260 to 325 revolutions per metre, more preferably from 275 to 305 revolutions per metre, and in this case is equal to 290 revolutions per metre.

[0168] In this second embodiment, the twist factor K ranges from 5.2 to 5.5, preferably from 5.3 to 5.5, and even more preferably from 5.3 to 5.4, and in this case is 5.3.

[0169] The breaking strength of the reinforcer element 45 in this case is equal to 37 daN.

[0170] Method for Manufacturing the Reinforcer Element 45, the Carcass Ply 35 and the Tyre 10

[0171] The assembly of the reinforcer element 45 is manufactured, mutatis mutandis, relative to the reinforcer element 44 by applying a twist that is equal to 290 revolutions per metre.

[0172] The methods for manufacturing the carcass ply 35 and the tyre 10 are deduced, mutatis mutandis, from those previously described in the first embodiment.

[0173] Measures and Comparative Tests

[0174] Table 1 summarizes the features of the reinforcer elements 44, 45, respectively, of the tyres 10, 10 according to the invention, and of the reinforcer element ET of a tyre of the prior art and of a reinforcer element EC of a comparative tyre. The features of the corresponding composites CT, CC, 50 and 52 are also collated.

TABLE-US-00001 TABLE 1 Reinforcer element ET EC 44 45 Type of PET/PET PET/PET p-Aramid/ p-Aramid/ strands PET PET Twist (r/m) 420 270 315 290 Count of the 144/144 334/334 167/167 167/144 strands (tex) Twist factor 7.4 7.3 5.9 5.3 K Breaking 19 40 40 37 strength (daN) Composite CT CC 50 52 Density 123 80 110 116 (threads/dm) Th (mm) 1.17 1.47 1.28 1.16 d (mm) 0.62 0.96 0.67 0.65 d/Th 0.53 0.65 0.52 0.56 Breaking 228 328 440 430 strength (daN/cm)

[0175] Comparison of the Tyres

[0176] Table 2 summarizes the features of the tyres 10, 10 of the first and second embodiments according to the invention, of a tyre PT of the prior art having two carcass plies each formed by a composite CT and a tyre PC having a single carcass ply formed by a composite CC.

TABLE-US-00002 TABLE 2 PT PT PC 10 10 Tyre designation 215/75 R16 255/50 R19 255/50 R19 215/75 R16 255/50 R19 113/111R 107W 107W 113/111R 107W Number of 2 CT 2 CT 1 CC 1 50 1 52 carcass plies Sidewall height 161 128 128 161 128 (mm) Load index 113/111 107 107 113/111 107 Nominal inflation 475 290 290 475 290 pressure (kPa) Aspect ratio 75 50 50 75 50 Nominal rim 16 19 19 16 19 diameter (inches)

[0177] Firstly, on the one hand, the masses of the tyres PT and 10 and, on the other hand, the masses of the tyres PT, PC and 10 were compared by weighing the tested tyres. The results are indicated as a base 100 compared to the tyres PT and PT. A mass of less than 100 means that the tyre is lighter relative to the reference tyre PT or PT.

[0178] The deformation depth in the sidewall of the tyres PT, PT, PC, 10 and 10 was also compared before and after running-in. The deformation depth in the initial sidewall is measured on a new tyre before running-in. The deformation depth in the sidewall after running-in is determined by running each tested tyre over a determined distance and at a determined speed, in this case 200 km at 100 km/h at a pressure of 400 kPa.

[0179] The deformation depth in the sidewall is measured using a measuring gauge, for example, made by AKRON, which is positioned on a suitable and relevant zone of the tyre. The measurement is preferably taken on the zone at the equator.

[0180] The results of these various tests are collated in Table 3 below.

TABLE-US-00003 TABLE 3 PT PT PC 10 10 Initial 320 250 300 580 700 sidewall deformation (m) Sidewall 432 340 350 377 520 deformation after running-in (m) Evolution of +35% +36% +17% 35% 26% the deformation (%) Mass 100 / / 94 / Mass / 100 96 / 94

[0181] The tyre 10 has a reduced mass compared to the tyre PT and nevertheless allows an equivalent load to be carried despite the presence of a single carcass ply.

[0182] It is to be noted that the tyre 10 has a reduced mass compared to the tyres PT and PC. The tyre 10, by virtue of a carcass ply according to the invention, allows a higher load to be carried than the tyre PC and higher than the tyre PT, yet without requiring the use of two carcass plies.

[0183] The deformation depth of the tyre 10 according to the invention in the sidewall diminishes by 26% after running-in. It can be seen that the deformation depth in the sidewall of the tyre PT of the prior art increases by 35% after running-in at an equivalent load index. Furthermore, even though the deformation depth of the tyre 10 in the sidewall exceeds the perception threshold of the human eye on completion of its manufacturing method, after running-in, it can be seen that the deformation depth in the sidewall of the tyre 10 significantly decreases, then dropping below the perception threshold of the human eye, whereas the deformation depth in the sidewall of the tyre PT will significantly increase.

[0184] Unlike the tyre 10, the tyre 10 has a sidewall deformation depth that is below the perception threshold of the human eye before running-in, but nevertheless is relatively close to this threshold. As is the case for the tyre 10 after running-in, it can be seen that the deformation depth in the sidewall of the tyre 10 significantly decreases, in order to reach a value that is significantly below the perception threshold of the human eye, whereas the deformation depth in the sidewall of the tyre PT will significantly increase.

[0185] The difference in the deformation depth of the sidewall of the tyres 101 and 102 was also tested, with said tyres being architecturally similar to the tyre 10, except that the composites forming these tyres have the following features, collated in table 4 below:

TABLE-US-00004 TABLE 4 Reinforcer element 44 441 442 Type of strands p-Aramid/PET p-Aramid/PET p-Aramid/PET Twist (r/m) 315 325 290 Count of the strands 167/167 167/144 167/144 (tex) Twist factor K 5.9 6.0 5.3 Composite 50 50 50 Density (threads/dm) 110 116 116 Tyre 10 101 102 Initial sidewall 580 747 581 deformation (m) Sidewall deformation 377 538 482 after running-in (m) Evolution of the 35% 28% 17% deformation (%)

[0186] It can be seen that, by varying the count and the twist for the same tyre architecture, after running-in, as for the tyre 10, the deformation depth in the sidewall of the tyres 101 and 102 decreases, in order to reach a value below the perception threshold of the human eye.

[0187] Thus, as demonstrated by the above comparative tests, the invention involves a tyre with a sidewall height that is greater than or equal to 110 mm and a load index that is greater than or equal to 94 and involves combining a single carcass ply and a hybrid reinforcer element, allowing the tyre to be lightened, whilst making the deformations of sidewalls invisible to the client after a running-in period.

[0188] The invention is not limited to the previously described embodiments.

[0189] It will also be possible to combine the features of the various embodiments and alternative embodiments described or contemplated above, provided that these features are compatible with one another.