Tire Including A Knitted Fabric Having Variable Properties

Abstract

Tire (10) comprises a knit (44) comprising: columns of loops, the loops of one and the same column being arranged one after the other substantially in an overall direction referred to as the main direction and rows of said loops, the loops of one and the same row being arranged one beside the other substantially in an overall direction referred to as the transverse direction. The knit (44) comprises first and second zones (45.sub.1, 45.sub.2), each respectively having, at least in one of the main or transverse directions, a force FT.sub.100 and FS.sub.100 at 100% elongation that satisfies FS.sub.100<FT.sub.100, each force FT.sub.100 and FS.sub.100 being determined from a force-elongation curve obtained by applying standard ISO 13934-1:2013 to the knit before it is incorporated into the tire (10).

Claims

1. A tire including a knit comprising: columns of loops, the loops of one and the same column being arranged one after the other substantially in an overall direction referred to as the main direction; rows of said loops, the loops of one and the same row being arranged one beside the other substantially in an overall direction referred to as the transverse direction; the knit comprising first and second zones each respectively having, at least in one of the main or transverse directions, a force FT.sub.100 and FS.sub.100 at 100% elongation that satisfies FS.sub.100<FT.sub.100, each force FT.sub.100 and FS.sub.100 being determined from a force-elongation curve obtained by applying standard ISO 13934-1:2013 to the knit before it is incorporated into the tire.

2. The tire according to claim 1, wherein the first zone of the knit has a radius of curvature less than the radius of curvature of the second zone of the knit.

3. The tire according to claim 1, wherein the second zone is arranged radially on the outside of the first zone.

4. The tire according to claim 1, wherein each force FT.sub.100 and FS.sub.100 at 100% elongation of each first and second zone is measured in a direction of the knit that is substantially parallel to the circumferential direction of the tire.

5. The tire according to claim 1, wherein the first zone differs from the second zone in terms of at least one feature selected from the construction, the stitch size, the linear density of columns of stitches as measured in accordance with standard NF EN 14971, the linear density of rows of stitches as measured in accordance with standard NF EN 14971, the surface density of stitches as measured in accordance with standard NF EN 14971, or a combination of these features.

6. The tire according to claim 1, comprising a carcass reinforcement anchored in two beads and surmounted radially by a crown reinforcement itself surmounted by a tread which is connected to the beads by two sidewalls, each sidewall comprising at least the knit.

7. The tire according to claim 6, wherein the carcass reinforcement is anchored in each bead by being turned up around an annular structure of the bead so as to form a main strand and a turn up.

8. The tire according to claim 7, wherein the radial distance between the radially inner end of the knit and the radially median plane of the annular structure of the bead is less than or equal to 15 mm.

9. The tire according to claim 6, wherein the axial distance between the radially outer end of the knit and the axially outer end of a crown ply radially adjacent to the knit is less than or equal to 15 mm.

10. The tire according to claim 9, wherein the first zone extends radially between first and second points of the first zone, the first point of the first zone being radially on the inside in relation to the second point of the first zone.

11. The tire according to claim 10, wherein the first point of the first zone is radially on the inside in relation to the equator of the tire.

12. The tire according to claim 11, wherein the radial distance between the first point of the first zone and the radially median plane of the annular structure of the bead is less than or equal to 15 mm.

13. The tire according to claim 10, wherein the second point of the first zone is radially on the inside in relation to the equator of the tire.

14. The tire according to claim 13, wherein the radial distance between the second point of the first zone and the equator of the tire ranges from 3% to 10% of the section height of the tire.

15. The tire according to claim 10, wherein each first and second point of the first zone is radially on the outside in relation to the radially median plane of the annular structure of the bead.

16. The tire according to claim 1, wherein the second zone extends radially between first and second points of the second zone, the first point of the second zone being radially on the inside in relation to the second point of the second zone.

17. The tire according to claim 16, wherein the first point of the second zone is radially on the outside in relation to the equator of the tire.

18. The tire according to claim 17, wherein the radial distance between the first point of the second zone and the equator of the tire ranges from 3% to 10% of the section height of the tire.

19. The tire according to claim 16, wherein the axial distance between the second point of the second zone and the axially outer end of a crown ply radially adjacent to the second zone is less than or equal to 15 mm.

20. The tire according to claim 16, wherein the radially outer end of the knit is axially on the inside in relation to the axially outer end of a crown ply radially adjacent to the knit.

21. The tire according to claim 16, wherein the radially outer end of the knit is axially on the outside in relation to the axially outer end of a crown ply radially adjacent to the knit.

22. The tire according to claim 6, wherein the radially outer end of the knit is interposed radially between the carcass reinforcement and the crown reinforcement.

23. (canceled)

24. A method of manufacturing a tire according to claim 1, wherein the knit is embedded in an elastomer matrix.

Description

[0085] FIG. 1 is a view in cross section of a tire according to a first embodiment of the invention, comprising at least one knit;

[0086] FIG. 2 is a schematic development of the tire of FIG. 1, illustrating the axial distribution of knits;

[0087] FIG. 3 is a detailed view of a knit of the tire of FIG. 1;

[0088] FIG. 4 is a graph illustrating force-elongation curves for the knit of FIGS. 1 to 3;

[0089] FIGS. 5 and 6 are views respectively similar to those of FIGS. 1, 2, of a tire according to a second embodiment;

[0090] FIGS. 7 and 8 are views respectively similar to those of FIGS. 1, 2 of a tire according to a third embodiment; and

[0091] FIGS. 9 and 10 are views respectively similar to those of FIGS. 1, 2, of a tire according to a fourth embodiment.

[0092] In the following description, when using the word radial, it is appropriate to makes a distinction between several different uses of the word by a person skilled in the art. Firstly, the expression refers to a radius of the tire. It is in that sense that a point A is said to be radially inside a point B (or radially on the inside of the point B) if it is closer to the axis of rotation of the tire than is the point B. Conversely, a point C is said to be radially outside a point D (or radially on the outside of the point D) if it is further from the axis of rotation of the tire than is the point D. Progress radially inwards (or outwards) will mean progress toward smaller (or larger) radii. It is this sense of the word that applies also when radial distances are being discussed.

[0093] On the other hand, a reinforcing element or reinforcement is said to be radial when the reinforcing element or the reinforcing elements of the reinforcement make an angle greater than or equal to 65 and less than or equal to 90 with the circumferential direction.

[0094] An axial direction is a direction parallel to the axis of rotation of the tire. A point E is said to be axially inside a point F (or axially on the inside of the point F) if it is closer to the median plane of the tire than is the point F. Conversely, a point G is said to be axially outside a point H (or axially on the outside of the point H) if it is further from the median plane of the tire than is the point H.

[0095] The median plane M of the tire is the plane which is normal to the axis of rotation of the tire and which is situated equidistantly from the annular reinforcing structures of each bead.

[0096] A circumferential direction is a direction which is perpendicular both to a radius of the tire and to the axial direction.

[0097] Furthermore, any range of values denoted by the expression between a and b represents the range of values extending from more than a to less than b (namely excluding the end-points a and b), whereas any range of values denoted by the expression from a to b means the range of values extending from the end-point a as far as the end-point b, namely including the strict end-points a and b.

Examples of Tires According to the Invention

[0098] A frame of reference X, Y, Z, corresponding to the usual respectively axial (X), radial (Y) and circumferential (Z) directions of a tire has been depicted in the figures.

[0099] FIGS. 1 and 2 depict a tire according to a first embodiment of the invention and denoted by the general reference 10. The tire 10 is substantially of revolution about the axis X. The tire 10 here is intended for a passenger vehicle. The tire depicted is of size 205/55 R 16.

[0100] The tire 10 comprises a crown 12 comprising a crown reinforcement 14 comprising a working reinforcement 15 comprising two working layers 16, 18 of reinforcing elements and a protective or hoop reinforcement 17 comprising a protective ply 19. The crown reinforcement 14 is surmounted by a tread 20. In this instance, the protective reinforcement 17, in this instance the protective ply 19, is interposed radially between the working reinforcement 15 and the tread 20.

[0101] Two sidewalls 22 extend the crown 12 radially inwards. The tire 10 further comprises two beads 24 radially on the inside of the sidewalls 22 and connected to the crown 12 by the sidewalls 22 and each comprising an annular reinforcing structure 26, in this instance a bead wire 28, surmounted by a mass of filling rubber 30, as well as a radial carcass 32. The carcass reinforcement 32 is surmounted radially by the crown reinforcement 14.

[0102] The carcass reinforcement 32 preferably comprises a single carcass ply 34 of radial textile reinforcing elements, the ply 34 being anchored in each of the beads 24 by being turned up around the bead wire 28 so as to form, within each bead 24, a main strand 38 extending from the beads 24 through the sidewalls 22 to the crown 12, and a turnup 40, the radially outer end of the turnup 40 here being substantially midway up the height of the tire 10. The carcass reinforcement 32 thus extends from the beads 24 through the sidewalls 22 to the crown 12. As an alternative, the radial reinforcing elements are made of metal. The tire 10 also comprises an inner liner 42, generally made of butyl, arranged axially and radially on the inside of the carcass reinforcement 32.

[0103] The working plies 16, 18 comprise metal or textile reinforcing elements conventional to a person skilled in the art and forming an angle from 15 to 40, preferably ranging from 20 to 30 and here equal to 26 with the circumferential direction Z of the tire. The reinforcing elements of the working plies are crossed from one working ply to the other.

[0104] The protective ply 19 comprises metal or textile reinforcing elements likewise conventional to a person skilled in the art and forming an angle ranging from 0 to 10 with the circumferential direction Z of the tire.

[0105] Furthermore, the tire comprises an additional reinforcement 41, comprising at least one additional ply 43. Each additional ply 43 comprises at least one knit 44. The additional ply 43 and, in this instance, the knit 44, are arranged axially on the outside of the carcass reinforcement 34. Thus, as illustrated in FIG. 1, each sidewall 22 comprises a knit 44.

[0106] The radially outer end P4 of the knit 44 is axially on the inside in relation to the axially outer end P3 of the crown ply 18 radially adjacent to the knit 44. Furthermore, the radially outer end P4 of the knit 44 is interposed radially between the carcass reinforcement 32 and the crown reinforcement 14.

[0107] The axial distance D4 between the radially outer end P4 of the knit 44 and the axially outer end P3 of the crown ply 18 radially adjacent to the knit 44 is less than or equal to 15 mm, preferably less than or equal to 10 mm, and more preferably less than or equal to 5 mm. Here, D4=5 mm.

[0108] The knit 44 extends, in the bead, axially between the main strand 38 and the turnup 40 of the carcass reinforcement 32. As an alternative, it is possible to conceive of an embodiment in which the knit extends, in the bead, axially on the outside of the turnup 40.

[0109] The radial distance D1 between the radially inner end P2 of the knit 44 and the radially median plane P1 of the annular structure 26 of the bead 24 is less than or equal to 15 mm, preferably less than or equal to 10 mm, and more preferably less than or equal to 5 mm. Here, D1=5 mm.

[0110] Each working ply 16, 18, protective ply 19, carcass ply 34 and additional ply 43 comprises an elastomer matrix in which the reinforcing elements of the corresponding ply are embedded. The compositions of the elastomer matrixes of the working plies 16, 18, protective ply 19, carcass ply 34 and additional ply 43 are compositions that are conventional for skimming reinforcing elements and contain in the conventional way a diene elastomer, for example natural rubber, a reinforcing filler, for example carbon black and/or silica, a crosslinking system, for example a vulcanization system, preferably containing sulphur, stearic acid and zinc oxide, and possibly a vulcanization retardant and/or accelerator and/or various additives.

[0111] FIG. 3 depicts the knit 44. The knit 44 comprises columns C1, C2, C3, C4 of loops V and rows R1, R2, R3, R4 of loops V. The loops V of one and the same column Ci are arranged one after another substantially in an overall direction referred to as the main direction Y1. The loops V of one and the same row Ri are arranged one beside the other substantially in an overall direction referred to as the transverse direction Z1.

[0112] The main Y1 and transverse Z1 directions make, with respect to one another, an angle of between 75 and 105, preferably between 85 and 95. Here, the main Y1 and transverse Z1 directions are substantially perpendicular to one another.

[0113] The main overall direction Y1 makes an angle at most equal to 30 with the radial direction Y of the tire 10. When the knit is laid on a flat support, the main overall direction Y1 makes an angle here equal to 0 with the radial direction Y of the tire 10, the main overall direction Y1 of the knit 44 being essentially parallel to the radial direction Y of the tire 10.

[0114] The transverse overall direction Z1 makes an angle at most equal to 10 with the circumferential direction Z of the tire 10 and in this instance makes an angle equal to 0, the transverse overall direction Z1 of the knit 44 being substantially parallel to the circumferential direction Z of the tire 10.

[0115] The knit 44 has a construction of the jersey type and has been produced using a knitting method conventional to those skilled in the art in this field. The knit 44 has, in the direction Y1, a thickness ranging from 0.7 to 3 mm, preferably 0.8 to 2.6 mm, and here equal to 1.6 mm.

[0116] The number of stitches of the knit per unit area, measured in accordance with standard NF EN 14971, is less than or equal to 700 stitches.Math.cm.sup.2, preferably less than or equal to 100 stitches.Math.cm.sup.2 and more preferably less than or equal to 75 stitches.Math.cm.sup.2. The number of knit stitches per unit area is also greater than or equal to 5 stitches.Math.cm.sup.2, preferably greater than 10 stitches.Math.cm.sup.2 and more preferably, greater than or equal to 15 stitches.Math.cm.sup.2. In this particular instance, the density of stitches per unit area is equal to 15 stitches.Math.cm.sup.2.

[0117] The tire 10 comprises a first zone 45.sub.1 and a second zone 45.sub.2 of the knit 44. Referring back to FIGS. 1 and 2, the first zone 45.sub.1 of the knit 44 has a radius of curvature smaller than the radius of curvature of the second zone 45.sub.2 of the knit 44. The second zone 45.sub.2 is arranged radially on the outside of the first zone 45.sub.1.

[0118] The first zone 45.sub.1 differs from the second zone 45.sub.2 in terms of at least one feature selected from the construction, the stitch size, the linear density of columns of stitches as measured in accordance with standard NF EN 14971, the linear density of rows of stitches as measured in accordance with standard NF EN 14971, the surface density of stitches as measured in accordance with standard NF EN 14971, or a combination of these features. In this particular instance, the first and second zones 45.sub.1, 45.sub.2 differ from one another in terms of the linear density of rows of stitches and therefore also in terms of the number of stitches per unit area (the linear density of columns of stitches being the same in both the first and second zones 45.sub.1, 45.sub.2).

[0119] FIG. 4 depicts force-elongation curves obtained by applying standard ISO 13934-1:2013 to the knit before it is incorporated into the tire. In this instance, the knit has no elastomer matrix.

[0120] Curve I illustrates the variation in force as a function of the elongation of the second zone 45.sub.2 of the knit 44 in the transverse direction Z1. Curve II illustrates the variation in force as a function of the elongation of the first zone 45.sub.1 of the knit 44 in the transverse direction Z1. Curve III illustrates the variation in force as a function of elongation of the knit in the main direction Y1.

[0121] As can be seen from FIG. 4, the knit 44 has particular properties of elongation at break and of maximum force which are measured in accordance with standard ISO 13934-1:2013, and properties of force at 50% and 100% elongation which are determined from a force-elongation curve obtained by applying standard ISO 13934-1:2013 to the knit 44 before it is incorporated into the tire 10.

[0122] Each first and second zone 45.sub.1,45.sub.2 has, in the main direction Y1, in this instance the radial direction Y of the tire 10, a force at 100% elongation denoted FTY.sub.100 and FSY.sub.100 respectively, each force FTY.sub.100 and FSY.sub.100 being determined from a force-elongation curve obtained by applying standard ISO 13934-1:2013. However, only the force-elongation curve for the first zone 45.sub.1 has been reproduced, with FTY.sub.100=549 N.

[0123] Each first and second zone 45.sub.1, 45.sub.2 has, in the transverse direction Z1, in this instance the circumferential direction Z of the tire, a force at 100% elongation respectively denoted FTZ.sub.100 and FSZ.sub.100 that satisfies FSZ.sub.100<FTZ.sub.100, each force FTZ.sub.100 and FSZ.sub.100 being determined from a force-elongation curve obtained by applying the standard ISO 13934-1:2013. Here, FT.sub.100=FTZ.sub.100=542 N and FS.sub.100=FSZ.sub.100=462 N. We therefore have an FZT.sub.100 and FSZ.sub.100 that satisfy FT.sub.100/FS.sub.100>1.05, preferably FT.sub.100/FS.sub.100>1.10 and more preferably FT.sub.100/FS.sub.100>1.15 and FT.sub.100/FS.sub.100<2.00, preferably FT.sub.100/FS.sub.100<1.80 and more preferably FT.sub.100/FS.sub.100<1.60. Here, FT.sub.100/FS.sub.100=1.17.

[0124] The knit 44 is made up of one or more filamentary elements F of a nonelastomeric material. The or each nonelastomeric material is selected from a polyester, a polyamide, a polyketone, a cellulose, a mineral fibre, a natural fibre or a mixture of these materials.

[0125] The or each filamentary element F comprises at least one multifilament strand comprising several elementary monofilaments. In this particular instance, the or each filamentary element E comprises two strands of nylon each of 140 tex each overtwisted at 250 turns.Math.m.sup.1 in a first direction then plied in a helix around one another at 250 turns.Math.m.sup.1 in a second direction that is the opposite of the first direction.

[0126] The first zone 45.sub.1 extends radially between first and second points Z1, Z2 of the first zone 45.sub.1. The first point Z1 is radially on the inside in relation to the second point Z2. The first point Z1 is also radially on the inside in relation to the equator E of the tire 10. The second point Z2 is radially on the inside in relation to the equator E of the tire 10. Each first and second point Z1, Z2 is radially on the outside in relation to the radially median plane P1 of the annular structure 26 of the bead 24.

[0127] The radial distance d1 between the first point Z1 and the radially median plane P1 of the annular structure 26 of the bead 24 is less than or equal to 15 mm, preferably less than or equal to 10 mm, and more preferably less than or equal to 5 mm. Here, d1=D1=5 mm.

[0128] The radial distance d2 between the second point Z2 and the equator E of the tire 10 ranges from 3% to 10% of the section height H of the tire 10. Here H=112.75 mm and d2=7 mm.

[0129] The second zone 45.sub.2 extends radially between first and second points Z3, Z4 of the second zone 45.sub.2. The first point Z3 of the second zone 45.sub.2 is radially on the inside in relation to the second point Z4 of the second zone 45.sub.2. The first point Z3 of the second zone 45.sub.2 is radially on the outside in relation to the equator E of the tire 10.

[0130] The radial distance d3 between the first point Z3 of the second zone 45.sub.2 and the equator E of the tire 10 ranges from 3% to 10% of the section height H of the tire 10. Here H=112.75 mm and d3=7 mm.

[0131] The axial distance d4 between the second point Z4 of the second zone 45.sub.2 and the axially outer end P3 of a crown ply 18 radially adjacent to the second zone 45.sub.2 is less than or equal to 15 mm, preferably less than or equal to 10 mm, and more preferably less than or equal to 5 mm. Here, d4=D4=5 mm.

[0132] A method of manufacturing the tire as described hereinabove will now be described. Only the main steps relating to the invention will be described, it being easy for the other steps to be carried out on the basis of the general knowledge of a person skilled in the art.

[0133] During the course of the method, a green tire comprising the beads 24, the sidewalls 22 and the carcass reinforcement 32, in this instance the carcass ply 34, is formed.

[0134] In a first alternative form of the method, the knit 44 is embedded in its elastomer matrix so as to obtain the additional ply 43, for example by skimming the knit 44 between two strips of elastomer matrix. This additional ply 43 is then added to the green tire formed beforehand. Next, the crown reinforcement 14 and the tread 20 are added.

[0135] In a second alternative form, a first strip of elastomer matrix is added to the green tire. Then, the knit 44 is added to the first strip of elastomer matrix. Next, a second strip of elastomer matrix is added to the knit 44. Finally, the crown reinforcement 14 and the tread 20 are added. When the green tire is cured to form the tire 10, the elastomer matrix of the first and second strips flows through the knit 44. Thus the knit 44 becomes embedded in its elastomer matrix.

[0136] In this second alternative form, the knit 44 forms a monolithic ring having an axis of revolution. The ring is radially deformable, namely deformable at right angles to its axis of revolution, between a position at rest and a deformed position. Thus, the knit 44 is deformed radially from its state at rest into its deformed state then added axially around the green tire in its deformed state, then the knit 44 is released from its deformed state so that the knit tightly encircles the green tire. Once in position on the green tire, the axis of revolution of the monolithic ring is substantially parallel to and coincident with the axis of the tire.

[0137] Second, third and fourth embodiments of the invention will now be described with reference respectively to FIGS. 5, 6 and 7, 8 and 9, 10. Elements similar to those described in the previous embodiment are denoted by identical references.

[0138] The tire according to the second embodiment in FIGS. 5 and 6 comprises two knits 441 and 442. The knit 441 comprises a radially inner end denoted P2 and a radially outer end P5. The knit 442 comprises a radially inner end denoted P6 and a radially outer end P4. Each knit 441 and 442 comprises first and second zones 45.sub.1,1, 45.sub.1,2 and 45.sub.2,1, 45.sub.2,2, respectively.

[0139] Unlike the tire according to the first embodiment, the tire according to the third embodiment in FIGS. 7 and 8 is such that the radially outer end P4 of the knit 44 is axially on the outside in relation to the axially outer end P3 of the crown ply 18 radially adjacent to the knit 44.

[0140] Unlike the tire according to the second embodiment in FIGS. 5 and 6, the tire of the fourth embodiment in FIGS. 9 and 10 comprises two knits 441, 442, in this instance the knits of the second embodiment, arranged axially on the inside of the carcass reinforcement 32.

[0141] Comparative Tests

[0142] In addition to reducing the difference in capacity to reinforce and to elongate between various zones of the knit which capacity is generated during the shaping of the tire, the tire according to the invention offers an excellent compromise between mass and cornering stiffness under heavy loading.

[0143] The tire 10 according to the invention and three tires T1, T2 and T3 of the prior art were compared. The tire 10 has an architecture identical to the tire according to the first embodiment and comprises a knit made up of one or more filamentary elements of a nonelastomeric material, in this instance nylon.

[0144] The characteristics of the knit 44 used are described in tables 1 (properties relating to maximum force, force at break, elongation at 50% and 100% in accordance with standard ISO 13934-1:2013 applied to the knit prior to its incorporation into the tire) and 2 (properties relating to the linear density of rows of stitches, linear density of columns of stitches, surface density of stitches per unit area, in accordance with standard NF EN 14971 of 2006) below.

TABLE-US-00001 TABLE 1 Tire 10 Transverse Transverse Main direction Y1 - direction Z1 - direction Z1 - first zone 45.sub.1 first zone 45.sub.1 second zone 45.sub.2 Curve (FIG. 4) III II I Nature of the N94/2 N94/2 N94/2 strand Construction Welted jersey Welted jersey Welted jersey of the knit Maximum 1391 1320 1297 force (N) Elongation at 167 152 182 break (%) Force at 100% 549 542 462 elongation Force at 50% 148 48.1 39.1 elongation

TABLE-US-00002 TABLE 2 Tire 10 First zone 45.sub.1 Second zone 45.sub.2 Nature of the N94/2 N94/2 strand Construction of the Welted jersey Welted jersey knit Method used in B B Standard NF EN 14971 Measurement face Technical right side Technical right side Mean of individual 3.0 3.0 results (columns/cm) Mean of individual 5.2 4.8 results (rows/cm) Surface density 15.6 14.4 (stitches/cm.sup.2)

[0145] The tire T1 is identical to the tire 10 except that it has no knit. The tire T2 comprises, in addition to the elements of the tire T1, a second carcass ply. The tire T3 is identical to the tire T1 except that its sidewalls have an additional thickness of 10 mm by comparison with that of the sidewalls of the tire T1.

[0146] The various tires T1 to T3 and 10 were subjected to a drift thrust Dz test as described hereinbelow. The mass of each tire T1 to T3 and 10 was also measured.

[0147] The results are given to base 100 with respect to the tire T1. Thus, for drift thrust Dz, the greater the extent to which the value is above 100, the better the drift thrust of the tire tested compared with the tire T1. In the case of mass, the greater the extent to which the value is lower than 100, the heavier the tire tested is in relation to the tire T1.

[0148] To measure the drift thrust Dz, each tire was driven at a constant speed of 80 km/h on a suitable automatic machine (machine of the flat track type marketed by MTS), varying the load denoted Z at a relatively large cornering angle of 8 degrees, and the drift thrust was measured continuously and the cornering stiffness denoted D (corrected for the thrust at zero drift) was identified by recording, by way of sensors, the transverse load on the wheel as a function of this load Z; the cornering stiffness is thus obtained. The reported value for Dz is thus obtained for a chosen load here of 482 daN.

[0149] The results of these tests are collated in table 3 below.

TABLE-US-00003 TABLE 3 Tire T1 T2 T3 10 Weight (base 100) 100 93 81 96 Dz (base 100) 100 100 108 105

[0150] It will be noted that the tire 10 according to the invention has a mass relatively similar to that of the tire T1 and, in any event, lower than that of the tire T2 and especially that of the tire T3. Furthermore, it will be noted that the tire 10 according to the invention has a cornering stiffness Dz higher than those of the tires T1 and T2. Thus, the tire 10 according to the invention offers a better compromise between mass and cornering stiffness than do the tires T1 to T3.

[0151] The advantages described hereinabove are obviously on top of the main advantage connected with the invention namely that of reducing the difference in the capacity to reinforce and to elongate of the various zones of the knit which capacity is generated during the shaping of the tire.

[0152] The invention is not limited to the embodiments described hereinabove.

[0153] It may also be possible to combine the features of the various embodiments described or envisaged above, as long as these are compatible with one another.