Tyre for racing bicycle wheel

Abstract

Tyre (100) for racing bicycle wheels, the tyre comprising a carcass structure (2) and a tread band (6) arranged in a radially outer position relative to the carcass structure (2); wherein the carcass structure (2) comprises a single carcass ply (3) flipped around an annular anchoring structure (4a, 4b), and wherein the free edges (11) of the carcass ply (3) lie radially juxtaposed one above the other. The width of the protective layer (16) is equal to or less than 50% of the width of the tire (100). The first sidewall reinforcing ply (14) and the second sidewall reinforcing ply (15) are arranged axially between the respective annular anchoring structures (4a, 4b) and the equatorial plane (X) of the tyre. In the first juxtaposition area (17), the protective layer (16), the first sidewall reinforcing ply (14) and the juxtaposition portion (12) of the edge of the carcass ply are radially juxtaposition in a predetermined order. In the second juxtaposition area (18), the protective layer (16), the second sidewall reinforcing ply (15) and the juxtaposition portion (12) of the edge of the carcass ply are radially juxtaposition in a predetermined order. The first juxtaposition region (17) and the second juxtaposition region (18) are arranged at respective distances from the equatorial plane (X) between 3% and 24% of the width of the tyre (100).

Description

Field of the Invention

[0001] The present invention relates to a tire for a bicycle wheel, preferably to a tire for a racing bicycle wheel.

[0002] A racing bicycle is a high-performance bicycle used for racing on roads or tracks. Such bicycles include those that meet the rules established by the Union Cycliste Internationale (UCI) - Part 1 - General Organization of Cycling - Chapter 3: Equipment, Section 2. Such bicycles also include recumbent bicycles, time trial bicycles, and / or triathlon bicycles. In addition, such bicycles also include so-called "fitness bicycles" (racing bicycles for recreational use).

[0003] The inflation pressure for the use of tires for racing bicycle wheels is above 3 bar, more preferably above 4 bar, and depending on the weight of the rider and the width of the tire, their inflation pressure can reach 8 bar or more.

[0004] The assembled diameter of the tire for a racing bicycle wheel is less than or equal to approximately 622 mm (which, depending on the width of the tire, can correspond to an outer diameter between approximately 675 mm and 700 mm), and the width of the inflated tire is between approximately 23 mm and 35 mm. Background Art

[0005] Tires for bicycle wheels generally include a carcass structure that is turned around a pair of bead cores and a tread band that is arranged in a radially outer position relative to the carcass structure.

[0006] The carcass structure is intended to withstand the inflation pressure and support the weight of the bicycle and the rider. The carcass structure includes one or more carcass plies, each of which includes a plurality of reinforcing cords oriented appropriately. For a tire for a racing bicycle wheel, usually a single carcass ply is turned around a pair of bead cores so that three layers of the carcass ply are radially juxtaposed on top of each other at the tread band.

[0007] The tread band is intended to allow the tire to grip the asphalt.

[0008] The bead core, also known as the annular anchoring structure, has the task of ensuring the anchoring of the tire to the wheel rim.

[0009] In a radially inner position relative to the carcass structure, an air chamber is usually provided, and pressurized air is introduced into the air chamber.

[0010] However, there are tire types known as "tubeless", i.e., tires without an air chamber. In such tires, the pressurized air acts directly on the carcass structure, and a layer called a "liner" is provided, which extends between a pair of bead cores and is radially disposed between the carcass structure and the tread band, or alternatively, is disposed at a radially inner position relative to the carcass to achieve an airtight seal. The shapes of the carcass structure, the annular anchoring structure, and the wheel rim are formed such that they are mutually anchored to ensure an airtight seal.

[0011] There is also a tire type called "tubeless ready", which has no air chamber and in which the "liner" is replaced by a ply extending from bead core to bead core (referred to as "bead-to-bead"), which extends between a pair of bead cores. The ply extending from bead core to bead core is radially disposed between the tread band and the carcass structure. The airtight seal is ensured by a sealant, which is interposed between the bicycle tire and the rim and forms a thin airtight film. The shapes of the carcass structure, the annular anchoring structure, and the wheel rim are formed such that they are mutually anchored to ensure an airtight seal.

[0012] To avoid debris from entering the carcass structure, thereby avoiding possible puncturing of the air chamber and / or damage to the carcass structure itself, a protective layer (also referred to as a "puncture protection layer" or "breaker") can be provided at a radially inner position relative to the tread band. Such a protective layer can be radially disposed inside the carcass structure or radially disposed between the carcass structure and the tread band.

[0013] For example, tires for bicycle wheels are known from EP 0 484 831, EP 3 575 109, and FR 3067982. Summary of the Invention

[0014] The term "equatorial plane" of a tire refers to a plane perpendicular to the axis of rotation of the tire and dividing the tire into two symmetrically equal parts.

[0015] The terms "radial" and "axial" and the expressions "radially inner / outer" and "axially inner / outer" are used with reference to the direction perpendicular to the axis of rotation of the tire and the direction parallel to the axis of rotation of the tire, respectively.

[0016] The expressions "axially inner" and "axially outer" denote positions closer to and farther from the equatorial plane, respectively.

[0017] The expressions "radially inner" and "radially outer" denote positions closer to and farther from the axis of rotation of the tire, respectively.

[0018] The terms "circumferential" and "circumferentially" are used with reference to the annular extension direction of the tire (i.e., the rolling direction of the tire), which direction corresponds to a direction lying in a plane coinciding with or parallel to the equatorial plane of the tire.

[0019] The term "elastomeric material" refers to a composition comprising at least one elastomeric polymer and at least one reinforcing filler. Preferably, such a composition further comprises additives such as, for example, crosslinking agents and / or plasticizers. Due to the presence of crosslinking agents, this material can be crosslinked by heating.

[0020] The term "cord" or the expression "reinforcing cord" is intended to denote an element constituted by one or more linear elements (hereinafter also referred to as "wires"), which element is possibly coated with or incorporated into an elastomeric material matrix.

[0021] The "diameter" of a cord or wire is the thickness of the cord or wire measured in accordance with the provisions of method BISFA E10 (International Bureau for the Standardization of Man-Made Fibres, internationally recognized method for measuring steel tire cords, 1995 edition).

[0022] The "number of cords" of a ply, carcass ply or fabric is the number of reinforcing cords per unit length in such ply / carcass ply / fabric. The number of cords can be measured in TPI (threads per inch).

[0023] The "linear density" or "count" of a cord or wire is the weight of the reinforcing cord per unit length. The linear density can be measured in dtex (grams per 10 km length).

[0024] The "assembly diameter" of a tire is the diameter of the tire measured at the inner diameter of the bead core in accordance with the provisions of ETRTO (European Tyre and Rim Technical Organization) or ISO (International Organization for Standardization), the bead core being used to anchor the tire to the rim of the wheel.

[0025] The "width" of a tire is the maximum axial extension of the tire in a reference plane perpendicular to the equatorial plane of the tire and tangent to the maximum diameter of the tire, this width being measured between the axial outer points of said extension of the tire in said reference plane.

[0026] The "width" of a tire component is intended to denote the maximum axial extension of the component measured along the tire in a plane perpendicular to the equatorial plane of the tire and tangent to the maximum diameter of the tire.

[0027] The term "rolling resistance" means the force that impedes the rolling of a tire and, more generally, refers to the energy consumed by the tire per unit distance traveled during rolling. The measurement of rolling resistance can be carried out, for example, in accordance with the method described below.

[0028] The term "radius of curvature" of a part of the cross-sectional profile of a tire means the radius of the circle that best approximates that profile part.

[0029] The term "inflated profile" of a tire means the shape of the radially outer profile of the tire cross-section when the tire is inflated to the working pressure.

[0030] The term "width of an inflated tire" refers to the maximum axial extension (or "maximum chord") of the tire measured when the tire is inflated to the working pressure. The width of an inflated tire corresponds to the projected width of the tire in a plane perpendicular to the tire equatorial plane and tangent to the tire's maximum diameter, and this width corresponds to the dimension of the segment with the two outermost axial points of the tire as endpoints when the tire is inflated to the working pressure.

[0031] In the remainder of this specification and in the claims that follow, when referring to certain numerical values, these values must be considered to be preceded by the term "about".

[0032] In the remainder of this specification and in the claims that follow, when referring to certain numerical ranges, the extreme values are also included in that numerical range.

[0033] The present applicant has found that in order to optimize the performance of a tire for a bicycle wheel, many requirements must be considered, which are interrelated but in some cases conflict with each other.

[0034] The present applicant points out that for the specific case of a tire for a racing bicycle wheel, high maneuverability is required even at relatively high speeds, and it is lightweight and has low rolling resistance.

[0035] The present applicant points out that the maneuverability of a bicycle (track accuracy, responsiveness and control of traction and braking, resistance to lateral thrust) generally increases with the increase in the structural stiffness of the tire.

[0036] According to the experience of the present applicant, greater structural stiffness can be obtained by increasing the inflation pressure of the tire, but too high an inflation pressure will have a negative impact on other important performance characteristics of the tire, such as road holding (i.e., the ability to maintain the track in a curve) and comfort (i.e., the ability to absorb road surface undulations and irregularities), thus making the cyclist feel a reduction in safety and maneuverability.

[0037] In addition, due to the current trend of increasing the width of the tire, and under the same conditions, a wider tire requires a lower inflation pressure, so the present applicant believes that it is not appropriate to seek greater tire structural stiffness by increasing the inflation pressure.

[0038] According to the experience of the present applicant, the structural stiffness of a tire can be increased by increasing the number of carcass plies. However, increasing the number of carcass plies results in an increase in the weight of the tire and an increase in the size of the unsprung mass, thereby reducing the perceived maneuverability.

[0039] Furthermore, the present applicant has also observed that as the number of carcass plies increases and thus as the structural stiffness of the entire tire increases, the inflation profile of the tire tends to have a radius of curvature of the radially outer contour of the tire that is smaller at the tread band portion in contact with the ground during straight running. In such a portion, the tread band is indeed radially larger relative to the tread band portion in contact with the ground during cornering.

[0040] According to the experience of the present applicant, this results in a non-uniform transition between straight running and cornering, thereby giving a feeling of poor predictability and thus a lower perceived maneuverability.

[0041] The present applicant believes that by providing a large number of radially juxtaposed structural components for the tire in the region in contact with the ground during cornering, and a smaller number of radially juxtaposed structural components for the tire in the region in contact with the ground during straight running, on the one hand, the structural stiffness of the tire can be increased only in the region of the tire that is more stressed during cornering, and on the other hand, the radius of curvature of the radially outer contour of the tire can be increased at the portion of the tire in contact with the ground during straight running.

[0042] The present applicant has found that this can improve the maneuverability by providing an increased structural stiffness for the tire during cornering, and can make the radius of curvature of the radially outer contour of the tire more constant at the tread band, thereby making the transition between straight running and cornering less abrupt, and thus making the behavior during cornering more predictable.

[0043] The present applicant has finally found that if a portion of the structural components already provided in a tire for a racing bicycle wheel is radially juxtaposed, rather than juxtaposing new or other structural components, to form a region of increased structural stiffness, the weight of the tire is not negatively affected.

[0044] Therefore, the present invention relates to a tire for a racing bicycle wheel, the tire comprising a carcass structure and a tread band arranged in a radially outer position relative to the carcass structure.

[0045] Preferably, the carcass structure comprises a single carcass ply that is turned around a first annular anchoring structure and a second annular anchoring structure, and wherein the free edges of the carcass ply are radially juxtaposed on top of each other at the juxtaposed portion of the edges of the carcass ply.

[0046] Preferably, a protective layer is provided having a width equal to or less than 50% of the width of the tire.

[0047] Preferably, a first sidewall reinforcing ply is provided, which is axially disposed between the first annular anchoring structure and the equatorial plane of the tire.

[0048] Preferably, a second sidewall reinforcing ply is provided, which is axially disposed between the second annular anchoring structure and the equatorial plane.

[0049] Preferably, in the first juxtaposed region, the juxtaposed portions of the edges of the protective layer, the first sidewall reinforcing ply, and the carcass ply are radially juxtaposed in a predetermined order.

[0050] Preferably, in the second juxtaposed region, the juxtaposed portions of the edges of the protective layer, the second sidewall reinforcing ply, and the carcass ply are radially juxtaposed in a predetermined order.

[0051] Preferably, the first juxtaposed region and the second juxtaposed region are disposed on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are between 3% and 24% of the tire width.

[0052] The applicant has found that disposing the first juxtaposed region and the second juxtaposed region at positions where the corresponding distances from the equatorial plane are between 3% and 24% of the tire width provides increased structural stiffness to the portions of the tire that contact the ground during a cyclist entering a bend and turning, thereby improving the accuracy of the trajectory in the bend and the resistance to lateral thrust.

[0053] Furthermore, the said arrangement of the first juxtaposed region and the second juxtaposed region does not involve or hardly involves the portions of the tire that contact the ground during straight running and that generally have a tread band portion with a larger radius of curvature. The applicant has found that in this way, with respect to the tread band portion that contacts the ground during turning, the structure of the tire radially inside the tread band has a smaller thickness in the radial direction at the tread band portion that contacts the ground during straight running. This allows obtaining a constant, or substantially constant, or in any case very similar radius of curvature of the radially outer contour of the tire between the portions of the tire that contact the ground during straight running and during turning. In this way, the transition between straight running and turning (and vice versa) is very gradual, greatly increasing the cyclist's comfort as well as the feeling of safety and maneuverability.

[0054] The present invention may exhibit at least one of the following preferred features.

[0055] Preferably, the protective layer is made of a ply.

[0056] Preferably, in the first juxtaposed region and the second juxtaposed region, the tire comprises five radially juxtaposed plies.

[0057] Preferably, in an axial intermediate position between the first juxtaposed region and the second juxtaposed region, the tire includes four radially juxtaposed ply plies.

[0058] Preferably, the carcass structure is a single-ply type carcass structure.

[0059] Preferably, the first juxtaposed region and the second juxtaposed region are arranged on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are equal to or greater than 3% of the tire width.

[0060] Preferably, the first juxtaposed region and the second juxtaposed region are arranged on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are equal to or greater than 5% of the tire width.

[0061] Preferably, the first juxtaposed region and the second juxtaposed region are arranged on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are preferably equal to or less than 20% of the tire width.

[0062] Preferably, the first juxtaposed region and the second juxtaposed region are arranged on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are equal to or less than 18% of the tire width.

[0063] Preferably, the first juxtaposed region and the second juxtaposed region are arranged on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are between 3% and 20% of the tire width.

[0064] Preferably, the first juxtaposed region and the second juxtaposed region are arranged on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are between 3% and 18% of the tire width.

[0065] Preferably, the first juxtaposed region and the second juxtaposed region are arranged on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are between 5% and 20% of the tire width.

[0066] Preferably, the first juxtaposed region and the second juxtaposed region are arranged on axially opposite sides with respect to the equatorial plane and the corresponding distances from the equatorial plane are between 5% and 18% of the tire width.

[0067] Preferably, the width of the tread band is equal to or less than 50% of the tire width, more preferably equal to or less than 45% of the tire width.

[0068] Preferably, the width of the tread band is equal to or greater than 30% of the tire width, more preferably equal to or greater than 35% of the tire width.

[0069] Preferably, the width of the tread band is between 30% and 50% of the tire width, more preferably between 35% and 50% of the tire width, even more preferably between 30% and 45% of the tire width, and even more preferably between 35% and 45% of the tire width, for example about 40% of the tire width.

[0070] Preferably, the width of the protective layer is equal to or less than 50% of the tire width.

[0071] Preferably, the width of the protective layer is equal to or greater than 20% of the tire width, more preferably equal to or greater than 22% of the tire width.

[0072] Preferably, the width of the protective layer is between 20% and 45% of the tire width, more preferably between 22% and 40% of the tire width, and even more preferably between 22% and 35% of the tire width.

[0073] In order to allow the tire to have sufficient puncture resistance while reducing the weight of the tire, the applicant has found that it is advantageous for the width of the protective layer to be equal to, preferably less than, the width of the tread band.

[0074] Preferably, the width of the protective layer is equal to or less than 95% of the width of the tread band, more preferably equal to or less than 90% of the width of the tread band, and even more preferably equal to or less than 85% of the width of the tread band.

[0075] Preferably, the width of the protective layer is equal to or greater than 50% of the width of the tread band, more preferably equal to or greater than 60% of the width of the tread band, more preferably equal to or greater than 70% of the width of the tread band, and even more preferably equal to or greater than 75% of the width of the tread band.

[0076] Preferably, the width of the protective layer is between 50% and 95% of the tread band, more preferably between 50% and 90% of the tread band, and even more preferably between 50% and 85% of the tread band.

[0077] Preferably, the protective layer is symmetrically arranged with respect to the equatorial plane.

[0078] Preferably, the first juxtaposed region and the second juxtaposed region are symmetrically arranged on axially opposite sides with respect to the equatorial plane.

[0079] In order to increase the structural strength of the tire in the part of the tire in contact with the ground during a cyclist entering a curve and turning and to further contain the weight of the tire, the applicant has observed that it is advantageous for the width of the first juxtaposed region and the second juxtaposed region to generally not be equal to or greater than 22% of the tire width.

[0080] Preferably, the width of each of the first juxtaposed region and the second juxtaposed region is equal to or less than 10% of the tire width.

[0081] Preferably, the width of each of the first juxtaposed region and the second juxtaposed region is equal to or greater than 0.5% of the tire width, more preferably equal to or greater than 2% of the tire width, and even more preferably equal to or greater than 5% of the tire width.

[0082] Preferably, the width of each of the first juxtaposed region and the second juxtaposed region is between 0.5% and 10% of the tire width, more preferably between 2% and 10% of the tire width, and even more preferably between 5% and 10% of the tire width.

[0083] Preferably, the width of the juxtaposed portion of the edge of the carcass ply is equal to or less than 50% of the tire width, more preferably equal to or less than 40% of the tire width.

[0084] Preferably, the width of the juxtaposed portion of the edge of the carcass ply is equal to or greater than 10% of the tire width, more preferably equal to or greater than 20% of the tire width.

[0085] Preferably, the width of the juxtaposed portion of the edge of the carcass ply is between 10% and 50% of the tire width, more preferably between 20% and 40% of the tire width.

[0086] Preferably, the width of the protective layer is equal to, preferably less than, the width of the juxtaposed portion of the edge of the carcass ply.

[0087] Preferably, the juxtaposed portion of the edge of the carcass ply is symmetrically arranged with respect to the equatorial plane.

[0088] Preferably, the first sidewall reinforcing ply is located radially outside the carcass ply.

[0089] Preferably, the second reinforcing ply is located radially outside the carcass ply.

[0090] Preferably, the protective layer is radially arranged between the tread band and the portion of the carcass ply that continuously extends between the first annular anchoring structure and the second annular anchoring structure.

[0091] Preferably, the juxtaposed portion of the edge of the carcass ply is located radially outside the portion of the carcass ply that continuously extends between the first annular anchoring structure and the second annular anchoring structure.

[0092] In the first embodiment, the predetermined order of radial juxtaposition of the first juxtaposed region and the second juxtaposed region is such that the protective layer is preferably radially arranged between the tread band and the juxtaposed portion of the edge of the carcass ply.

[0093] In this embodiment, in the first juxtaposed region, the protective layer is preferably located radially outside the first sidewall reinforcing ply, and in the second juxtaposed region, the protective layer is preferably located radially outside the second sidewall reinforcing ply.

[0094] Alternatively, in this embodiment, in the first juxtaposed region, the protective layer is preferably located radially inside the first sidewall reinforcing ply, and in the second juxtaposed region, the protective layer is preferably located radially inside the second sidewall reinforcing ply.

[0095] In the second embodiment, the predetermined order of radial juxtaposition of the first juxtaposed region and the second juxtaposed region is such that the juxtaposed portion of the edge of the carcass ply is preferably arranged radially between the tread band and the protective layer.

[0096] Preferably, the ratio between the width of the pneumatic tire and the radius of curvature of the inflation profile of the tire at the tread band is between 2.0 and 2.4.

[0097] Preferably, the ratio between the width of the pneumatic tire and the radius of curvature of the inflation profile of the tire at the tread band is between 2.0 and 2.2.

[0098] Preferably, the minimum radius of curvature of the inflation profile of the tire at the tread band is equal to or greater than 95% of the maximum radius of curvature of the inflation profile of the tire at the tread band.

[0099] Preferably, the minimum radius of curvature of the inflation profile of the tire at the tread band is substantially equal to the maximum radius of curvature of the inflation profile of the tire at the tread band.

[0100] In order to minimize the tire weight without compromising the structural stiffness of the tire, the applicant has found it advantageous to provide a smaller thickness in the radial direction of the carcass ply.

[0101] Preferably, the thickness of the carcass ply in the radial direction is less than or equal to 0.50 mm, more preferably less than or equal to 0.45 mm, and even more preferably less than or equal to 0.40 mm.

[0102] Preferably, the thickness of the carcass ply in the radial direction is greater than or equal to 0.10 mm, more preferably greater than or equal to 0.15 mm, and even more preferably greater than or equal to 0.20 mm.

[0103] Preferably, the thickness of the carcass ply in the radial direction is between 0.15 mm and 0.45 mm, more preferably between 0.20 mm and 0.40 mm, for example 0.30 mm.

[0104] In order to allow the tread portion of the tire in contact with the ground during straight running to also have sufficient puncture resistance, while also reducing the weight of the tire, the applicant has found that it is advantageous to make the thickness of the protective layer in the radial direction greater than the thickness of the carcass ply in the radial direction.

[0105] Preferably, the thickness of the protective layer in the radial direction is greater than or equal to 0.25 mm, more preferably greater than or equal to 0.30 mm, and even more preferably greater than or equal to 0.35 mm.

[0106] Preferably, the thickness of the protective layer in the radial direction is less than or equal to 0.55 mm, more preferably less than or equal to 0.50 mm, and even more preferably less than or equal to 0.45 mm.

[0107] Preferably, the thickness of the protective layer in the radial direction is between 0.25 mm and 0.55 mm, more preferably between 0.30 mm and 0.50 mm, for example 0.40 mm.

[0108] In order to minimize the weight of the tire without compromising the structural stiffness of the tire, the applicant has found that it is advantageous to make the thickness of the first sidewall reinforcing ply and the second sidewall reinforcing ply in the radial direction not greater than the thickness of the protective layer in the radial direction.

[0109] Preferably, the thickness of the first sidewall reinforcing ply in the radial direction is greater than or equal to 0.15 mm, more preferably greater than or equal to 0.20 mm, and even more preferably greater than or equal to 0.30 mm.

[0110] Preferably, the thickness of the first sidewall reinforcing ply in the radial direction is less than or equal to 0.55 mm, more preferably less than or equal to 0.50 mm, and even more preferably less than or equal to 0.45 mm.

[0111] Preferably, the thickness of the first sidewall reinforcing ply in the radial direction is between 0.15 mm and 0.55 mm, preferably between 0.30 mm and 0.50 mm, for example 0.40 mm.

[0112] Preferably, the thickness of the second sidewall reinforcing ply in the radial direction is greater than or equal to 0.15 mm, more preferably greater than or equal to 0.20 mm, and even more preferably greater than or equal to 0.30 mm.

[0113] Preferably, the thickness of the second sidewall reinforcing ply in the radial direction is less than or equal to 0.55 mm, more preferably less than or equal to 0.50 mm, and even more preferably less than or equal to 0.45 mm.

[0114] Preferably, the thickness of the second sidewall reinforcing ply in the radial direction is between 0.15 mm and 0.55 mm, preferably between 0.30 mm and 0.50 mm, for example 0.40 mm.

[0115] Preferably, both the first sidewall reinforcing ply and the second sidewall reinforcing ply have the same thickness in the radial direction.

[0116] In order to further improve the structural strength of the tire, the applicant has also found it advantageous to provide multiple reinforcing cords in each layer of the tire.

[0117] Preferably, the carcass ply comprises multiple reinforcing cords that are inclined at a first angle with respect to the equatorial plane, and the first angle is greater than or equal to 25°, preferably greater than or equal to 30°.

[0118] Preferably, the carcass ply comprises multiple reinforcing cords that are inclined at a first angle with respect to the equatorial plane, and the first angle is less than or equal to 70°, more preferably less than or equal to 60°.

[0119] Preferably, the carcass ply comprises multiple reinforcing cords that are inclined at a first angle with respect to the equatorial plane, and the first angle is between 30° and 60°.

[0120] In order to further improve the behavior of the tire in terms of maneuverability, the applicant has also observed that it is advantageous to provide a high number of reinforcing cords in each layer of the tire. The high number of cords also results in a reduced weight (since there are more cords per unit length, which in turn results in less elastomeric material in the layer under consideration and a thinner thickness of the layer) and an improved comfort (since the cords are more flexible).

[0121] Preferably, the number of cords in the carcass ply is greater than or equal to 15 TPI, more preferably greater than or equal to 30 TPI, even more preferably greater than or equal to 60 TPI, even more preferably greater than or equal to 120 TPI.

[0122] Preferably, the number of cords in the carcass ply is less than or equal to 360 TPI, more preferably less than or equal to 300 TPI, even more preferably less than or equal to 240 TPI, even more preferably less than or equal to 200 TPI.

[0123] Preferably, the linear density of the reinforcing cords in the carcass ply is greater than or equal to about 110 dtex, more preferably greater than or equal to about 230 dtex.

[0124] Preferably, the linear density of the reinforcing cords in the carcass ply is less than or equal to about 1300 dtex, more preferably less than or equal to about 940 dtex.

[0125] Preferably, the protective layer comprises a square fabric having weft and warp fabric fibers.

[0126] Preferably, the weft or warp fabric fibers are oriented at an angle of greater than or equal to 25°, preferably greater than or equal to 30°, and even more preferably greater than or equal to 45° with respect to the equatorial plane.

[0127] Preferably, the inflation pressure of the tire is greater than or equal to 3.5 bar, more preferably greater than or equal to 4 bar, and even more preferably greater than or equal to 5 bar.

[0128] Preferably, the weight of the tire is less than 400 g, preferably less than 350 g, and even more preferably less than 250 g. Description of the Drawings

[0129] Further features and advantages of the tire of the present invention will become more apparent from the following detailed description of some preferred embodiments of the invention with reference to the accompanying drawings. In these drawings:

[0130] - Figure 1 is a schematic perspective view of a tire according to the present invention, with some components removed to better highlight other components;

[0131] - Figure 2 is a schematic axial cross-sectional view of a tire according to the present invention;

[0132] - Figures 3 to 6 shows a possible schematic configuration representing an alternative embodiment of a tire according to the present invention. Detailed Description of the Preferred Embodiments

[0133] In Figure 1 and Figure 2 the reference numeral 100 generally designates a tire for a bicycle wheel according to the present invention. In particular, it relates to a tire intended to be mounted on a racing bicycle wheel.

[0134] In the tire 100 an equatorial plane X ( Figure 2 ) and a rotational axis (not shown) perpendicular to the equatorial plane X are defined. An axial (or transverse, or lateral) direction parallel to the rotational axis and a circumferential (or longitudinal) direction parallel to the equatorial plane X and corresponding to the rolling direction of the tire 100 are also defined.

[0135] Once inflated, the tire 100 has a generally toroidal shape.

[0136] The inflation pressure of the tire mounted on the corresponding rim is greater than or equal to about 3.5 bar, more preferably greater than or equal to about 4 bar, and even more preferably greater than or equal to about 5 bar.

[0137] The tire 100 includes a carcass structure 2 (single ply tire) having a single carcass ply 3.

[0138] The carcass ply 3 is turned up around a first annular anchoring structure 4a and a second annular anchoring structure 4b (commonly referred to as the "bead core").

[0139] The first annular anchoring structure 4a and the second annular anchoring structure 4b are preferably made of textile fibers having a high elastic modulus, such as, for example, aramid fibers (the generic name for aromatic polyamide fibers), in order to make a so-called "foldable" tire. Alternatively, the first annular anchoring structure 4a and the second annular anchoring structure 4b may be made of wire (such as, for example, steel).

[0140] A tread band 6 is provided in a radially outer position relative to the carcass structure 2, and the tire 100 contacts the road surface through the tread band.

[0141] The tread band 6 is made of a composite of an elastomeric material, which preferably includes at least one elastomeric diene polymer.

[0142] The tread band 6 includes a central portion 7 and two lateral portions 8 (or sidewalls 8), which are arranged on axially opposite sides relative to the central portion 7.

[0143] Preferably, the width of the tread band is equal to or less than 50% of the tire width, more preferably equal to or less than 45% of the tire width.

[0144] Preferably, the width of the tread band is equal to or greater than 30% of the tire width, more preferably equal to or greater than 35% of the tire width.

[0145] The width of the tread band is between 30% and 50% of the tire width, for example about 40% of the tire width.

[0146] The carcass ply 3 is turned up around the first annular anchoring structure 4a and the second annular anchoring structure 4b such that two layers of the carcass ply 3 are arranged at two opposite first portions 9 of the tire, and the two opposite first portions are preferably at least partially juxtaposed on the sidewalls 8 of the tread band 6. The carcass ply 3 also has three layers of the ply juxtaposed at a second portion 10 of the tire 100, and the second portion is axially arranged between the two first portions 9 and preferably at least partially coincides with the central portion 7 of the tread band 8.

[0147] The carcass ply 3 includes two free edges 11 that are radially juxtaposed on top of each other at juxtaposed portions 12 at the edges of the carcass ply. Each free edge 11 includes an end edge 13 that separates the portion of the carcass ply 3 having three juxtaposed layers of the ply from the portion having two juxtaposed layers of the ply.

[0148] The two free edges 11 are located radially outside a portion 3a of the carcass ply 3, said portion extending continuously between a first annular anchoring structure 4a and a second annular anchoring structure 4b.

[0149] As shown in the drawings, three juxtaposed layers of the cited ply are defined by a portion 3a of the carcass ply 3 extending continuously between a first annular anchoring structure 4a and a second annular anchoring structure 4b and two free edges 11 juxtaposed radially on top of one another. Two juxtaposed layers of the cited ply are defined by a portion 3a of the carcass ply 3 extending continuously between a first annular anchoring structure 4a and a second annular anchoring structure 4b and a portion 3b of the carcass ply 3 extending between the respective radially juxtaposed free edges 11 and the respective annular anchoring structures 4a, 4b.

[0150] The juxtaposed portions 12 of the edges of the carcass ply are symmetrically arranged with respect to the equatorial plane X, in other words, the equatorial plane X ideally divides the juxtaposed portions 12 of the edges of the carcass ply into two half-portions of equal width.

[0151] The width of the juxtaposed portions 12 of the edges of the carcass ply is equal to or less than 50% of the tyre width, more preferably equal to or less than 40% of the tyre width.

[0152] The width of the juxtaposed portions of the edges of the carcass ply is equal to or greater than 20% and equal to or less than 40% of the tyre width.

[0153] The width of the juxtaposed portions 12 of the edges of the carcass ply is less than the width of the tread band 6.

[0154] The thickness of the carcass ply 3 in the radial direction is less than 0.50 mm and greater than 0.20 mm.

[0155] For example, the thickness of the carcass ply 3 in the radial direction is 0.30 mm.

[0156] The carcass ply 3 is preferably made of an elastomeric material and comprises a plurality of reinforcing cords 30 arranged substantially parallel to one another. For the sake of clarity of illustration, Figure 1 the reference numeral 30 in the drawings is associated with all the reinforcing cords shown.

[0157] The reinforcing cords 30 are preferably made of a textile material selected from nylon, rayon, PET, PEN, lyocell, aramid and are made of one or more ends, preferably 1 or 2 ends.

[0158] The diameter of the reinforcing cords 30 is preferably between 0.10 mm and 0.45 mm, more preferably between 0.12 mm and 0.35 mm, for example equal to 0.15 mm.

[0159] The linear density of the reinforcing cord 30 is between 110 dtex and 940 dtex, for example equal to 470 dtex.

[0160] Specific examples of the fabric material that can be used for the above-mentioned reinforcing cord 30 are as follows:

[0161] Nylon 930 dtex / 1

[0162] Nylon 470 dtex / 1

[0163] Nylon 230 dtex / 1

[0164] Rayon 930 dtex / 1

[0165] Rayon 470 dtex / 1

[0166] Rayon 230 dtex / 1

[0167] Aramid 470 / 1

[0168] The number 1 after dtex represents the number of pieces.

[0169] The reinforcing cord 30 is inclined at an angle between approximately 30° and approximately 60° with respect to the equatorial plane of the tire 100.

[0170] The number of plies of the carcass ply 3 is preferably between 30 TPI and 300 TPI, for example equal to 240 TPI.

[0171] On the outer peripheral edges of the first annular anchoring structure 4a and the second annular anchoring structure 4b, corresponding tapered elastomeric fillers can be applied, and the tapered elastomeric fillers occupy the spaces defined between the carcass ply 3 and the first annular anchoring structure 4a and between the carcass ply 3 and the second annular anchoring structure 4b.

[0172] The area of the tire including the first annular anchoring structure 4a or the second annular anchoring structure 4b and the possible elastomeric fillers forms the so-called "bead", which is Figure 1 designated as 5 as a whole and is intended to anchor the tire to the corresponding mounting rim (not shown) by elastic forced fitting.

[0173] At the first annular anchoring structure 4a and the second annular anchoring structure 4b, reinforcing belt elements 20 can be applied, such as Figure 4 and Figure 6As shown. When the tire is mounted on the wheel rim, this reinforcing belt element 20 is radially arranged between the carcass ply 3 and this rim. The reinforcing belt element 20 has a limited axial extension, which is preferably between 2% and 15% of the width of the tire 100. The purpose of the reinforcing belt element 20 is to allow attachment and friction with the rim and also avoid damage that may be caused by wear due to friction between the carcass ply 3 and the rim. The reinforcing belt element 20 is also referred to as a "bead filler".

[0174] In a radially outer position relative to the aforementioned carcass structure 2, a first sidewall reinforcing ply 14 and a second sidewall reinforcing ply 15 are provided.

[0175] The first sidewall reinforcing ply 14 is axially arranged between the first annular anchoring structure 4a and the equatorial plane X of the tire, and the second sidewall reinforcing ply 15 is axially arranged between the second annular anchoring structure 4b and the equatorial plane X.

[0176] The first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 do not reach the equatorial plane X and are axially spaced apart from each other.

[0177] The first sidewall reinforcing ply 14 extends from the first annular anchoring structure 4a towards the equatorial plane X without turning around the first annular anchoring structure 4a.

[0178] The second sidewall reinforcing ply 15 extends from the second annular anchoring structure 4b towards the equatorial plane X without turning around the second annular anchoring structure 4b.

[0179] The width of the first sidewall reinforcing ply 14 is preferably between 30% and 47% of the tire width.

[0180] The width of the second sidewall reinforcing ply 15 is preferably between 30% and 47% of the tire width.

[0181] The first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 have the same width.

[0182] The tread band 6 is at least radially juxtaposed on the respective axial inner end edges 14a, 15a of the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15.

[0183] The axial distance D1 ( Figure 3 ) between the end edges 14a, 15a of the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 that are proximal to the equatorial plane is equal to or greater than 6% of the width of the tire 100, preferably between 6% and 20% of the width of the tire 100.

[0184] The first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 are radially juxtaposed on the juxtaposed portion 12 of the edge of the carcass ply at least at the corresponding end edges 14a, 15a.

[0185] In a preferred embodiment of the present invention, the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 are radially juxtaposed on the juxtaposed portion 12 of the edge of the carcass ply in corresponding portions having a width equal to or less than 10% of the width of the tire 100.

[0186] The first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 have a thickness in the radial direction between 0.30 mm and 0.50 mm.

[0187] For example, the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 have a thickness of 0.40 mm in the radial direction.

[0188] The first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 have equal thicknesses in the radial direction.

[0189] Both the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 are made of an elastomeric material and include a plurality of reinforcing cords 31.

[0190] For the sake of clarity of illustration, Figure 1 the reference numeral 31 in is associated with all the reinforcing cords shown with respect to the second sidewall reinforcing ply 15.

[0191] The reinforcing cords 31 are preferably made of a textile material selected from nylon, rayon, PET, PEN, lyocell, aramid, in one or more ends, preferably in 1 or 2 ends.

[0192] The diameter of the reinforcing cords 31 is preferably between 0.10 mm and 0.45 mm, more preferably between 0.12 mm and 0.35 mm, for example equal to 0.30 mm.

[0193] The linear density of the reinforcing cords 31 is between 230 dtex and 940 dtex, for example equal to 450 dtex.

[0194] Specific examples of the textile materials that can be used for the above-mentioned reinforcing cords 31 are as follows:

[0195] Nylon 930 dtex / 1

[0196] Nylon 470 dtex / 1

[0197] Nylon 230 dtex / 1

[0198] Rayon 930 dtex / 1

[0199] Viscose rayon 470 dtex / 1

[0200] Viscose rayon 230 dtex / 1

[0201] Aramid 470 / 1

[0202] The number 1 after dtex indicates the number of ends.

[0203] The reinforcing cord 31 can be inclined at an angle between about 30° and about 60° with respect to the equatorial plane of the tire 100.

[0204] Alternatively, the reinforcing cord 31 can be made into a square fabric structure (i.e., having warp reinforcing cords and weft reinforcing cords). The cords 31 in the weft and warp directions are oriented at an angle of 45° with respect to the equatorial plane.

[0205] The number of cords of the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 is preferably between 30 TPI and 240 TPI, more preferably between 120 TPI and 200 TPI, for example equal to 60 TPI.

[0206] The protective layer 16 is radially interposed between the tread band 6 and the portion 3a of the carcass ply 3 that continuously extends between the first annular anchoring structure 4a and the second annular anchoring structure 4b.

[0207] The protective layer 16 can serve as a protective layer to improve the puncture resistance of the tire 100.

[0208] The protective layer 16 is axially interposed between the first annular anchoring structure 4a and the second annular anchoring structure 4b and does not reach the first annular anchoring structure 4a and the second annular anchoring structure 4b.

[0209] The protective layer 16 is symmetric with respect to the equatorial plane X and its width is between 20% and 45% of the width of the tire 100.

[0210] The width of the protective layer 16 is less than the width of the tread band 6.

[0211] The width of the protective layer 16 can be substantially equal to the width of the juxtaposed portion 12 of the edges of the carcass ply.

[0212] The thickness of the protective layer 16 in the radial direction is between 0.30 mm and 0.50 mm.

[0213] For example, the thickness of the protective layer 16 in the radial direction is 0.40 mm.

[0214] The protective layer 16 is made of an elastomeric material and includes a plurality of reinforcing cords 32.

[0215] For the sake of clarity of illustration, Figure 1Reference numeral 32 in the figures is associated with all of the reinforcing cords.

[0216] The reinforcing cord 32 is preferably made of a fabric material selected from nylon, rayon, PET, PEN, lyocell, and aramid, made with one or more ends, preferably made with 1 or 2 ends.

[0217] The diameter of the reinforcing cord 32 is preferably between 0.10 mm and 0.45 mm, more preferably between 0.12 mm and 0.35 mm, for example equal to 0.30 mm.

[0218] The linear density of the reinforcing cord 32 is between 230 dtex and 940 dtex, for example equal to 450 dtex.

[0219] Specific examples of the fabric materials that can be used for the above-mentioned reinforcing cord 31 are as follows:

[0220] Nylon 930 dtex / 1

[0221] Nylon 470 dtex / 1

[0222] Nylon 230 dtex / 1

[0223] Rayon 930 dtex / 1

[0224] Rayon 470 dtex / 1

[0225] Rayon 230 dtex / 1

[0226] Aramid 470 / 1

[0227] The number 1 after dtex indicates the number of ends.

[0228] The reinforcing cord 32 is made into a square fabric structure (i.e., having warp reinforcing cords and weft reinforcing cords). The cords 32 in the weft and warp directions are oriented at an angle equal to or greater than 45° with respect to the equatorial plane.

[0229] The number of threads of the protective layer 16 is preferably between 30 TPI and 240 TPI, more preferably between 120 TPI and 200 TPI, for example equal to 60 TPI.

[0230] As Figure 3 and Figure 4 Schematically shown, the protective layer 16 can be radially arranged between the tread band 6 and the juxtaposed portion 12 of the edge of the carcass ply.

[0231] In this case, the protective layer 16 can be arranged in one of the following two configurations:

[0232] As Figure 3 and 4As shown, the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15 are located radially outside, or are located radially inside with respect to the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15.

[0233] Alternatively, as Figure 5 and Figure 6 shown, the juxtaposed portion 12 of the edge of the carcass ply can be radially interposed between the tread band 6 and the protective layer 16.

[0234] In any case, a first juxtaposed region 17 and a second juxtaposed region 18 are defined in the tire 100, wherein the protective layer 16, the first sidewall reinforcing ply 14 and the juxtaposed portion 12 of the edge of the carcass ply are radially juxtaposed on top of each other, and wherein the protective layer 16, the second sidewall reinforcing ply 15 and the juxtaposed portion 12 of the edge of the carcass ply are radially juxtaposed on top of each other.

[0235] The first juxtaposed region 17 and the second juxtaposed region 18 are symmetric with respect to the equatorial plane X and are axially spaced from the equatorial plane X by a distance between 6% and 24% of the width of the tire 100.

[0236] The width of each of the first juxtaposed region 17 and the second juxtaposed region 18 is equal to or greater than 0.5% of the width of the tire 100 and equal to or less than 10% of the width of the tire 100.

[0237] In any case, the tread band 6 is radially arranged outside the first juxtaposed region 17 and the second juxtaposed region 18. The tread band 6 is radially juxtaposed on the first juxtaposed region 17 and the second juxtaposed region 18.

[0238] As Figures 3 to 6 schematically shown, at the first juxtaposed region 17 and the second juxtaposed region 18, the tire 100 has five mutually radially overlapping plies. In the first juxtaposed region 17, these five plies are composed of the portion 3a (1 ply) of the carcass ply 3 continuously extending between the first annular anchoring structure 4a and the second annular anchoring structure 4b, the juxtaposed portion 12 of the edge of the carcass ply (2 plies), the first sidewall reinforcing ply 14 (1 ply) and the protective layer 16 (1 ply). In the second juxtaposed region 18, these five plies are composed of the portion 3a (1 ply) of the carcass ply 3 continuously extending between the first annular anchoring structure 4a and the second annular anchoring structure 4b, the juxtaposed portion 12 of the edge of the carcass ply (2 plies), the second sidewall reinforcing ply 15 (1 ply) and the protective layer 16 (1 ply).

[0239] As Figures 3 to 6As schematically shown, in the axial space between the first juxtaposition region 17 and the second juxtaposition region 18, the tire 100 has four radially overlapping ply layers. These four ply layers are constituted by the portion 3a (one ply layer) of the carcass ply 3 that continuously extends between the first annular anchoring structure 4a and the second annular anchoring structure 4b, the juxtaposed portions 12 (two ply layers) of the edges of the carcass ply, and the protective ply 16 (one ply layer).

[0240] As Figures 3 to 6 As schematically shown, in the axial space between the first juxtaposition region 17 and the first annular anchoring structure 4a, the tire 100 has (excluding possible reinforcing belt elements 20) three radially juxtaposed ply layers. These three ply layers are constituted by the portion 3a (one ply layer) of the carcass ply 3 that continuously extends between the first annular anchoring structure 4a and the second annular anchoring structure 4b, the portion 3b (one ply layer) of the carcass ply 3 that extends between the radially juxtaposed free edges 11 and the first annular anchoring structure 4a, and the first sidewall reinforcing ply 14 (one ply layer).

[0241] As Figures 3 to 6 As schematically shown, in the axial space between the second juxtaposition region 18 and the second annular anchoring structure 4b, the tire 100 has (excluding possible reinforcing belt elements 20) three radially juxtaposed ply layers. These three ply layers are constituted by the portion 3a (one ply layer) of the carcass ply 3 that continuously extends between the first annular anchoring structure 4a and the second annular anchoring structure 4b, the portion 3b (one ply layer) of the carcass ply 3 that extends between the radially juxtaposed free edges 11 and the second annular anchoring structure 4b, and the second sidewall reinforcing ply 15 (one ply layer).

[0242] The first juxtaposition region 17 and the second juxtaposition region 18 are preferably axially arranged at a portion of the tread band 6 that does not contact the ground during straight running.

[0243] As Figure 1 As schematically shown, the ratio between the width L of the pneumatic tire and the radius of curvature R of the pneumatic contour of the tire at any point of the tread band 6 (preferably at any point of the central portion 7 of the tread band 6) is greater than 2.0.

[0244] The ratio between the width L of the pneumatic tire and the radius of curvature R of the pneumatic contour of the tire at any point of the tread band 6 (preferably at any point of the central portion 7 of the tread band 6) is less than 2.2.

[0245] The radius of curvature R of the pneumatic contour of the tire along the width of the tread band 6 can be different at different points of the tread band.

[0246] The minimum radius of curvature R of the inflation profile of the tire at the tread band 6 (preferably at the central part 7 of the tread band 6) is equal to or greater than 95% of the maximum radius of curvature R of the inflation profile of the tire at the tread band 6 (preferably at the central part 7 of the tread band 6).

[0247] The tire 100 has a mounting diameter according to ISO or ETRTO conventions, which is preferably equal to 622 mm or equal to 630 mm.

[0248] The weight of the tire is less than 400 grams, preferably less than or equal to 350 grams.

[0249] The arrangement and disposition of the first juxtaposed region 17 and the second juxtaposed region 18 provide increased structural stiffness to the portion of the tire 100 that contacts the ground during a cyclist's entry into and turning in a curve, thereby improving the accuracy of the turning trajectory and the resistance to lateral thrust, and enabling a radius of curvature of the inflation profile of the tire 100 to be obtained that is constant, or substantially constant, or in any case very similar between the portion of the tire that contacts the ground during straight-line travel and during turning, thereby greatly enhancing the cyclist's comfort and the sense of safety and maneuverability.

[0250] The Applicant has also surprisingly noted that the arrangement and disposition of the first juxtaposed region 17 and the second juxtaposed region 18 improve the rolling resistance of the tire and reduce this rolling resistance.

[0251] A number of tests were carried out to evaluate the performance of the racing bicycle tire according to the present invention.

[0252] In particular, two tires were tested: a reference tire (tire 1) and a tire according to the present invention (tire 2).

[0253] Both tires were of size 28 - 622 (ETRTO).

[0254] Both tires were tubeless ready (TLR).

[0255] Both tires were mounted on the same rim. The stiffness of the rim was such that the contribution of the rim to the overall deformation of the wheel was less than 1% when any load was applied to the wheel.

[0256] The two tires differed only in the following characteristics:

[0257] - The reference tire did not include the first sidewall reinforcing ply 14 and the second sidewall reinforcing ply 15, but instead included a single reinforcing ply extending from bead core to bead core.

[0258] - The ratio between the width of the inflated tire of the reference tire and the radius of curvature at any point of the inflation profile of the tire was 1.96.

[0259] - The tire according to the present invention has a first juxtaposed region 17 and a second juxtaposed region 18, which are respectively arranged at positions 5% of the tire width away from the equatorial plane X. The widths of both the first juxtaposed region 17 and the second juxtaposed region 18 are 8% of the tire width.

[0260] - The ratio between the width of the inflated tire according to the present invention and the radius of curvature at any point of the inflated profile of the tire in the tread band is 2.05.

[0261] - The tire according to the present invention has a reinforcing layer 16.

[0262] - The weight of tire 2 is reduced by 9% relative to the weight of tire 1.

[0263] Both tires are equipped with the same carcass structure, the same tread band, and the same reinforcing belt elements.

[0264] For the rolling resistance test of the tires, each wheel (rim and tire inflated to 5.7 bar) is mounted on top of a rotating drum with a diameter of 77 cm, and a load of 416 N is applied. The drum rotates at a speed of 200 revolutions per minute (corresponding to approximately 28.8 Km / h). After the drum starts rotating for 30 minutes, the driving torque required to keep the drum rotating is detected three times, with an interval of 20 seconds each time, and the average value of the three detections is calculated. The difference between the average values calculated for tire 1 and tire 2 is interpreted as the difference in rolling resistance between the two tires.

[0265] The test shows that the rolling resistance of tire 2 is approximately 8% lower than that of tire 1.

[0266] For the ride performance test, the racing bicycle is alternately equipped with the above-mentioned type 1 and type 2 tires. The inflation pressure of the tires is approximately 5.7 bar. The tester rides the bicycle on a route that alternately includes uphill, downhill, flat sections, fast sections, slow sections, reverse slope curves, and sharp curves.

[0267] The following table summarizes the feelings felt by the tester, where the term "smoothness" represents the felt rolling resistance, the term "straight comfort" represents the riding comfort felt by the tester during driving along a straight section, the term "support the first turning step" represents the ability to maintain a set trajectory during the start of the turning step, the term "support the second turning step" represents the ability to maintain a set trajectory during leaning in a curve, the term "sense of security" represents the gradualness of the turning behavior (which basically corresponds to the combination of the values of "support the first turning step" and "support the second turning step"), and the term "reactivity" represents the speed of transmitting the driving torque to the ground.

[0268] Each symbol "+" represents an approximate 5% improvement in the behavior of a bicycle equipped with type 1 tires relative to a reference.

[0269] Tire 2 Ride comfort ++ Straight-line comfort +++++ Support the first turning step ++++ Support the second turning step +++++ Sense of security ++++ Responsiveness ++

[0270] The present invention has been described with reference to some preferred embodiments. Various modifications may be made to the above embodiments, which still remain within the scope of protection of the present invention as defined by the following claims.

Claims

1. A tire (100) for a racing bicycle wheel, the tire comprising a carcass structure (2) and a tread band (6) arranged in a radially outer position relative to the carcass structure (2); wherein, the carcass structure (2) comprises a single carcass ply (3) that is turned around a first annular anchoring structure (4a) and a second annular anchoring structure (4b), and wherein the free edges (11) of the carcass ply (3) are radially juxtaposed on top of each other at the juxtaposed portion (12) of the edges of the carcass ply; a protective layer (16), the width of the protective layer being equal to or less than 50% of the width of the tire (100); a first sidewall reinforcing ply (14) axially arranged between the first annular anchoring structure (4a) and the equatorial plane (X) of the tire; a second sidewall reinforcing ply (15) axially arranged between the second annular anchoring structure (4b) and the equatorial plane (X); wherein, in a first juxtaposed area (17), the protective layer (16), the first sidewall reinforcing ply (14) and the juxtaposed portion (12) of the edges of the carcass ply are radially juxtaposed in a predetermined order; wherein, in a second juxtaposed area (18), the protective layer (16), the second sidewall reinforcing ply (15) and the juxtaposed portion (12) of the edges of the carcass ply are radially juxtaposed in a predetermined order; wherein the first juxtaposed area (17) and the second juxtaposed area (18) are arranged on axially opposite sides relative to the equatorial plane (X) and the respective distances from the equatorial plane (X) are between 3% and 24% of the width of the tire (100).

2. The tire (100) according to claim 1, wherein, the first juxtaposed area (17) and the second juxtaposed area (18) are arranged on axially opposite sides relative to the equatorial plane (X) and the respective distances from the equatorial plane (X) are between 5% and 20% of the width of the tire (100).

3. The tire (100) according to claim 1 or 2, wherein, the first juxtaposed area (17) and the second juxtaposed area (18) are symmetrically arranged on axially opposite sides relative to the equatorial plane (X).

4. The tire (100) according to any one of the preceding claims, wherein, the widths of the first juxtaposed area (17) and the second juxtaposed area (18) are each equal to or less than 22% of the width of the tire (100), preferably equal to or less than 10% of the width of the tire (100).

5. The tire (100) according to any one of the preceding claims, wherein, the widths of the first juxtaposed area (17) and the second juxtaposed area (18) are each equal to or greater than 0.5% of the width of the tire, more preferably equal to or greater than 2% of the width of the tire, and even more preferably equal to or greater than 5% of the width of the tire.

6. The tire (100) according to any one of the preceding claims, wherein, the width of the juxtaposed portion (12) of the edge of the carcass ply is between 10% and 50% of the width of the tire (100), preferably between 20% and 40%.

7. The tire (100) according to any one of the preceding claims, wherein, the juxtaposed portion (12) of the edge of the carcass ply is symmetrically arranged with respect to the equatorial plane (X).

8. The tire (100) according to any one of the preceding claims, wherein, the protective layer (16) is symmetrically arranged with respect to the equatorial plane (X).

9. The tire (100) according to any one of the preceding claims, wherein, the first sidewall reinforcing ply (14) and the second sidewall reinforcing ply (15) are located radially outside the carcass ply (3).

10. The tire (100) according to any one of the preceding claims, wherein, the protective layer (16) is radially arranged between the tread band (6) and the portion (3a) of the carcass ply that continuously extends between the first annular anchoring structure (4a) and the second annular anchoring structure (4b).

11. The tire (100) according to claim 10, wherein, the protective layer (16) is radially arranged between the tread band (6) and the juxtaposed portion (12) of the edge of the carcass ply.

12. The tire (100) according to claim 10, wherein, the juxtaposed portion (12) of the edge of the carcass ply is radially arranged between the tread band (6) and the protective layer (16).

13. The tire (100) according to any one of the preceding claims, wherein, the width of the tread band (6) is at least equal to the width of the protective layer (16).

14. The tire (100) according to any one of the preceding claims, wherein, the thickness of the reinforcing layer (16) in the radial direction is between 0.25 mm and 0.55 mm.

15. The tire (100) according to any one of the preceding claims, wherein, the respective thicknesses of the first sidewall reinforcing ply (14) and the second sidewall reinforcing ply (15) in the radial direction are between 0.15 mm and 0.55 mm.

16. The tire (100) according to any one of the preceding claims, wherein, the carcass ply (3) includes a plurality of reinforcing cords (30), and the plurality of reinforcing cords are inclined at a first angle with respect to the equatorial plane, and the first angle is between about 30° and about 60°.

17. The tire (100) according to any one of the preceding claims, wherein, the reinforcing layer (16) includes a square fabric having reinforcing cords (32) in the weft or warp direction, and the reinforcing cords are oriented at an angle greater than 25°, more preferably greater than 30°, and even more preferably greater than 45° with respect to the equatorial plane.

18. The tire (100) according to any one of the preceding claims, wherein, the inflation pressure of the tire (100) is greater than 3.5 bar.

19. The tire (100) according to any one of the preceding claims, wherein, the weight of the tire (100) is equal to or less than about 400 g, preferably equal to or less than about 350 g.

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