Motorcycle tire

Abstract

Describes a tire (1) for a motorcycle wheel, which includes a tread band (8) of the "crown base" type, the tread band including: a radially outer portion formed by a central sub-portion (11a) made of a first vulcanized elastomeric material and a pair of lateral sub-portions (11b, 11c) made of a second vulcanized elastomeric material; and a radially inner portion (12) made of a third vulcanized elastomeric material. The dynamic elastic modulus (E') of the first vulcanized elastomeric material of the central sub-portion (11a) measured at a frequency of 10 Hz and a temperature of 23 °C is greater than the dynamic elastic modulus (E') of the second vulcanized elastomeric material of the lateral sub-portions (11b, 11c) measured under the same conditions, and the corresponding dynamic elastic moduli (E') of these two vulcanized elastomeric materials measured at the same frequency of 10 Hz and a temperature of 23 °C are between 5.2 MPa and 6.5 MPa and greater than the dynamic elastic modulus (E') of the third vulcanized elastomeric material measured under the same conditions. In the tire (1), the ratios R1 and R2 between the dynamic elastic modulus and tanδ of the second vulcanized elastomeric material of the lateral sub-portions (11b, 11c) of the radially outer portion of the tread band (8) measured at a frequency of 10 Hz and a temperature of 100 °C and the dynamic elastic modulus and tanδ of the third vulcanized elastomeric material of the radially inner portion (12) measured at a frequency of 10 Hz and a temperature of 70 °C are between 0.8 and 1.2.

Description

TECHNICAL FIELD

[0001] The present invention relates to a motorcycle tire.

[0002] In particular, the present invention relates to a motorcycle tire for "super sport" and / or "hyper sport" motorcycles having a large displacement (e.g., 600 cm 3 or 1000 cm 3 or greater) and / or high power (e.g., 200 hp or greater), such motorcycles also being used on race tracks.

[0003] More particularly, the present invention relates to a high-performance tire intended to be mounted on the rear wheel of a motorcycle, in other words, a tire capable of maintaining a maximum speed of at least about 210 km / h or withstanding a maximum load of at least about 210 kg or both. BACKGROUND ART

[0004] For example, motorcycle tires are known from EP 2 662 226 A1 and WO 2019 / 082012. SUMMARY OF THE INVENTION

[0005] Recently, it has been observed that there is a trend on the market to introduce high-power motorcycles for super sport or hyper sport use. Indeed, there are road motorcycles on the market with a displacement of 1000 cm 3 and greater and a power of 200 hp or even greater.

[0006] The applicant has noted that the demand for such super sport motorcycles is increasing both on the road and on the race track.

[0007] At the same time, the applicant has noted that there is also an increasing demand for high-performance tires that are suitable for both high-demand sporty riding (e.g., completed on a race track) and for the service life and handling in any atmospheric and seasonal conditions (the motorcycle is suitable for year-round use on the road).

[0008] In this regard, the applicant has particularly noted the recent trend that users expect the tires mounted on super sport motorcycles to have both the handling and performance under extreme speed and handling conditions on dry and / or hot ground (hereinafter also referred to as "hot" use conditions) and the handling and grip under wet and / or cold climatic conditions or non-optimal road surface conditions (hereinafter also referred to as "cold" use conditions), and to maintain the tire performance as stable as possible over time.

[0009] Meeting these conflicting requirements with a single pair of tires is a particularly difficult task, because usually different interventions are required for each of the above requirements, using solutions suitable for a particular problem but conflicting with other problems.

[0010] To improve the handling and performance on dry and / or hot ground as well as in wet and / or cold climatic conditions or on non-optimal road surfaces, it is particularly necessary to ensure optimal grip under these different driving conditions.

[0011] To improve the grip of a tire, when manufacturing the tread band, so-called soft vulcanized elastomeric materials (also defined herein as the term "rubber compound") can be used, which can better adapt to the roughness of the road surface by mimicking the irregular profile of the road surface. These vulcanized elastomeric materials typically have the characteristics of low elastic modulus and / or high hysteresis.

[0012] However, the applicant has found that overly soft rubber compounds can lead to a decrease in driving stability when traveling in a straight line and can shorten the life of the tire.

[0013] To overcome the above problems, tires having tread bands made of different rubber compounds have been proposed. Typically, the rubber compound at the shoulders is softer, while the rubber compound at the crown is less soft.

[0014] For example, tires configured in this way are described in EP 2 662 226.

[0015] However, regarding this configuration of the tread band, the applicant has observed that the handling and performance of the tire tend to decrease under "hot" usage conditions, especially in extreme usage cases (such as, for example, on a race track), thus seriously impairing the service life of the tire.

[0016] To attempt to meet the aforementioned conflicting requirements with a single pair of tires, tires having tread bands made of different rubber compounds have also been proposed, typically using rubber compounds with a higher carbon black filler content at the shoulder portions, while using several rubber compounds with a higher white filler content at the crown and at the intermediate annular portion of the tread band, all in combination with an appropriate distribution and positioning of the grooves of the tread band at the interfaces between the rubber compounds of different compositions, as described, for example, in the applicant's patent application WO 2019 / 082012.

[0017] Finally, the applicant has noted that a rigid tire structure (typically used for race tracks) does not seem to be very suitable for road use. On a race track, the deflated pressure of the tire is a few tenths of a bar lower than the pressure recommended by the manufacturer to have a larger ground contact area and thus be able to be well-prepared for extreme handling, but on the road, the tire needs to be inflated to the pressure recommended by the manufacturer to provide comfort, grip, and the ability to absorb stresses on different road surfaces.

[0018] In the process of seeking continuous improvement of motorcycle tires, the applicant has twofold objectives: to improve and maintain for as long as possible the handling and tire performance under "hot" usage conditions, while not compromising the handling and grip performance of the tire under the above-mentioned "cold" usage conditions.

[0019] The applicant has found that by adopting a so-called "crown base" tread band structure and by using a vulcanized elastomeric material having suitable dynamic mechanical properties under both "cold" and "hot" usage conditions of the tire, such twofold objectives can be achieved.

[0020] In particular, the applicant has found that for this purpose, the following provisions must be adopted simultaneously:

[0021] i) Use a construction of the radially outer part of the tread band of the following type, which construction includes a central sub-part arranged across the equatorial plane of the tire and a pair of lateral sub-parts located distally with respect to the equatorial plane of the tire and arranged on opposite sides of the central sub-part; and

[0022] ii) Use a vulcanized elastomeric material having specific dynamic mechanical characteristics under the respective "hot" and "cold" usage conditions of the tire in each part of the tread band.

[0023] In this regard, the applicant has also found that it is necessary to differentially evaluate the dynamic mechanical characteristics of the vulcanized elastomeric materials used to manufacture different parts of the tread band for each elastomeric material and under specific stress and temperature conditions, which stress and temperature conditions can be associated with the actual usage conditions of each material, and each material will be subjected to different types of stress and different temperatures during tire usage, depending on the position of the material in the tread band.

[0024] Regarding the "cold" usage of the tire, the applicant has particularly found that the dynamic mechanical characteristics predicting the behavior of the tire under such usage conditions are the dynamic elastic modulus E' and tanδ measured at a frequency of 10 Hz and a temperature of 23 °C for all elastomeric materials forming the tread band.

[0025] On the contrary, regarding the "hot" usage of the tire, the applicant has found that the dynamic mechanical characteristics predicting the behavior of the tire under such usage conditions are the dynamic elastic modulus E' and tanδ measured respectively under the following conditions:

[0026] - Measuring the vulcanized elastomeric materials of the central sub-part of the radially outer part of the tread band and the vulcanized elastomeric materials of the radially inner part of the tread band at a frequency of 10 Hz and a temperature of 70 °C; and

[0027] - Measuring the vulcanized elastomeric materials of the lateral sub-parts of the radially outer part of the tread band at a frequency of 10 Hz and a temperature of 100 °C.

[0028] Accordingly, the Applicant has found that it is possible to achieve the maintenance of the handling and grip performance of the tyre under the above-mentioned "cold" usage conditions by using the following materials:

[0029] - In the central sub-part of the outer radial part of the tread band, use a first vulcanized elastomeric material whose dynamic elastic modulus E' measured at a frequency of 10 Hz and a temperature of 23 °C is greater than the dynamic elastic modulus E' of a second vulcanized elastomeric material used in the lateral sub-part of the outer radial part of the tread band, and

[0030] - In the inner radial part of the tread band, use a third vulcanized elastomeric material whose dynamic elastic modulus E' measured at a frequency of 10 Hz and a temperature of 23 °C is less than the dynamic elastic moduli E' of the aforementioned first and second elastomeric materials.

[0031] On the other hand, with regard to the "hot" usage of the tyre, the Applicant has found that the desired objectives of improving the handling and performance of the tyre and maintaining the handling and performance constant for as long as possible can be achieved simultaneously by:

[0032] - Keeping the ratio between the "hot" dynamic elastic modulus (E') of the second vulcanized elastomeric material used in the lateral sub-part of the outer radial part of the tread band and the "hot" dynamic elastic modulus (E') of the third vulcanized elastomeric material used in the inner radial part of the tread band at a value close to 1, i.e., keeping the dynamic elastic moduli (E') of these materials at very similar values to each other; and

[0033] - Keeping the ratio between the "hot" tanδ of the second and third vulcanized elastomeric materials and the ratio between the "hot" tanδ of the first and third vulcanized elastomeric materials at values close to 1, i.e., keeping the tanδ of these materials at very similar values to each other.

[0034] The Applicant has surprisingly found that by controlling the modulus and hysteresis values, in particular the tanδ values, related to the usage conditions of the tyre of the vulcanized elastomeric materials used for manufacturing the various parts of the tread band within specific ratios according to the areas of the tread band considered, the "hot" handling and grip performance of the tyre can be improved and maintained at an optimal level over time without compromising the handling and grip performance of the tyre under the above-mentioned "cold" usage conditions.

[0035] In particular, by using a so-called "soft" vulcanized elastomeric material in the inner radial part of the tread band, it has surprisingly been possible to improve and maintain over time the handling and performance of the tyre under "hot" usage conditions, said "soft" vulcanized elastomeric material having a lower elastic modulus and a higher hysteresis than the two vulcanized elastomeric materials used in the outer radial part of the tread band under both cold and hot conditions.

[0036] Improving and maintaining over time the handling and performance of a tire under "hot" usage conditions is surprising because using such a "soft" vulcanized elastomeric material in the radial interior of the tread band would not only seem unsuitable for providing constant performance over time under such usage conditions, but even conversely would tend to cause a rapid decline in tire performance.

[0037] Accordingly, the present invention relates to a motorcycle tire.

[0038] Such a motorcycle tire includes an equatorial plane and a tread band, the tread band including:

[0039] a) a radially outer portion, the radially outer portion including:

[0040] a1) a central sub-portion that extends across the equatorial plane of the tire and is made of a first vulcanized elastomeric material, and

[0041] a2) a pair of lateral sub-portions that are distal relative to the equatorial plane of the tire and are disposed on opposite sides of the central sub-portion, the lateral sub-portions being made of a second vulcanized elastomeric material;

[0042] wherein the first vulcanized elastomeric material of the central sub-portion has a dynamic elastic modulus (E') measured at a frequency of 10 Hz and a temperature of 23°C that is greater than the dynamic elastic modulus (E') of the second vulcanized elastomeric material of the lateral sub-portions measured at a frequency of 10 Hz and a temperature of 23°C;

[0043] wherein the respective dynamic elastic moduli (E') of the first vulcanized elastomeric material of the central sub-portion and the second vulcanized elastomeric material of the lateral sub-portions, measured at a frequency of 10 Hz and a temperature of 23°C, are between 5.2 MPa and 6.5 MPa;

[0044] b) a radially inner portion that extends axially along its entire length below the radially outer portion of the tread band, the radially inner portion being made of a third vulcanized elastomeric material, the third vulcanized elastomeric material having a dynamic elastic modulus (E') measured at a frequency of 10 Hz and a temperature of 23°C that is less than the dynamic elastic modulus (E') of the first vulcanized elastomeric material of the central sub-portion of the radially outer portion of the tread band and the dynamic elastic modulus (E') of the second vulcanized elastomeric material of the lateral sub-portions of the radially outer portion of the tread band, measured at a frequency of 10 Hz and a temperature of 23°C;

[0045] wherein the ratio R1 between the dynamic elastic modulus (E') of the second vulcanized elastomeric material of the lateral sub-portions of the radially outer portion of the tread band, measured at a frequency of 10 Hz and a temperature of 100°C, and the dynamic elastic modulus (E') of the third vulcanized elastomeric material of the radially inner portion of the tread band, measured at a frequency of 10 Hz and a temperature of 70°C, is between 0.8 and 1.2;

[0046] Among them, the ratio R2 between the tanδ measured at 10 Hz and 100 °C of the second vulcanized elastomeric material in the lateral sub-part of the radially outer part of the tread band and the tanδ measured at 10 Hz and 70 °C of the third vulcanized elastomeric material in the radially inner part of the tread band is between 0.8 and 1.2.

[0047] The applicant has experimentally found that by using a tread band of the so-called "crown base" type having the aforementioned characteristics, it is surprisingly possible to improve and maintain over time the handling and performance of motorcycle tires (especially "super sport" and / or "hyper sport" type motorcycle tires) under "hot" usage conditions, while keeping the handling and grip performance under wet and / or cold climatic conditions or on non-optimal road surfaces substantially unchanged.

[0048] Without wishing to be bound by any theory of interpretation, the applicant believes that under "hot" usage conditions, the tire as defined above has substantially uniform tread band dynamic and hysteresis behavior in the shoulder region (i.e., the region where the stress is greatest under such usage conditions).

[0049] The applicant has found that this substantially uniform dynamic and hysteresis behavior is beneficial for limiting the phenomenon of premature tire wear and the decline in tire performance, and can be achieved by controlling the following ratios to values close to 1:

[0050] i) The ratio between the deformation characteristics (related to the value of the dynamic elastic modulus (E') under the corresponding "hot" usage conditions as described above) of the second vulcanized elastomeric material present in the lateral sub-part or shoulder sub-part of the radially outer part of the tread band and the third vulcanized elastomeric material present in the radially inner part of the tread band, and

[0051] ii) The ratio between the hysteresis characteristics (related to the tanδ value under the corresponding "hot" usage conditions as described above) of the second vulcanized elastomeric material and the third vulcanized elastomeric material.

[0052] Surprisingly, as described above, by using the third vulcanized elastomeric material in the radially inner part of the tread band, this advantageous technical effect has been observed. The third vulcanized elastomeric material has a lower elastic modulus and a higher tanδ than the second vulcanized elastomeric material used in the shoulder region of the radially outer part of the tread band under the usage conditions of the tire. These characteristics were considered to cause a rapid decline in tire performance under "hot" usage conditions, but this has proven not to be the case. On the contrary, the third vulcanized elastomeric material actually allows for the improvement and maintenance over time of the handling and performance of the tire under "hot" usage conditions.

[0053] Conversely, and without wishing to be bound by any theory of interpretation, the Applicant believes that, under the "cold" use conditions of the tyre, the third vulcanized elastomeric material in the radially inner part of the tread band deforms (related to the elastic modulus E') and exhibits hysteresis (related to the tanδ parameter), which allows the overlying radially outer part of the "heated" tread band (harder and less hysteretic) to better adhere to the ground under wet and / or cold conditions, thereby obtaining sufficient handling and grip performance under these use conditions.

[0054] Basically, in the tyre according to the invention, the hysteresis characteristics in the shoulder region of the tread band of the tyre and the hysteresis characteristics under "hot" use conditions are effectively combined, and the handling and grip performance under extreme speed and handling conditions on dry and / or hot ground are improved and maintained over time, while effectively differentiating the stiffness and hysteresis characteristics between different parts of the tread band under the "cold" use conditions of the tyre, so as to maintain the handling and grip performance under wet and / or cold climatic conditions or on non-optimal road surfaces.

[0055] In particular, under "hot" use conditions, from the perspective of deformability and hysteresis, the behavior of the assembly formed by the lateral sub-part or shoulder sub-part of the radially outer part of the tread band of the tyre according to the invention and the part of the radially inner part of the tread band located below these sub-parts is like that the assembly is substantially composed of a single vulcanized elastomeric material having optimal characteristics under these use conditions.

[0056] Advantageously, the tyre according to the invention thus not only achieves improved handling and grip performance under extreme speed and handling conditions on dry and / or hot surfaces, but also is able to maintain this performance for a longer time.

[0057] In addition, under "hot" use conditions, from the perspective of deformability and hysteresis, the assembly formed by the central sub-part of the radially outer part of the tread band and the part of the radially inner part of the tread band located below this sub-part of the tyre according to the invention also performs optimally under straight-line driving conditions, where any unevenness of the road surface needs to be suppressed as much as possible.

[0058] In this specification and the claims hereinafter, unless otherwise indicated, all numerical entities representing quantities, parameters, percentages, etc. should be understood to be preceded by the term "about" in all cases. In addition, except for those specifically indicated hereinafter, all ranges of numerical entities include all possible combinations of the maximum and minimum numerical values and all possible intermediate ranges.

[0059] Unless otherwise specified, all ranges of numerical entities also include the maximum and minimum numerical values.

[0060] For the purposes of the present invention, the following definitions apply.

[0061] The term "phr" (an abbreviation for parts per hundred rubber) represents the number of parts by weight of a given component of an elastomeric rubber composite per 100 parts by weight of an elastomeric polymer, the elastomeric polymer being considered free of any plasticizing extender oil.

[0062] The terms "elastomeric material", "rubber", "elastomeric polymer" or "elastomer" are used to denote a material comprising a vulcanizable natural or synthetic polymer and reinforcing fillers, wherein such material, after vulcanization at room temperature, can withstand deformation caused by a force and is capable of rapidly and strongly returning to substantially its original shape and dimensions (as defined in the ASTM standard D1566 - 11, Standard Terminology Relating to Rubber).

[0063] The term "diene polymer" is used to denote a polymer or copolymer obtained by the polymerization of one or more different monomers, at least one of which is a conjugated diene (conjugated diolefin).

[0064] The term "rubber composite" or "elastomeric rubber composite" is used to denote a mixture obtained by mixing and possibly heating at least one elastomeric polymer with at least one additive typically used in the preparation of rubber composites for tires.

[0065] The term "vulcanizable rubber composite" or "vulcanizable elastomeric rubber composite" is used to denote an elastomeric mixture ready for vulcanization, obtainable by incorporating all additives including vulcanization additives into the elastomeric rubber composite.

[0066] The term "vulcanized elastomeric material" is used to denote a material obtained by vulcanizing a vulcanizable elastomeric rubber composite.

[0067] The term "vulcanization" is used to denote the cross - linking reaction in natural or synthetic rubber caused by a cross - linking agent, typically a sulfur - based agent.

[0068] The term "vulcanizing agent" is used to denote a compound capable of transforming natural or synthetic rubber into an elastic and strong material by forming a three - dimensional network of intermolecular and intramolecular bonds. Typical vulcanizing agents are sulfur - based compounds such as elemental sulfur, polymeric sulfur, sulfur donor agents such as bis[(trialkoxysilyl)propyl] polysulfides, thiurams, dithiodimorpholine and caprolactam disulfide.

[0069] The term "vulcanization accelerator" is used to denote a compound capable of reducing the duration of the vulcanization process and / or reducing the operating temperature, such as TBBS, sulfenamides, thiazoles, dithiophosphates, dithiocarbamates, guanidines and sulfur donors such as thiurams.

[0070] The term "vulcanization activator" is used to denote a compound that can further promote vulcanization, thereby allowing vulcanization to occur in a shorter time and possibly at a lower temperature. An example of an activator is the stearic acid - zinc oxide system.

[0071] The term "vulcanization retarder" is used to denote a compound that can delay the start of the vulcanization reaction and / or inhibit unwanted side reactions, such as N-(cyclohexylthio)phthalimide (CTP).

[0072] The term "reinforcing filler" is used to denote a reinforcing material typically used to improve the mechanical properties of tire rubber, preferably selected from carbon black and "white fillers".

[0073] The term "white filler" is used to denote traditional reinforcing materials used in the art, selected from traditional silica and silicates, such as amorphous silica sand preferably precipitated with strong acid, diatomaceous earth, calcium carbonate, titanium dioxide, talc, alumina, aluminosilicates, kaolin, silicate fibers, layered silicates (such as sepiolite, palygorskite (also known as attapulgite), montmorillonite, halloysite and the like, which are optionally modified and / or derivatized by acid treatment) and mixtures thereof. Generally, white fillers have surface hydroxyl groups.

[0074] The term "motorcycle tire" is used to denote a tire having a high curvature ratio (typically greater than 0.20) and capable of achieving a high camber angle during turning.

[0075] The term "curvature ratio" is used to denote the ratio of the distance (also represented by the "arrow") between the radially highest point of the tread band and the maximum width (also known as the "maximum chord") of the radial cross-section of the tire in the cross-section of the tire to the said maximum width.

[0076] The "axial extension" of the tread band or a part thereof is used to denote the extension of the radially outermost contour of the tread band or a part thereof in the cross-section intercepted in a plane containing the rotational axis of the tire.

[0077] The "axial half-extension" of the tread pattern, tread band or a part thereof is used to denote the extension from the equatorial plane towards the axially outermost end of the tire of the radially outermost contour of the tread band or a part thereof in the cross-section intercepted in a plane containing the rotational axis of the tire.

[0078] The "equatorial plane" of a tire refers to the plane perpendicular to the rotational axis of the tire and dividing the tire into two symmetrically equal parts.

[0079] The term "width" is used to denote the dimension measured in a direction perpendicular to the equatorial plane.

[0080] The term "tread pattern" is used to denote the presentation of all points of the tread band (including the grooves) in a plane perpendicular to the equatorial plane of the tire and tangent to the maximum diameter of the tire. The tread pattern is defined by a plurality of land portions separated by grooves and may include sipes.

[0081] The terms "radial" and "axial" and the expressions "radially in / out" and "axially in / out" are used by reference to a direction substantially parallel to the equatorial plane of the tire and a direction substantially perpendicular to the equatorial plane of the tire, respectively, i.e., by reference to a direction substantially perpendicular to the axis of rotation of the tire and a direction substantially parallel to the axis of rotation of the tire, respectively.

[0082] The terms "circumferential" and "circumferentially" are used by reference to the circumferential extension direction of the tire, i.e., by reference to the rolling direction of the tire, which corresponds to a direction lying in a plane coinciding with or substantially parallel to the equatorial plane of the tire.

[0083] The "circumferential extension" of a tire, tread band or part thereof is used to denote the planar extension of the radially outermost surface of the tire, tread band or part thereof in a plane tangent to the tire.

[0084] The expressions "axially innermost" and "axially outermost" denote positions closer to and further from the equatorial plane, respectively, relative to a reference element.

[0085] The term "radial carcass structure" is used to denote a carcass structure including a plurality of reinforcing cords, each reinforcing cord being oriented in a substantially axial direction in the crown portion of the tire. Such reinforcing cords may be incorporated into a single carcass ply or may be incorporated into a plurality of carcass plies (preferably two) radially superposed on one another.

[0086] The term "substantially axial direction" is used to denote a direction inclined at an angle between 60° and 90° relative to the equatorial plane of the tire.

[0087] The term "substantially circumferential direction" is used to denote a direction oriented at an angle between 0° and 20° relative to the equatorial plane of the tire.

[0088] The "static mechanical properties" of a tread rubber compound are used to denote the stress-strain properties of the vulcanized rubber and thermoplastic rubber under traction measured on a sample of the vulcanized rubber compound (170 °C, for 10 minutes) at a predetermined temperature in accordance with UNI standard 6065:2001.

[0089] The "dynamic mechanical properties" of a tread rubber compound are used to denote the mechanical properties measured in tension-compression mode using the Instron dynamic device model 1341 described herein.

[0090] A crosslinked material test piece with a cylindrical shape (length = 25 mm; diameter = 18 mm) is tested (at 170 °C for 15 minutes), preloaded under compression to a maximum longitudinal deformation of 25% of the initial length, and maintained at a predetermined temperature (e.g., 23 °C, 70 °C, and 100 °C) throughout the test. After waiting for 2 minutes, the test piece is mechanically pre-treated 125 times at 10 Hz with a deformation amplitude of 7.5% of the length under preload, and then the test piece is subjected to dynamic sinusoidal stress with an amplitude of ±3.5% of the length under preload and a predetermined frequency of, for example, 10 Hz. The dynamic mechanical properties are expressed as values of the elastic dynamic modulus (E') and tanδ (loss factor). The tanδ value is calculated as the ratio between the viscous dynamic modulus (E") and the elastic dynamic modulus (E').

[0091] One or more of the aspects of the present invention may have one or more of the preferred features given below, and these preferred features may be combined according to application requirements.

[0092] Preferably, the respective dynamic elastic moduli (E') measured at a frequency of 10 Hz and 23 °C for the first vulcanized elastomeric material of the central sub - portion and the second vulcanized elastomeric material of the lateral sub - portion of the radially outer portion of the tread band are between 5.8 MPa and 6.4 MPa.

[0093] In this way, it is possible to advantageously endow the tread band with sufficient stiffness characteristics under the "cold" usage conditions of the tire.

[0094] Preferably, the ratio R1 between the dynamic elastic modulus (E') measured at a frequency of 10 Hz and 100 °C for the second vulcanized elastomeric material of the lateral sub - portion of the radially outer portion of the tread band and the dynamic elastic modulus (E') measured at a frequency of 10 Hz and 70 °C for the third vulcanized elastomeric material of the radially inner portion of the tread band is between 0.9 and 1.1.

[0095] Advantageously, this preferred feature helps to optimize the handling and performance of the tire under extreme speed and handling conditions on dry and / or hot surfaces during cornering and keeps them substantially constant over time, because from the perspective of its "thermal" deformation ability, the shoulder region of the tread band of the tire is formed of a vulcanized elastomeric material, and from the perspective of its behavior on the road, this vulcanized elastomeric material is substantially "homogeneous".

[0096] Preferably, the ratio R2 between the tanδ measured at a frequency of 10 Hz and 100 °C for the second vulcanized elastomeric material of the lateral sub - portion of the radially outer portion of the tread band and the tanδ measured at a frequency of 10 Hz and 70 °C for the third vulcanized elastomeric material of the radially inner portion of the tread band is between 0.9 and 1.1.

[0097] Also in this case, this preferred feature is conducive to optimizing the handling and performance of the tire under extreme speed and handling conditions on dry and / or hot surfaces during cornering and keeping them substantially constant over time, because from the perspective of its "thermal" deformation ability, the shoulder region of the tread of the tire is formed of a vulcanized elastomeric material, and from the perspective of its behavior on the road, this vulcanized elastomeric material is substantially "homogeneous".

[0098] Preferably, the dynamic elastic modulus (E') of the first vulcanized elastomeric material of the central sub - portion of the radially outer portion of the tread is between 5.1 MPa and 5.5 MPa, more preferably between 5.2 MPa and 5.4 MPa, measured at a frequency of 10 Hz and a temperature of 70 °C.

[0099] Preferably, the tanδ of the first vulcanized elastomeric material of the central sub - portion of the radially outer portion of the tread is between 0.26 and 0.30, more preferably between 0.27 and 0.29, measured at a frequency of 10 Hz and a temperature of 70 °C.

[0100] Preferably, the dynamic elastic modulus (E') of the second vulcanized elastomeric material of the lateral sub - portion of the radially outer portion of the tread is between 2.5 MPa and 2.9 MPa, more preferably between 2.6 MPa and 2.8 MPa, measured at a frequency of 10 Hz and a temperature of 100 °C.

[0101] Advantageously, this preferred feature helps to achieve the best ground contact performance and the best grip of the tire on the ground in order to improve the handling and performance of the tire under "hot" usage conditions.

[0102] Preferably, the tanδ of the second vulcanized elastomeric material of the lateral sub - portion of the radially outer portion of the tread is between 0.24 and 0.28, more preferably between 0.25 and 0.27, measured at a frequency of 10 Hz and a temperature of 100 °C.

[0103] Also in this case, this preferred feature advantageously helps to achieve the best ground contact performance and the best grip of the tire on the ground in order to improve the handling and performance of the tire under "hot" usage conditions.

[0104] Preferably, the dynamic elastic modulus (E') of the third vulcanized elastomeric material of the radially inner portion of the tread is between 2.5 MPa and 2.9 MPa, more preferably between 2.6 MPa and 2.8 MPa, measured at a frequency of 10 Hz and a temperature of 70 °C.

[0105] Advantageously, this preferred feature allows the third vulcanized elastomeric material of the radially inner portion of the tread to effectively contribute to achieving the best handling and performance of the tire under "hot" usage conditions.

[0106] In fact, under such "hot" use conditions, the third vulcanized elastomeric material of the radially inner part of the tread band simultaneously has deformable characteristics related to the value of the dynamic elastic modulus (E'), and the deformable characteristics are appropriately differentiated in each region of the tread band and can achieve the high stability characteristics of the tread band as a whole from a dynamic perspective under "hot" use conditions.

[0107] In fact, the deformation characteristics of the third vulcanized elastomeric material are basically the same as those of the second vulcanized elastomeric material of the shoulder sub-part of the radially outer part of the tread band, but are much lower than those of the first vulcanized elastomeric material of the central sub-part of the radially outer part of the tread band, thereby allowing the "imitation" of the hysteresis behavior of the shoulder part and the "heating" of the central sub-part of the tread band formed by the less deformed rubber composite.

[0108] Preferably, the tanδ of the third vulcanized elastomeric material of the radially inner part of the tread band measured at a frequency of 10 Hz and 70 °C is between 0.25 and 0.29, and more preferably between 0.26 and 0.28.

[0109] Advantageously, this preferred feature also allows the third vulcanized elastomeric material of the radially inner part of the tread band to effectively contribute to achieving the optimal handling and performance of the tire under "hot" use conditions, in which case the hysteresis characteristics related to the tanδ value of the third vulcanized elastomeric material are basically the same as those of the first and second vulcanized elastomeric materials of the radially outer part of the tread band.

[0110] Preferably, the dynamic elastic modulus (E') of the first vulcanized elastomeric material of the central sub-part of the radially outer part of the tread band measured at a frequency of 10 Hz and 23 °C is between 6.0 MPa and 6.5 MPa, and more preferably between 6.2 MPa and 6.4 MPa.

[0111] Preferably, the tanδ of the first vulcanized elastomeric material of the central sub-part of the radially outer part of the tread band measured at a frequency of 10 Hz and 23 °C is between 0.40 and 0.44, and more preferably between 0.41 and 0.43.

[0112] Preferably, the dynamic elastic modulus (E') of the second vulcanized elastomeric material of the lateral sub-part of the radially outer part of the tread band measured at a frequency of 10 Hz and 23 °C is between 5.5 MPa and 6.0 MPa, and more preferably between 5.7 MPa and 5.9 MPa.

[0113] Preferably, the second vulcanized elastomeric material of the lateral sub - part of the radially outer part of the tread band has a tanδ measured at a frequency of 10 Hz and a temperature of 23 °C between 0.66 and 0.70, more preferably between 0.67 and 0.69.

[0114] In this way, it is possible to advantageously achieve the best grip of the tire on the ground in order to improve the handling and performance of the tire under "cold" usage conditions.

[0115] Preferably, the dynamic elastic modulus (E’) of the third vulcanized elastomeric material of the radially inner part of the tread band, measured at a frequency of 10 Hz and a temperature of 23 °C, is between 4.0 MPa and 5.0 MPa, more preferably between 4.2 MPa and 4.5 MPa.

[0116] Advantageously, this preferred feature allows the third vulcanized elastomeric material of the radially inner part of the tread band to effectively contribute to achieving the best ground contact area and the best grip of the tire on the ground in order to improve the handling and performance of the tire under "cold" usage conditions.

[0117] Preferably, the tanδ of the third vulcanized elastomeric material of the radially inner part of the tread band, measured at a frequency of 10 Hz and a temperature of 23 °C, is between 0.49 and 0.53, more preferably between 0.50 and 0.52.

[0118] Advantageously, this preferred feature also allows the third vulcanized elastomeric material of the radially inner part of the tread band to effectively contribute to achieving the best ground contact area and the best grip of the tire on the ground in order to improve the handling and performance of the tire under "cold" usage conditions.

[0119] Preferably, the ratio R3 between the tanδ of the first vulcanized elastomeric material of the central sub - part of the radially outer part of the tread band, measured at a frequency of 10 Hz and a temperature of 70 °C, and the tanδ of the third vulcanized elastomeric material of the radially inner part of the tread band, measured at a frequency of 10 Hz and a temperature of 70 °C, is between 0.5 and 1.2, more preferably between 0.7 and 1.0.

[0120] In this way, it is possible to advantageously optimize the handling and performance of the tire under "hot" usage conditions and during straight - line travel and keep them substantially constant over time, since the central region of the tire's tread band is formed of vulcanized elastomeric materials that are substantially "homogeneous" from the perspective of hysteresis in both its radially outer part and its radially inner part.

[0121] Preferably, the ratio R4 between the dynamic elastic modulus (E’) measured at 10 Hz and 70 °C of the first vulcanized elastomeric material of the central sub - part of the radially outer portion of the tread band and the dynamic elastic modulus (E’) measured at 10 Hz and 70 °C of the third vulcanized elastomeric material of the radially inner portion of the tread band is between 1.3 and 2.0, more preferably between 1.5 and 1.8.

[0122] In this way, it is possible to advantageously optimize the handling and performance of the tire during straight - line travel on dry and / or hot surfaces under fast - driving conditions and keep them substantially constant over time, because from the perspective of its "thermal" deformation ability, the central region of the tread band of the tire is formed by such a vulcanized elastomeric material that, due to the modulus characteristics of the central sub - part of the radially outer portion of the tread band, the vulcanized elastomeric material adapts well to the roughness of the ground, and at the same time, due to the modulus characteristics of the radially inner portion of the tread band, the vulcanized elastomeric material achieves high grip.

[0123] Preferably, the ratio R5 between the dynamic elastic modulus (E’) measured at 10 Hz and 23 °C of the second vulcanized elastomeric material of the lateral sub - part of the radially outer portion of the tread band and the dynamic elastic modulus (E’) measured at 10 Hz and 23 °C of the third vulcanized elastomeric material of the radially inner portion of the tread band is between 1.1 and 1.6, more preferably between 1.2 and 1.5.

[0124] In this way, it is possible to advantageously achieve an excellent level of handling and performance of the tire under "cold" usage conditions, such as during the warm - up phase of the tire or under high - demand camber conditions on a wet road surface and / or in cold climate conditions or on non - optimal road surfaces.

[0125] Without being bound by any theory of interpretation, the applicant believes that in this case, the third vulcanized elastomeric material of the radially inner portion of the tread band allows the lateral sub - part or the shoulder sub - part of the radially outer portion of the tread band to deform sufficiently, thereby increasing their ground contact area.

[0126] Preferably, the ratio R6 between the tanδ measured at 10 Hz and 23 °C of the second vulcanized elastomeric material of the lateral sub - part of the radially outer portion of the tread band and the tanδ measured at 10 Hz and 23 °C of the third vulcanized elastomeric material of the radially inner portion of the tread band is between 1.1 and 1.6, more preferably between 1.2 and 1.5.

[0127] Preferably, the ratio R7 between the dynamic elastic modulus (E’) measured at 10 Hz and 23 °C of the first cured elastomeric material of the central sub - part of the radially outer portion of the tread band and the dynamic elastic modulus (E’) measured at 10 Hz and 23 °C of the third cured elastomeric material of the radially inner portion of the tread band is between 1.2 and 1.8, more preferably between 1.3 and 1.7.

[0128] Preferably, the ratio R8 between the tanδ measured at 10 Hz and 23 °C of the first cured elastomeric material of the central sub - part of the radially outer portion of the tread band and the tanδ measured at 10 Hz and 23 °C of the third cured elastomeric material of the radially inner portion of the tread band is between 0.6 and 1.1, preferably between 0.7 and 1.0.

[0129] In this way, it is possible to advantageously achieve an excellent level of handling and performance of the tire under "cold" usage conditions, such as during the warm - up phase of the tire or when traveling in a straight line on a wet surface and / or in cold climatic conditions or on non - optimal road surfaces.

[0130] Without being bound by any theory of interpretation, the applicant believes that, in this case, the hysteresis of the third cured elastomeric material of the radially inner portion of the tread band is substantially equal to or suitably greater than the hysteresis of the first cured elastomeric material of the central sub - part of the radially outer portion of the tread band, thus allowing for sufficient thermal operation of the aforementioned central sub - part and increasing its ground contact area.

[0131] Preferably, the ratio R9 between the dynamic elastic modulus (E’) measured at 10 Hz and 23 °C of the third cured elastomeric material of the radially inner portion of the tread band and the dynamic elastic modulus (E’) measured at 10 Hz and 70 °C of the same cured elastomeric material is between 1.2 and 2.0, more preferably between 1.4 and 1.9.

[0132] Advantageously, this preferred feature allows the third cured elastomeric material of the radially inner portion of the tread band to have an optimal "flexibility" of its deformation characteristics under "cold" and "hot" usage conditions, and this flexibility effectively contributes to achieving the following advantageous technical effects.

[0133] First, it contributes to the technical effect of improving and maintaining over time the handling and performance of the tire under "hot" usage conditions, due to the cooperation between the third cured elastomeric material of the radially inner portion of the tread band and the second cured elastomeric material of the lateral sub - part or the shoulder sub - part of the radially outer portion of the tread band, and the "hot" dynamic elastic moduli, i.e., the degrees of deformation, of these elastomeric materials are very close to each other (see the value of the aforementioned ratio R1).

[0134] Secondly, there is a technical effect that helps to maintain an excellent level of handling and performance of the tire under "cold" usage conditions (e.g., during the tire warm-up phase or when used on wet ground and / or in cold climatic conditions or on non-optimal road surfaces). This is due to the cooperation between the third vulcanized elastomeric material in the radially inner part of the tread band and the first vulcanized elastomeric material in the central sub-part of the radially outer part of the tread band, and the "cold" dynamic elastic moduli of these elastomeric materials, i.e., the degrees of deformation, are significantly different from each other (see the value of the aforementioned ratio R7).

[0135] In fact, under the "cold" usage conditions of the tire, compared with the first vulcanized elastomeric material in the central sub-part of the radially outer part of the tread band, the deformability and hysteresis of the third vulcanized elastomeric material in the radially inner part of the tread band are much higher, which is beneficial to heating the tread band during the warm-up phase and helps to increase the grip of the tire on wet surfaces and / or in cold climatic conditions or on non-optimal road surfaces at "cold" operating temperatures.

[0136] Preferably, the ratio R10 between the tanδ of the third vulcanized elastomeric material in the radially inner part of the tread band measured at a frequency of 10 Hz and 23 °C and the tanδ of the same vulcanized elastomeric material measured at a frequency of 10 Hz and 70 °C is between 1.5 and 2.4, and more preferably between 1.7 and 2.1.

[0137] Advantageously, this preferred feature also allows the third vulcanized elastomeric material in the radially inner part of the tread band to have the best "flexibility" of its hysteresis characteristics under "cold" and "hot" usage conditions, and this flexibility effectively helps to achieve the above-mentioned advantageous technical effects.

[0138] Preferably, the tire is a tire for use on the rear wheel of a motorcycle, and its lateral curvature ratio is equal to or greater than about 0.30 and preferably between 0.30 and 0.35. BRIEF DESCRIPTION OF THE DRAWINGS

[0139] With reference to the accompanying drawings, other features and advantages of the present invention will become more apparent from the following description of some preferred embodiments given for illustrative and non-limiting purposes.

[0140] These figures are schematic and not drawn to scale.

[0141] In the drawings:

[0142] - Figure 1 shows a perspective view of a tire according to a preferred embodiment of the present invention, which is intended to be mounted on the rear wheel of a motorcycle; and

[0143] - Figure 2 is Figure 1 an enlarged schematic cross-section of the tire. Detailed implementation mode

[0144] In the figure, reference numeral 1 generally represents a tire for a motorcycle wheel according to a preferred embodiment of the present invention. This is a tire preferably intended for use on the rear wheel of a large-displacement (e.g., 600 cc) supersport motorcycle.

[0145] An equatorial plane X-X and a rotation axis (not shown) are defined in the tire 1. A circumferential direction (represented by an arrow F oriented in the rotation direction of the tire 1 in Figure 1 and an axial direction (represented by an axis r perpendicular to the equatorial plane X-X in Figure 2 ) are also defined.

[0146] The tire 1 includes a carcass structure 2 formed by at least one carcass ply 3, and the carcass ply includes a plurality of reinforcing elements (cords).

[0147] The carcass structure 2 is typically coated on its inner wall with a sealing layer or a so-called "liner", which is mainly composed of an airtight elastomeric material layer suitable for ensuring an airtight seal after the tire is inflated.

[0148] The reinforcing elements contained in the carcass ply 3 preferably include fabric cords made of a fiber material.

[0149] The fiber material for manufacturing the cords can be made of fibers of natural or synthetic origin, and the fibers are selected from rayon, lyocell, polyester (e.g., PEN, PET, PVA), aromatic polyamides (e.g., such as aromatic polyamides), and these can be used alone or in combination. More particularly, the fiber material for manufacturing the cords is preferably selected from polyester, rayon, lyocell, aromatic polyamides, or a hybrid material formed by two or more of the above materials.

[0150] The reinforcing elements contained in at least one carcass ply 3 are preferably arranged in the radial direction, that is, at an angle between 70° and 110°, more preferably between 80° and 100°, with respect to the circumferential direction.

[0151] At least one carcass ply 3 is formed according to a generally annular configuration and is joined to at least one annular reinforcing structure through its opposite circumferential edges 3a.

[0152] In particular, the opposite lateral edges 3a of at least one carcass ply 3 can be turned up around the annular reinforcing structure, and each annular reinforcing structure includes one or more metal annular bead cores 4 and a tapered elastomeric filler 5, and the tapered elastomeric filler occupies the space defined between the carcass ply 3 and the corresponding turned-up lateral edge 3a of the carcass ply 3.

[0153] The area of the tire that includes the bead core 4 and the filler 5 forms the so-called bead 9, which is intended to anchor the tire 1 to a corresponding mounting rim (not shown).

[0154] In an embodiment (not shown), at least one carcass ply 3 is made by gathering together a plurality of strips of elastomeric material reinforced by the aforementioned cords, and its opposite lateral edges are joined to a specific annular reinforcement structure provided with two annular inserts without being turned up. The filler made of elastomeric material can be arranged at an axially outer position relative to the first annular insert. On the other hand, the second annular insert can be arranged at an axially outer position relative to the end of the carcass ply. Finally, at an axially outer position relative to the second annular insert (and not necessarily in contact therewith), another filler can be provided, which concludes the construction of the annular reinforcement structure.

[0155] The belt structure 6 is applied circumferentially to the carcass structure 2 at a radially outer position, and the belt structure includes at least one belt ply 6a, which is typically formed by cords coated with rubber.

[0156] Preferably, the belt ply 6a is made of cords that are substantially parallel to each other and arranged side by side to form a plurality of coils. Such coils are substantially oriented according to the circumferential direction (typically having an angle between 0° and 5°), with reference to their laying direction relative to the circumferential direction of the tire, which direction is usually referred to as "zero degree".

[0157] Preferably, the "zero degree" ply 6a can include axially adjacent turns of a single cord, or a rubber-coated fabric strip containing axially adjacent cords.

[0158] The cords of the ply 6a are fabric cords or metal cords. Preferably, the cords are metal cords made of steel wires having a high carbon content, in other words, made of steel wires with a carbon content of at least 0.6% - 0.7%.

[0159] Preferably, such metal cords have a high elongation rate (HE).

[0160] To improve the adhesion between the belt structure 6 and the carcass structure 2, an adhesion layer 7 made of elastomeric material can be provided between the two structures.

[0161] In an embodiment (not shown), the belt structure 6 can be composed of at least two radially superposed layers. Each layer is arranged such that the cords of the first belt ply are inclinedly oriented relative to the circumferential direction of the tire, while the cords of the second layer also have an inclined orientation but cross substantially symmetrically with respect to the cords of the first layer.

[0162] The tread band 8 is circumferentially stacked on the belt structure 6, and after a molding operation carried out simultaneously with the vulcanization of the tire, longitudinal and / or transverse grooves are typically formed in the tread band, and these grooves are arranged to delimit a desired tread pattern.

[0163] Figure 1 A tread pattern is shown as a non-limiting example, and the tread pattern includes a plurality of grooves arranged in different ways on opposite sides of the equatorial plane X-X of the tire 1.

[0164] Preferably, the tread pattern includes a series of first circumferential grooves 13 that are substantially L-shaped, a series of second circumferential grooves 14 located at an axially outer position relative to the first circumferential grooves 13, and a series of third circumferential groove groups 15a, 15b, 15c, and 15d, and these groove groups have different inclinations relative to the equatorial plane X-X of the tire 1 and are circumferentially inserted between the first circumferential grooves 13.

[0165] For simplicity, Figure 2 these grooves are not shown in the figure.

[0166] The tire 1 may include a pair of sidewalls 10, and the pair of sidewalls are laterally applied to the carcass structure 2 on its opposite sides.

[0167] The tire 1 has a section height H measured on the equatorial plane X-X between the top of the tread band 8 and the assembly diameter (identified by the reference line r) passing through the bead of the tire 1.

[0168] The tire 1 also has a maximum width C of its transverse section, which is defined by the distance between the axially opposite ends E of the contour of the tread band 8, and the tire also has a curvature ratio, which is defined as the ratio of the distance f (measured on the equatorial plane of the tire 1) between the top of the tread band 8 and the line passing through the ends E of the tread band 8 itself to the aforementioned maximum width C. The axially opposite ends E of the tread band 8 may be formed at the edges.

[0169] In particular, the tire 1 has a transverse section characterized by a high curvature ratio, and preferably, the curvature ratio f / C is at least about 0.30.

[0170] In a preferred embodiment, the motorcycle tire 1 of the present invention is intended to be mounted on the rear wheel with a chord length dimension generally between 160 mm and 210 mm.

[0171] Preferably, the distance f between the radially outermost point of the tread band 8 and the line passing through the axially opposite ends E of the tread band 8 itself of the tire 1 is generally between 50 mm and 70 mm.

[0172] Preferably, for a tire 1 intended to be mounted on the rear wheel of a motorcycle, the transverse curvature ratio f / C is approximately equal to or greater than about 0.30, and even more preferably between 0.30 and 0.35.

[0173] Preferably, the total height / chord length ratio H / C is approximately between 0.5 and 0.65.

[0174] In a preferred embodiment, when the tire 1 has sidewalls 10 of significant height, the tire allows for better performance. For example, when the tire 1 is intended to be mounted on the rear wheel of a motorcycle, the value of the sidewall height ratio (H - f) / H is equal to or greater than 0.35, and more preferably equal to or greater than 0.4.

[0175] Preferably, the ratio of the shoulder radius of the tire 1 to the maximum cross-sectional width is equal to or greater than 0.60.

[0176] According to the present invention, the tread band 8 is of the so-called "crown base" type and is made of at least three different elastomeric materials.

[0177] In the preferred embodiment shown in the drawings, the tread band 8 includes a radially outer portion 11, which includes:

[0178] a1) a central sub-portion 11a arranged across the equatorial plane X-X of the tire 1 and made of a first vulcanized elastomeric material, and

[0179] a2) a pair of lateral sub-portions 11b, 11c, which are located distally relative to the equatorial plane X-X of the tire 1 and are arranged on opposite sides of the central sub-portion 11a.

[0180] As described above, the lateral sub-portions 11b, 11c of the tread band 8 are made of a second vulcanized elastomeric material.

[0181] In the preferred embodiment shown in the drawings, the tread band 8 includes a radially inner portion 12, which extends axially along its entire length below the radially outer portion 11 of the tread band 8.

[0182] As described above, the radially inner portion 12 of the tread band 8 is made of a third vulcanized elastomeric material.

[0183] Preferably, the annular central sub-portion 11a of the tread band 8 has an axial extent L1, which transversely extends 25% - 40% of the total axial extent L of the tread band 8, and more preferably transversely extends 30% - 35% thereof.

[0184] Preferably, the lateral sub-portions 11b, 11c of the tread band 8 have respective axial extents L2, L3, which transversely extend 25% - 40% of the total axial extent L of the tread band 8, and more preferably transversely extend 30% - 35% thereof.

[0185] The central sub - part 11a of the radially outer part 11 of the tread band 8 is advantageously formed in one piece, for example, by laying at least one continuous elongate element of the aforementioned first vulcanized elastomeric material in a continuous circumferential helix.

[0186] Conversely, the lateral sub - parts 11b, 11c of the radially outer part 11 of the tread band 8 are advantageously formed in one piece, for example, by laying at least one continuous elongate element made of the aforementioned second vulcanized elastomeric material in a continuous circumferential coil.

[0187] In this way and as described above, a pair of interfaces 16 between the first and second vulcanized elastomeric materials are defined in the radially outer part 11 of the tread band 8 and are located on opposite sides of the equatorial plane X - X of the tire 1 and the central annular part 11a.

[0188] Thus, in this preferred configuration of the tread band 8, the interfaces 16 separate the central sub - part 11a of the radially outer part 11 of the tread band 8 from the lateral sub - parts 11b, 11c in the axial direction.

[0189] Preferably, the lateral sub - parts 11b, 11c of the radially outer part 11 of the tread band 8 and thus the interfaces 16 are arranged at a distance from the equatorial plane X - X of the tire 1, as described above, the distance being between 25% - 40% of the semi - axial extension L / 2 of the tread band, more preferably between 30% - 35% thereof.

[0190] In Figure 2 In the preferred embodiment shown, the interfaces 16 can converge from the inner side to the outer side of the tread band 8 towards the equatorial plane X - X of the tire 1, the interfaces being oriented in a direction inclined at an angle between 30° and 50°, preferably between 35° and 40°, with respect to the equatorial plane X - X.

[0191] In this preferred configuration of the tread band 8, the radially inner part 12 of the tread band 8 substantially extends over the entire axial extension of the belt structure 6.

[0192] Thus, in this preferred configuration of the tread band 8, the radially inner part 12 of the tread band 8 is interposed in the radial direction between the belt structure 6, the central sub - part 11a and the lateral sub - parts 11b, 11c of the radially outer part 11 of the tread band 8.

[0193] The rubber compounds for the different parts of the tread band 8 and for other semi - finished products for forming the tire 1 include at least one elastomeric diene polymer (a1).

[0194] Advantageously, such rubber compounds include at least one alpha - olefin and have a specific formulation, as will be described in more detail below.

[0195] According to one embodiment, the at least one elastomeric diene polymer (a1) may be selected, for example, from elastomeric diene polymers commonly used in elastomeric compositions capable of being crosslinked (vulcanized) with sulfur, said elastomeric compositions being particularly suitable for the manufacture of tires, i.e., from elastomeric polymers or copolymers having unsaturated chains, the glass transition temperature (Tg) of said elastomeric polymers or copolymers having unsaturated chains generally being below 20°C, preferably in the range of 0°C to 110°C. These polymers and copolymers may be of natural origin or may be obtained by solution polymerization, emulsion polymerization or gas-phase polymerization of one or more conjugated dienes, optionally mixed with at least one comonomer selected from mono-vinyl aromatic hydrocarbons and / or polar comonomers.

[0196] Preferably, for the tread rubber compound, polybutadiene (BR) and / or styrene-butadiene polymer (SBR) may be used alone or in admixture, such as SSBR (solution-polymerized styrene-butadiene elastomer) or E-SBR (emulsion-polymerized styrene-butadiene elastomer).

[0197] Preferably, the styrene-butadiene polymer (SBR) may be present in the rubber compound of the present invention in various amounts in the range of about 50 phr to 100 phr, more preferably in the range of 70 phr to 100 phr.

[0198] Advantageously, polybutadiene (BR) may be absent from the rubber compound of the present invention or may be included in the rubber compound of the present invention, particularly in the tread rubber compound, in an amount of about 0 phr to 40 phr, more preferably about 10 phr to 30 phr.

[0199] Preferably, the styrene-butadiene polymer may be obtained from solution or emulsion and generally comprises styrene in an amount of about 10% to 40% by weight, preferably about 15% to 30% by weight.

[0200] Preferably, the styrene-butadiene polymer may have a low molecular weight, with an average molecular weight Mn below 200,000 g / mol, preferably between 150,000 and 200,000 g / mol.

[0201] The elastomeric material of the different parts of the tread band 8 comprises at least one reinforcing filler present in an amount generally between 1 phr and 130 phr.

[0202] Such a reinforcing filler is preferably selected from carbon black and so-called white fillers: silica, alumina, silicates, hydrotalcite, calcium carbonate, kaolin, titanium dioxide and mixtures thereof.

[0203] The reinforcing filler used in the elastomeric material of different parts of the tread band 8 may include only carbon black, or may include both carbon black and one or more white fillers (e.g., silica).

[0204] In a preferred embodiment, the first vulcanized elastomeric material of the central sub - part 11a of the radially outer part 11 of the tread band 8 includes the "white" reinforcing filler as defined above, in an amount greater than 75% by weight of the total weight of the reinforcing filler, preferably equal to or greater than 80%, more preferably equal to or greater than 85%, more preferably equal to or greater than 90%, more preferably equal to or greater than 95%.

[0205] More preferably, such "white" reinforcing filler is selected from silica, alumina, silicate, hydrotalcite, calcium carbonate, kaolin, titanium dioxide and mixtures thereof.

[0206] Even more preferably, the "white" reinforcing filler may be fumed silica or precipitated silica, the BET surface area of which (measured according to ISO standard 5794 / 1) is between 50 m 2 / g and 500 m 2 / g, preferably between 70 m 2 / g and 200 m 2 / g.

[0207] In this way, it is possible to advantageously achieve a rapid temperature rise of the tread band 11 of the tire 1 and excellent grip under different road surface conditions.

[0208] In a preferred embodiment, the second elastomeric material of the lateral sub - parts 11b, 11c of the radially outer part 11 of the tread band 8 includes carbon black, the amount of which is greater than 75% by weight of the total weight of the reinforcing filler, preferably equal to or greater than 80%, more preferably equal to or greater than 85%, more preferably equal to or greater than 90%, more preferably equal to or greater than 95%.

[0209] Preferably, the carbon black is selected from carbon blacks having a surface area of not less than 20 m 2 / g, preferably greater than 50 m 2 / g (determined by STSA - statistical thickness surface area according to ISO18852:2005).

[0210] The carbon black can be, for example, N234, N326, N330, N375, N550 or N660 sold by Birla Group (India) or CRX 1391 sold by Cabot Corporation.

[0211] The reinforcing filler may include a mixture, for example, a mixture of carbon black and silica.

[0212] In this way, it is possible to advantageously achieve optimal support during cornering and optimal traction during acceleration to manage the torque generated by a high-performance motorcycle (e.g., a super motorcycle of the previous generation).

[0213] The above elastomeric composition and the elastomeric compositions of the other components of the tire 1 can be vulcanized according to known techniques, in particular using sulfur-based vulcanization systems commonly used for elastomeric polymers. For this purpose, in the elastomeric composition, after one or more thermomechanical treatment steps, a sulfur-based vulcanizing agent is incorporated together with a vulcanization accelerator. In the final step of the treatment, the temperature is generally maintained below 140 °C to avoid any unwanted pre-crosslinking phenomenon.

[0214] The most advantageously used vulcanizing agent is sulfur or a sulfur-containing molecule (sulfur donor), which has accelerators and activators known to those skilled in the art.

[0215] Particularly effective activators are: zinc-based compounds, in particular ZnO, ZnCO 3 , zinc salts of saturated or unsaturated fatty acids containing 8 to 18 carbon atoms (e.g., zinc stearate), said zinc salts of saturated or unsaturated fatty acids being preferably formed in situ in the elastomeric composition from ZnO and fatty acids; and BiO, PbO, Pb 3 O 4 , PbO 2 or mixtures thereof.

[0216] Commonly used accelerators can be selected from: dithiocarbamates, guanidines, thioureas, thiazoles, sulfonamides, thiurams, amines, xanthates or mixtures thereof.

[0217] The elastomeric compositions used can include other additives, which are generally selected according to the specific use of each composition.

[0218] For example, the following additives can be added to the elastomeric composition: antioxidants, anti-aging agents, plasticizers, adhesives, anti-ozone agents, modified resins, fibers (aromatic polyamides or fibers of natural origin) or mixtures thereof.

[0219] In Table 1 below, for illustrative purposes only, an example of a rubber compound is given, which after vulcanization forms the first, second and third vulcanized elastomeric materials in a preferred embodiment of the tire 1.

[0220] The amounts of the various components in the elastomeric composition are generally provided in phr as defined above.

[0221] Table 1

[0222]

[0223]

[0224] * phr of dry polymer without extender oil

[0225] S-SBR: Solution-polymerized styrene-butadiene copolymer (phr given on dry polymer basis, 37.5 phr of TDAE oil added per 100 phr of dry elastomeric polymer) - TUFDENE E680 (Asahi Kasei)

[0226] E-SBR: Emulsion-polymerized styrene-butadiene copolymer (phr given on dry polymer basis, 37.5 phr of RAE oil added per 100 phr of dry elastomeric polymer) - INTOL 1789 (Versalis)

[0227] BR: Functionalized low-cis polybutadiene - YB03 (Asahi Kasei)

[0228] CB: CRX TM 1391 (Cabot)

[0229] Silica: 7000 (Evonik)

[0230] Liquid copolymer (grip enhancer): Low molecular weight butadiene / styrene liquid copolymer (4500 g / mol) - 100 (Cray Valley)

[0231] Extender oil: TDAE (Orgkhim)

[0232] Lubricant: Tris(2-ethylhexyl) phosphate (TOF) (Lanxess)

[0233] Resin 1: Hydrocarbon resin - 5140LV (Eastman)

[0234] Resin 2: Hydrocarbon resin - TT 90 (Lanxess)

[0235] Resin 3: Hydrocarbon resin - TT 30 (Reutgers Germany GmbH)

[0236] Zinc salt: Zinc neodecanoate 50 (Rhein Chemie)

[0237] Stearic acid: Stearic acid (Undesa)

[0238] Zinc oxide: ZnO (Zincol Ossidi)

[0239] Silane: SILAN (Evonik)

[0240] Zinc stearate: ACID GRAS SARE DE ZINC (Eigenmann & Veronelli)

[0241] Wax: WAX (Repsol)

[0242] Antioxidant: 2,2,4 - trimethyl - 1,1 - dihydroquinoline - TMQ (Lanxess)

[0243] Antiozonant: N - (1,3 - dimethylbutyl) - N’ - phenyl - p - phenylenediamine - 6PPD (Eastman)

[0244] Sulfur: IS 90P (Rhein Chemie)

[0245] Crosslinking agent: Bifunctional 1,6 - bis(NN’ - dibenzylthiocarbamoyl disulfide) - hexane - KA 9188 (Lanxess)

[0246] Adhesion promoter: Sodium hexamethylene - 1,6 - bis(thiosulfate) dihydrate salt - HTS (Eastman)

[0247] Vulcanization accelerator 1: N - tert - butylbenzothiazole sulfenamide - TBBS (Huatai Chemicals)

[0248] Vulcanization accelerator 2: Dibenzothiazole disulfide - MBTS 80 (Rhein Chemie)

[0249] Vulcanization accelerator 3: Tetrabenzylthiuram disulfide - TBZTD (Akrochem)

[0250] Vulcanization retarder: N - (cyclohexylthio)phthalimide - PVI (Akrochem)

[0251] According to the present invention, the dynamic elastic modulus E’ of the first vulcanized elastomeric material of the central sub - part 11a of the radially outer part 11 of the tread band 8, measured at a frequency of 10 Hz and a temperature of 23°C, is greater than the dynamic elastic modulus E’ of the second vulcanized elastomeric material of the lateral sub - parts 11b, 11c, measured at a frequency of 10 Hz and a temperature of 23°C.

[0252] Furthermore, the corresponding dynamic elastic moduli E’ of the first vulcanized elastomeric material of the central sub - portion 11a and the second vulcanized elastomeric materials of the lateral sub - portions 11b, 11c of the radially outer portion 11 of the tread band 8 are between 5.2 MPa and 6.5 MPa, preferably between 5.8 MPa and 6.4 MPa, when measured at a frequency of 10 Hz and a temperature of 23 °C.

[0253] Still according to the present invention, the dynamic elastic modulus E’ of the third vulcanized elastomeric material of the radially inner portion 12 of the tread band 8, when measured at a frequency of 10 Hz and a temperature of 23 °C, is less than the dynamic elastic modulus E’ of the aforementioned first vulcanized elastomeric material of the central sub - portion 11a and the aforementioned second vulcanized elastomeric materials of the lateral sub - portions 11b, 11c of the radially outer portion 11 of the tread band 8, when measured at a frequency of 10 Hz and a temperature of 23 °C.

[0254] As described above, the applicant believes that under the "cold" operating conditions of the tire 1, the third vulcanized elastomeric material in the radially inner portion 12 of the tread band 8 undergoes deformations (related to the elastic modulus E’) and hysteresis phenomena (related to the tanδ parameter) (at the lateral or shoulder portions of the tire), and these deformations and hysteresis phenomena allow the overlying radially outer portion 11 of the tread band 8 (which is harder and has less hysteresis) to be "heated", so that the overlying radially outer portion adheres better to the ground under wet and / or cold conditions.

[0255] According to the present invention, the ratio R1 between the dynamic elastic modulus E’ of the second vulcanized elastomeric material of the lateral sub - portions 11b, 11c of the radially outer portion 11 of the tread band 8, when measured at a frequency of 10 Hz and a temperature of 100 °C, and the dynamic elastic modulus E’ of the third vulcanized elastomeric material of the radially inner portion 12 of the tread band 8, when measured at a frequency of 10 Hz and a temperature of 70 °C, is between 0.8 and 1.2, preferably between 0.9 and 1.1.

[0256] Furthermore, the ratio R2 between the tanδ of the second vulcanized elastomeric material of the lateral sub - portions 11b, 11c of the radially outer portion 11 of the tread band 8, when measured at a frequency of 10 Hz and a temperature of 100 °C, and the tanδ of the third vulcanized elastomeric material of the radially inner portion 12 of the tread band 8, when measured at a frequency of 10 Hz and a temperature of 70 °C, is between 0.8 and 1.2, preferably between 0.9 and 1.1.

[0257] As described above, the applicant has observed through experiments that by controlling the values of the above-mentioned ratio R1 between the deformation characteristics related to the value of the dynamic elastic modulus E' and the ratio R2 between the hysteresis characteristics related to the value of tanδ to be close to 1, under the "hot" usage conditions of the tire, it is possible to advantageously have an optimal dynamic and hysteresis behavior in the shoulder region, thereby limiting premature wear and performance degradation phenomena, and also to advantageously have an optimal dynamic and hysteresis behavior in the central region, thereby ensuring optimal straight-line driving performance.

[0258] The tire 1 may also be provided with one or more of the above-mentioned preferred features, thereby achieving corresponding advantageous technical effects.

[0259] The present invention will now be illustrated by means of some examples, which are for illustrative purposes only and not for limiting purposes.

[0260] Properties of the Vulcanized Elastomer Composition

[0261] In Table 2 below, examples of rubber compounds are given for illustrative purposes only, which are made into the first, second, and third vulcanized elastomeric materials in a particularly preferred embodiment of the tire 1 after vulcanization.

[0262] The amounts of the various components in the elastomeric composition are generally provided in phr as defined above.

[0263] Table 2

[0264]

[0265]

[0266] * phr of dry polymer without extender oil

[0267] S-SBR: Solution-polymerized styrene-butadiene copolymer (phr given as dry polymer, 37.5 phr of TDAE oil added per 100 phr of dry elastomeric polymer) - TUFDENE E680 (Asahi Kasei)

[0268] E-SBR: Emulsion-polymerized styrene-butadiene copolymer (phr given as dry polymer, 37.5 phr of RAE oil added per 100 phr of dry elastomeric polymer) - INTOL 1789 (Versalis)

[0269] BR: Functionalized low-cis polybutadiene - YB03 (Asahi Kasei)

[0270] CB: CRX TM 1391 (Cabot)

[0271] Silica: 7000 (Evonik)

[0272] Liquid copolymer: Low molecular weight butadiene / styrene liquid copolymer (4500 g / mol)- 100 (Cray Valley)

[0273] Extender oil: TDAE (Orgkhim)

[0274] Lubricant: Tris(2-ethylhexyl) phosphate (TOF) (Lanxess)

[0275] Resin 1: Hydrocarbon resin- 5140LV (Eastman)

[0276] Resin 2: tert-Butylphenol resin (BASF)

[0277] Resin 3: Hydrocarbon resin- TT 90 (Lanxess)

[0278] Zinc salt: Zinc neodecanoate 50 (Rhein Chemie)

[0279] Stearic acid: Stearic acid (Undesa)

[0280] Zinc oxide: ZnO (Zincol Ossidi)

[0281] Silane: SILAN (Evonik)

[0282] Zinc stearate: ACID GRAS SARE DE ZINC (Eigenmann&Veronelli)

[0283] Wax: WAX (Repsol)

[0284] Antioxidant: 2,2,4-Trimethyl-1,1-dihydroquinoline - TMQ (Lanxess)

[0285] Antiozonant: N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine- 6PPD (Eastman)

[0286] Sulfur: IS 90P (Rhein Chemie)

[0287] Crosslinking agent: Bifunctionalized 1,6-bis(NN'-dibenzylthiocarbamoyl disulfide)-hexane- KA 9188 (Lanxess)

[0288] Adhesion promoter: Sodium hexamethylene-1,6-bis(thiosulfate)dihydrate salt- HTS (Eastman)

[0289] Vulcanization accelerator 1: N-tert-butylbenzothiazole sulfenamide - TBBS (Huatai Chemicals)

[0290] Vulcanization accelerator 2: Dibenzothiazole disulfide- MBTS 80 (Rhein Chemie)

[0291] Vulcanization accelerator 3: N-tert-butylbenzothiazole sulfenamide - TBBS 80 (Rhein Chemie)

[0292] Vulcanization retarder: N-(cyclohexylthio)phthalimide - PVI (Akrochem)

[0293] Table 3 below shows the results of static and dynamic mechanical analyses of samples of the compositions of three materials for the radially inner part 12 and the radially outer part 11 of the tread band 8 of the tire 1 according to the invention, the formulations of which have been indicated in Table 1 above.

[0294] These analyses were carried out under temperature and frequency conditions and according to the above techniques.

[0295] Table 3

[0296]

[0297]

[0298] Table 4 below shows the ratios between various vulcanized elastomeric materials and between the above-mentioned dynamic mechanical properties of the elastic modulus E’ and tanδ in each vulcanized elastomeric material, provided that the object of the invention is met.

[0299] Table 4

[0300]

[0301] It can be clearly seen from Table 4 that the values of the ratios R1, R2, R5 and R6 are equal to or close to 1, indicating a homogeneous behavior between the second and third vulcanized elastomeric materials (i.e., between the rubber composites present in the radially outer part and the radially inner part of the shoulder region of the tire 1) under both "hot" and "cold" conditions.

[0302] It can also be clearly seen from Table 4 that the "hot" values of the ratios R3 and R4 of tanδ and dynamic elastic modulus E' between the first vulcanized elastomeric material present in the central sub - part of the radially outer portion of the tread band of tire 1 and the third vulcanized elastomeric material present in the radially inner portion indicate a sufficiently differentiated behavior between these materials, i.e., the base portion of the tread band has greater deformation and hysteresis behavior, while the central sub - part of the radially outer portion of the tread band has greater rigidity and less hysteresis behavior.

[0303] In this way and as described above, such vulcanized elastomeric materials allow the tire to achieve optimal "hot" handling and grip performance during straight - line travel.

[0304] Finally, it can be clearly seen from Table 4 that the "cold" values of the ratios R7 and R8 of dynamic elastic modulus E' and tanδ between the first vulcanized elastomeric material present in the central sub - part of the radially outer portion of tire 1 and the third vulcanized elastomeric material present in the radially inner portion indicate a sufficiently differentiated behavior between these materials, i.e., the base portion of the tread band has greater deformation and hysteresis behavior, while the central sub - part of the radially outer portion of the tread band has greater rigidity and less hysteresis behavior.

[0305] In this way and as described above, such vulcanized elastomeric materials allow the tire to achieve optimal "cold" handling and grip performance during straight - line travel.

[0306] Tire Outdoor Test

[0307] To seek improved performance, the applicant used the Pirelli Diablo Rosso TM IV 190 / 55ZR17 rear tire as the basis for a comparative driving test. This tire has proven to be and still is a benchmark tire highly regarded by sport users.

[0308] Selecting to conduct the test on the rear tire is considered particularly stringent because during sporty driving, the rear tire is subjected to greater thermal stress compared to the front tire.

[0309] Both the tire according to the present invention and the comparative tire have a tread band with a "crown - base" configuration. The difference is that the comparative tire has a configuration of two different vulcanized elastomeric materials, i.e., a first elastomeric material in the lateral sub - part of the radially outer portion of the tread band and a second elastomeric material in the central sub - part of the radially outer portion of the tread band and in the radially inner portion of the tread band.

[0310] The tire according to the present invention has a configuration of three different vulcanized elastomeric materials, two of which are in the radially outer portion and one in the radially inner portion, as shown above with reference to Figure 2 shown.

[0311] Manufacture the radial inner part and the radial outer part of the tread of a rear-wheel super-sports tire similar in size to the comparative tire using the rubber compounds given in Table 2 and the mechanical properties given in Tables 3 and 4.

[0312] The tread of the crown base type of the comparative tire is made of two materials given in Table 5 below (the composition is as previously indicated in Table 2, where applicable).

[0313] Table 5 (Comparative Tire)

[0314]

[0315]

[0316] * phr of dry polymer without extender oil

[0317] Different test tasks were carried out on a private track, and the grip and handling on both dry and wet surfaces were tested by performing a series of maneuvers. The driver's evaluations represent the average of the evaluations made during various maneuvers.

[0318] The test conditions for the dry surface are as follows. Tire inflation pressure: 2.5 bar; track asphalt temperature: 39 °C; air temperature: 18 °C.

[0319] The test conditions for the wet surface are as follows. Tire inflation pressure: 2.9 bar; track asphalt temperature: 8 °C; air temperature: 8 °C.

[0320] The test was carried out using the "super-sports" type motorcycle model BMW S1000 R.

[0321] Tables 6 and 7 below summarize the scores given by the testers for various performance types required for the tested tires in the dry and wet surface tests, respectively.

[0322] In addition, in the dry surface test, both a single-lap test (columns 1 and 2 of Table 6) and a 20-lap track test (columns 3 and 4 of Table 6) were carried out on different groups of tires according to the present invention and comparative tires to verify, in the second case, the performance degradation due to high-intensity use ("hard maneuvers") during a race or several training tasks (traveling approximately 100 km) on a simulated track.

[0323] Table 5 shows that for the tires according to the present invention, the symbol "=" is used to evaluate the same performance as the comparative tire, and the symbol "+" indicates an improvement relative to the comparative tire. As the performance improvement increases, the number of symbols "+" increases.

[0324] It should be noted that only the evaluations between the 1st column and the 2nd column (single lap) and between the 3rd column and the 4th column (after 20 laps of the track) are homogeneous. In other words, the set of tires used for the single lap evaluation is not the same set of tires as those used in the race simulation test, and this single lap is not the first lap of the race simulation.

[0325] Table 6 (Tests on dry ground)

[0326]

[0327] Table 7 (Tests on wet ground - single lap)

[0328]

[0329]

[0330] From the evaluation results given in Table 6 and Table 7, it can be clearly seen that the tires according to the present invention allow the achievement of the desired dual purpose, that is, to improve and maintain the handling and performance of the tires for as long as possible under "hot" usage conditions without compromising the handling and grip performance of the tires under the above-mentioned "cold" usage conditions.

[0331] Surprisingly, despite the use of a "soft" vulcanized elastomeric material in the radially inner part of the tread band (obviously less suitable for this type of driving conditions), the effect of improving and maintaining the handling and performance of the tires under "hot" usage conditions over time has still been achieved.

[0332] During the tests conducted, it was also noted that the single lap time of the tires according to the present invention on the test track was significantly shortened.

[0333] Various modifications can be made to the embodiments described in detail, and these modifications still fall within the protection scope of the present invention defined by the following claims.

Claims

1. A motorcycle tire (1), comprising an equatorial plane (X-X) and a tread band (8), said tread band comprising: a) a radially outer portion (11), said radially outer portion comprising: a1) a central sub-portion (11a), said central sub-portion being arranged across said equatorial plane (X-X) of said motorcycle tire and made of a first vulcanized elastomeric material, and a2) a pair of lateral sub-portions (11b, 11c), said pair of lateral sub-portions being located distally with respect to said equatorial plane (X-X) of said motorcycle tire (1) and arranged on opposite sides of said central sub-portion (11a), said lateral sub-portions (11b, 11c) being made of a second vulcanized elastomeric material; wherein, the dynamic elastic modulus (E’) of said first vulcanized elastomeric material of said central sub-portion (11a) measured at a frequency of 10 Hz and a temperature of 23°C is greater than the dynamic elastic modulus (E’) of said second vulcanized elastomeric material of said lateral sub-portions (11b, 11c) measured at a frequency of 10 Hz and a temperature of 23°C; wherein, the respective dynamic elastic moduli (E’) of said first vulcanized elastomeric material of said central sub-portion (11a) and said second vulcanized elastomeric material of said lateral sub-portions (11b, 11c) measured at a frequency of 10 Hz and a temperature of 23°C are between 5.2 MPa and 6.5 MPa; b) a radially inner portion (12), said radially inner portion extending along its entire axial extent below said radially outer portion (11) of said tread band (8), said radially inner portion (12) being made of a third vulcanized elastomeric material, the dynamic elastic modulus (E’) of said third vulcanized elastomeric material measured at a frequency of 10 Hz and a temperature of 23°C being less than the dynamic elastic modulus (E’) of said first vulcanized elastomeric material of said central sub-portion (11a) of said radially outer portion (11) of said tread band (8) and the dynamic elastic modulus (E’) of said second vulcanized elastomeric material of said lateral sub-portions (11b, 11c) of said radially outer portion (11) of said tread band (8); wherein, the ratio R1 between the dynamic elastic modulus (E’) of said second vulcanized elastomeric material of said lateral sub-portions (11b, 11c) of said radially outer portion (11) of said tread band (8) measured at a frequency of 10 Hz and a temperature of 100°C and the dynamic elastic modulus (E’) of said third vulcanized elastomeric material of said radially inner portion (12) of said tread band (8) measured at a frequency of 10 Hz and a temperature of 70°C is between 0.8 and 1.2; and wherein, the ratio R2 between the tanδ of said second vulcanized elastomeric material of said lateral sub-portions (11b, 11c) of said radially outer portion (11) of said tread band (8) measured at a frequency of 10 Hz and a temperature of 100°C and the tanδ of said third vulcanized elastomeric material of said radially inner portion (12) of said tread band (8) measured at a frequency of 10 Hz and a temperature of 70°C is between 0.8 and 1.

2.

2. The motorcycle tire (1) according to claim 1, wherein, the corresponding dynamic elastic moduli (E’) of the first vulcanized elastomeric material of the central sub - portion (11a) and the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) are between 5.8 MPa and 6.4 MPa when measured at a frequency of 10 Hz and a temperature of 23°C.

3. The motorcycle tire (1) according to claim 1, wherein, the ratio R1 is between 0.9 and 1.

1.

4. The motorcycle tire (1) according to claim 1, wherein, the ratio R2 is between 0.9 and 1.

1.

5. The motorcycle tire (1) according to claim 1, wherein, the dynamic elastic modulus (E’) of the first vulcanized elastomeric material of the central sub - portion (11a) of the radially outer portion (11) of the tread band (8) is between 5.1 MPa and 5.5 MPa when measured at a frequency of 10 Hz and a temperature of 70°C.

6. The motorcycle tire (1) according to claim 5, wherein, the dynamic elastic modulus (E’) of the first vulcanized elastomeric material of the central sub - portion (11a) of the radially outer portion (11) of the tread band (8) is between 5.2 MPa and 5.4 MPa when measured at a frequency of 10 Hz and a temperature of 70°C.

7. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the tanδ of the first vulcanized elastomeric material of the central sub - portion (11a) of the radially outer portion (11) of the tread band (8) is between 0.26 and 0.30 when measured at a frequency of 10 Hz and a temperature of 70°C.

8. The motorcycle tire (1) according to claim 7, wherein, the tanδ of the first vulcanized elastomeric material of the central sub - portion (11a) of the radially outer portion (11) of the tread band (8) is between 0.27 and 0.29 when measured at a frequency of 10 Hz and a temperature of 70°C.

9. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the dynamic elastic modulus (E’) of the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) of the radially outer portion (11) of the tread band (8) is between 2.5 MPa and 2.9 MPa when measured at a frequency of 10 Hz and a temperature of 100°C.

10. The motorcycle tire (1) according to claim 9, wherein, the dynamic elastic modulus (E’) of the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) of the radially outer portion (11) of the tread band (8) is between 2.6 MPa and 2.8 MPa when measured at a frequency of 10 Hz and a temperature of 100°C.

11. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, The tanδ of the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) of the radially outer portion (11) of the tread band (8) is between 0.24 and 0.28 when measured at a frequency of 10 Hz and a temperature of 100 °C.

12. The motorcycle tire (1) according to claim 11, wherein, The tanδ of the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) of the radially outer portion (11) of the tread band (8) is between 0.25 and 0.27 when measured at a frequency of 10 Hz and a temperature of 100 °C.

13. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, The dynamic elastic modulus (E’) of the third vulcanized elastomeric material of the radially inner portion (12) of the tread band (8) is between 2.5 MPa and 2.9 MPa when measured at a frequency of 10 Hz and a temperature of 70 °C.

14. The motorcycle tire (1) according to claim 13, wherein, The dynamic elastic modulus (E’) of the third vulcanized elastomeric material of the radially inner portion (12) of the tread band (8) is between 2.6 MPa and 2.8 MPa when measured at a frequency of 10 Hz and a temperature of 70 °C.

15. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, The tanδ of the third vulcanized elastomeric material of the radially inner portion (12) of the tread band (8) is between 0.25 and 0.29 when measured at a frequency of 10 Hz and a temperature of 70 °C.

16. The motorcycle tire (1) according to claim 15, wherein, The tanδ of the third vulcanized elastomeric material of the radially inner portion (12) of the tread band (8) is between 0.26 and 0.28 when measured at a frequency of 10 Hz and a temperature of 70 °C.

17. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, The dynamic elastic modulus (E’) of the first vulcanized elastomeric material of the central sub - portion (11a) of the radially outer portion (11) of the tread band (8) is between 6.0 MPa and 6.5 MPa when measured at a frequency of 10 Hz and a temperature of 23 °C.

18. The motorcycle tire (1) according to claim 17, wherein, The dynamic elastic modulus (E’) of the first vulcanized elastomeric material of the central sub - portion (11a) of the radially outer portion (11) of the tread band (8) is between 6.2 MPa and 6.4 MPa when measured at a frequency of 10 Hz and a temperature of 23 °C.

19. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, The tanδ of the first vulcanized elastomeric material of the central sub - portion (11a) of the radially outer portion (11) of the tread band (8) is between 0.40 and 0.44 when measured at a frequency of 10 Hz and a temperature of 23 °C.

20. The motorcycle tire (1) according to claim 19, wherein, The tanδ of the first vulcanized elastomeric material of the central sub - portion (11a) of the radially outer portion (11) of the tread band (8) is between 0.41 and 0.43 when measured at a frequency of 10 Hz and a temperature of 23°C.

21. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the dynamic elastic modulus (E’) of the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) of the radially outer portion (11) of the tread band (8) is between 5.5 MPa and 6.0 MPa when measured at a frequency of 10 Hz and a temperature of 23°C.

22. The motorcycle tire (1) according to claim 21, wherein, the dynamic elastic modulus (E’) of the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) of the radially outer portion (11) of the tread band (8) is between 5.7 MPa and 5.9 MPa when measured at a frequency of 10 Hz and a temperature of 23°C.

23. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the tanδ of the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) of the radially outer portion (11) of the tread band (8) is between 0.66 and 0.70 when measured at a frequency of 10 Hz and a temperature of 23°C.

24. The motorcycle tire (1) according to claim 23, wherein, the tanδ of the second vulcanized elastomeric material of the lateral sub - portions (11b, 11c) of the radially outer portion (11) of the tread band (8) is between 0.67 and 0.69 when measured at a frequency of 10 Hz and a temperature of 23°C.

25. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the dynamic elastic modulus (E’) of the third vulcanized elastomeric material of the radially inner portion (12) of the tread band (8) is between 4.0 MPa and 5.0 MPa when measured at a frequency of 10 Hz and a temperature of 23°C.

26. The motorcycle tire (1) according to claim 25, wherein, the dynamic elastic modulus (E’) of the third vulcanized elastomeric material of the radially inner portion (12) of the tread band (8) is between 4.2 MPa and 4.5 MPa when measured at a frequency of 10 Hz and a temperature of 23°C.

27. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the tanδ of the third vulcanized elastomeric material of the radially inner portion (12) of the tread band (8) is between 0.49 and 0.53 when measured at a frequency of 10 Hz and a temperature of 23°C.

28. The motorcycle tire (1) according to claim 27, wherein, the tanδ of the third vulcanized elastomeric material of the radially inner portion (12) of the tread band (8) is between 0.50 and 0.52 when measured at a frequency of 10 Hz and a temperature of 23°C.

29. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, The ratio R3 between the tanδ measured at a frequency of 10 Hz and at 70 °C of the first vulcanized elastomeric material of the central sub - part (11a) of the radially outer part (11) of the tread band (8) and the tanδ measured at a frequency of 10 Hz and at 70 °C of the third vulcanized elastomeric material of the radially inner part (12) of the tread band (8) is between 0.5 and 1.

2.

30. The motorcycle tire (1) according to claim 29, wherein, the ratio R3 is between 0.7 and 1.

0.

31. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the ratio R4 between the dynamic elastic modulus (E’) measured at a frequency of 10 Hz and at 70 °C of the first vulcanized elastomeric material of the central sub - part (11a) of the radially outer part (11) of the tread band (8) and the dynamic elastic modulus (E’) measured at a frequency of 10 Hz and at 70 °C of the third vulcanized elastomeric material of the radially inner part (12) of the tread band (8) is between 1.3 and 2.

0.

32. The motorcycle tire (1) according to claim 31, wherein, the ratio R4 is between 1.5 and 1.

8.

33. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the ratio R5 between the dynamic elastic modulus (E’) measured at a frequency of 10 Hz and at 23 °C of the second vulcanized elastomeric material of the lateral sub - parts (11b, 11c) of the radially outer part (11) of the tread band (8) and the dynamic elastic modulus (E’) measured at a frequency of 10 Hz and at 23 °C of the third vulcanized elastomeric material of the radially inner part (12) of the tread band (8) is between 1.1 and 1.

6.

34. The motorcycle tire (1) according to claim 33, wherein, the ratio R5 is between 1.2 and 1.

5.

35. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the ratio R6 between the tanδ measured at a frequency of 10 Hz and at 23 °C of the second vulcanized elastomeric material of the lateral sub - parts (11b, 11c) of the radially outer part (11) of the tread band (8) and the tanδ measured at a frequency of 10 Hz and at 23 °C of the third vulcanized elastomeric material of the radially inner part (12) of the tread band (8) is between 1.1 and 1.

6.

36. The motorcycle tire (1) according to claim 35, wherein, the ratio R6 is between 1.2 and 1.

5.

37. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, The ratio R7 between the dynamic elastic modulus (E’) measured at a frequency of 10 Hz and a temperature of 23 °C of the first vulcanized elastomeric material of the central sub - part (11a) of the radially outer part (11) of the tread band (8) and the dynamic elastic modulus (E’) measured at a frequency of 10 Hz and a temperature of 23 °C of the third vulcanized elastomeric material of the radially inner part (12) of the tread band (8) is between 1.2 and 1.

8.

38. The motorcycle tire (1) according to claim 37, wherein, the ratio R7 is between 1.3 and 1.

7.

39. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the ratio R8 between the tanδ measured at a frequency of 10 Hz and a temperature of 23 °C of the first vulcanized elastomeric material of the central sub - part (11a) of the radially outer part (11) of the tread band (8) and the tanδ measured at a frequency of 10 Hz and a temperature of 23 °C of the third vulcanized elastomeric material of the radially inner part (12) of the tread band (8) is between 0.6 and 1.

1.

40. The motorcycle tire (1) according to claim 39, wherein, the ratio R8 is between 0.7 and 1.

0.

41. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the ratio R9 between the dynamic elastic modulus (E’) measured at a frequency of 10 Hz and a temperature of 23 °C of the third vulcanized elastomeric material of the radially inner part (12) of the tread band (8) and the dynamic elastic modulus (E’) measured at a frequency of 10 Hz and a temperature of 70 °C of the third vulcanized elastomeric material is between 1.2 and 2.

0.

42. The motorcycle tire (1) according to claim 41, wherein, the ratio R9 is between 1.4 and 1.

9.

43. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the ratio R10 between the tanδ measured at a frequency of 10 Hz and a temperature of 23 °C of the third vulcanized elastomeric material of the radially inner part (12) of the tread band (8) and the tanδ measured at a frequency of 10 Hz and a temperature of 70 °C of the third vulcanized elastomeric material is between 1.5 and 2.

4.

44. The motorcycle tire (1) according to claim 43, wherein, the ratio R10 is between 1.7 and 2.

1.

45. The motorcycle tire (1) according to any one of claims 1 to 6, wherein, the lateral curvature ratio of the motorcycle tire is equal to or greater than 0.

30.

46. The motorcycle tire (1) according to claim 45, wherein, the lateral curvature ratio of the motorcycle tire is between 0.30 and 0.35.

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