A process for the manufacture of a tread band for pneumatic tyres, wherein the blocks thereof comprise different rubber portions characterized by a different hysteresis loss. The process comprises a shredding step, wherein from a first and from a second rubber tread compound a plurality of fragments is manufactured with dimensions of between 6 and 30 mesh; a mixing step, wherein the fragments from the first and second compound are mixed together in order to obtain a mixture wherein said fragments are distributed in a random manner and retain their chemical/physical individuality; and an extrusion step, wherein the mixture from the preceding step is extruded for the manufacture of the tread band. The first and second compounds have different dynamic properties in terms of: dynamic modulus at 30° C., tand at 0° C., tand at 30° C. and tand at 60° C. The fragments retain a chemical/physical individuality both within the mixture formed during the mixing step and within the tread band formed during the extrusion step.

A tread of a tire can include a cap layer and a base layer. A loss tangent of the cap layer at 30° C. may be not greater than 0.30, and a loss tangent of the base layer at 30° C. may be less than the loss tangent of the cap layer at 30° C. The base layer can be inward of a reference end of the tread in an axial direction A fixing layer can be between the cap layer and a carcass in a radial direction. A first end of the fixing layer can be outward of an end of the base layer in the axial direction, or a position of the first end of the fixing layer can coincide with a position of the end of the base layer in the axial direction. Adhesiveness of the fixing layer can be higher than adhesiveness of the cap layer.

To provide a narrow and large-diameter tire capable of improving noise performance at high speeds without compromising handling performance at low temperatures.

The tire has a tread portion formed of an elastomer composition. A relationship between a tire outer diameter (Dt) and a tire cross-sectional width (Wt) satisfy a following expression (1). The tread portion includes at least one circumferential groove extending in a tire circumferential direction. A rubber thickness at a groove bottom of the circumferential groove is 0.05 to 0.25 times a maximum thickness of the tread portion. The elastomer composition has a phase difference δ of 5.0×10.sup.−2π [rad] or less between a maximum value of strain and a maximum value of stress when repeatedly deformed at a temperature of 30 degrees Celsius and a frequency of 10 Hz in a dynamic viscoelasticity test;

1963.4≤(Dt.sup.2×π/4)/Wt≤2827.4  (1).

A radial tire (10), with the sidewalls thereof (20), and the tread thereof (30) arranged for minimizing the temperature of the tire while guaranteeing its electrical conductivity. The tread (30) comprises two wings (311, 312) and a central portion (32). These components rest on a base layer (33) radially on the inside of the tread (30). The base layer (33) contains a lateral portion (331, 332) partly in contact with a tread wing (311, 312). This structure of the crown of the tire, in contact with the carcass reinforcement makes it possible to constitute a preferential conductive pathway of the electric charges between the rim and the ground when the tire is mounted on its rim and flattened on the ground.

The disclosure relates to tire tread compositions and methods for making. The compositions include a rubber, a rosin ester resin and at least one filler. The rosin ester resin is characterized as having a PAN number of less than 25, an acid number less than 20, a hydroxyl number of less than 30, a combined acid number and hydroxyl value of less than 50. The tire tread composition has a wet grip resistance to rolling resistance indicator ratio ((tan δ at 0° C.)/tan δ at 60° C.) higher than a tire tread composition containing a comparable amount of a rosin ester having a combined acid number and hydroxyl value of more than 50.

The introduction of graphene as an additive in truck tire treads is disclosed. The product shows increased electrical resistance in tire treads, with no tradeoffs in other characteristics.

The invention provides a pneumatic tire having a tire tread with a ground engaging outer surface. The tread further has a first or central tread zone located on the central or crown portion of the tread and formed of a first rubber compound. Additionally, the tread has a second or shoulder tread zone located axially outward of the first or central tread zone on each lateral end of the tread. The second or shoulder tread zone is formed of a second rubber compound. In one example, the first rubber compound has a G′ (at 50% strain) in the range of 1.6 to 1.8 MPa. In another example, the second rubber compound has a G′ (at 100% strain) in the range of 800 to 830 KPa.

A motorcycle tire includes a tread rubber that includes a base rubber layer and a cap rubber layer disposed outward in the tire radial direction of the base rubber layer to form a ground contact surface. The cap rubber layer includes a crown cap portion disposed in a middle region in the tire axial direction of a tread portion and a pair of shoulder cap portions disposed in both sides in the tire axial direction of the crown cap portion. The crown cap portion has a loss tangent tan δc, the shoulder cap portions have a loss tangent tan δs, and the base rubber layer has a loss tangent tan δb, wherein the loss tangents tan δc, tan δs and tan δb satisfy the following equation (1): tan δc<tan δs≤tan δb . . . (1).

To provide a pneumatic tire in which the rolling resistance coefficient is reduced while maintaining steering stability. A total gauge TOGa of a cap tread rubber (11A) and an undertread rubber (11B) and a gauge UTGa of the undertread rubber (11B) satisfy a relationship 0.20 ≤ UTGa/TOGa ≤ 0.40 in a ground contact region defined by a pair of shoulder main grooves (10B) located on both outermost sides in a tire width direction in a tread portion (1). A hardness UTHs of the undertread rubber (11B) is in a range of 62 or more and 67 or less. The hardness UTHs of the undertread rubber (11B) and a hardness CapHs of the cap tread rubber (11A) satisfy a relationship 0.90 ≤ CapHs/UTHs ≤ 1.20. A tan δ (60° C.) of the undertread rubber (11B) is less than 0.06.

A two-wheeled vehicle tyre includes a tread portion being provided with a belt layer and a tread rubber disposed radially outwardly of the belt layer. The belt layer includes steel cords oriented along a tyre circumferential direction. The tread rubber includes a cap rubber forming a tread surface and a base rubber disposed radially inwardly of the cap rubber, wherein 300% modulus (M300c) of the cap rubber is greater than 300% modulus (M300b) of the base rubber, and loss tangent (tan δc) of the cap rubber is smaller than loss tangent (tan δb) of the base rubber.