A process for building tyres for vehicle wheels includes: forming a tyre in process, the tyre including a belt structure and depositing a tread band in a position radially external to the belt structure by winding a continuous elongated element made of elastomeric material according to axially adjacent or partially overlapped coils. During the deposition of the tread band and on at least one of the coils already wound, a conductive liquid elastomeric compound is applied, the compound continuously extended between a radially outer surface of the tread band and a radially outer surface of the belt structure to generate electrically conductive paths and free zones.

Disclosed are various embodiments for sensing wear of a tire tread and for providing for electrostatic discharge of electrostatic charge buildup in a vehicle. Various sensor structures and electrostatic discharge structures are created using conductive rubber compositions and/or other elements to achieve tire tread wear sensing and discharge of electrostatic buildup. Such structures include conductors made of conductive rubber compositions, for example, having an uncured or cured electrical resistance at 23° C. less than about 10 KΩ when formed into a wire about 254 millimeters long and 2 millimeters in diameter.

A pneumatic tire is provided in the tread portion with a land portion including a conductive portion made of a conductive rubber. The conductive portion has a radially inner end electrically connected to a conductive tire internal structural to be connected to a wheel rim, and a radially outer end exposed in a ground contacting top surface of the land portion. The conductive portion extends from its radially inner end to outer end while inclining toward a first side surface of the land portion. The first side surface comprises a radially inner part, and a radially outer part extending radially outwardly from the radially inner part while inclining to the radially outer end of the conductive portion at an angle greater than the radially inner part.

A method for the cold retreading of a tyre (1) comprising the following steps: a removal step, during which the old, worn tread is removed from the tyre in order to expose an equatorial surface (2) of a casing (3) of the tyre (1); a deposition step, during which a cushion (4) and a pre-cured tread strip (6) provided with a tread pattern are deposited around the equatorial surface (2) of the casing (3); and a curing step, during which the cushion (4) arranged between the casing (3) and the pre-cured tread strip (6) is cured. The cushion (4) is manufactured with a compound comprising 1 to 30 phr of at least one conductive material chosen among graphite, graphene and a carbon black having a surface area which is greater than or equal to 300 m.sup.2/gr. The curing step comprises a connection step, during which said cushion (4) is connected to a heat or power source (S).

A pneumatic tire manufacturing method is provided in which winding collapse is prevented, there is no possibility of adverse effects on the FV, a current-carrying layer can be formed easily, and down-stitching can be dispensed with or minimized in the manufacture of SOT-structure pneumatic tires having a base-pen structure in the tread. This pneumatic tire manufacturing method involves: a step in which a sidewall, an inner liner, and a ply are bonded on a first molding drum, beads are set, and the tread side part that will form the current-carrying layer is formed on the side wall, forming a first cover; a step in which a breaker and band are bonded on a second molding drum and the tread center part is formed on the band, shaping the tread ring; a step in which the first cover is inserted inside of the tread ring and inflated to bond to the tread ring with pressure; and a step in which the sidewall is bonded to the lateral surface of the first cover, and the tread side part and the tread center part are bonded together.

A method for manufacturing a raw blank of a tyre includes using a calender to produce a ply. The calender includes two rollers with a gap situated therebetween. A ply that includes a first rubber material is formed in the gap of the calender, with a bead of the first rubber material being formed upstream of the gap. The bead and the gap of the calender are fed with a second rubber material, different from the first rubber material, to form at least one insert in the ply.

A pneumatic tire has a rubber member constructed by a rubber ribbon winding body formed by spirally winding a rubber ribbon. The rubber ribbon includes a composite rubber ribbon which is formed by a non-conductive rubber, and a conductive rubber partly covering the non-conductive rubber. The composite rubber ribbon has a flat cross sectional shape and is gradually reduced in its thickness toward both ends. The conductive rubber has a cross sectional area which is equal to or less than 3% of a cross sectional area of the composite rubber ribbon, and forms a surface in one side and a surface in the other side in both ends of the composite rubber ribbon. The composite rubber ribbons that are adjacent in the width direction are partly overlapped, and a conductive route is provided by the conductive rubber connected between the composite rubber ribbons.

A green tire includes a plurality of sheets of green rubber having a substantially circular shape, with each sheet having a tread region disposed along a circumference. A plurality of objects are sandwiched between adjacent sheets of green rubber in the tread region. Each object is constructed of a material selected from the group consisting of steel, polyester, nylon, carbon fiber, aramid, fiber glass, cotton, hemp, polyurethane and other plastic, other synthetic or natural fibers and other metal materials.

An application device for applying a conductive insert on a tyre being processed. The application device includes a supply device for supplying a conductive liquid elastomeric compound, and an applicator having a movable surface for being operatively coupled with the supply device and receiving the conductive liquid elastomeric compound. The movable surface is for being placed in contact with a rotating tyre being processed and for applying the conductive liquid elastomeric compound on at least one coil of axially adjacent and/or partially superimposed coils. The applicator generates depressions in the tyre in a pattern defined by elements in relief and fills the depressions in the tyre with the conductive liquid elastomeric compound to covering the elements as the depressions in the tyre are generated.

A method for forming a composite tread, the method comprising the steps of: forming a coextruded strip of a first compound and a second compound, wherein the first compound is a tread compound, and the second compound is formed from a second compound, wherein the tread is formed from winding the coextruded strip onto the tire building drum while varying the ratio of the first compound to the second compound