A tire includes a body ply sheet having a rubber core defined by a top surface having a length and a width, a bottom surface having substantially the same length and width, and side surfaces having a common height. The rubber core is further defined by a top rubber layer and a bottom rubber layer. The body ply sheet includes reinforcement cords disposed between the top rubber layer and the bottom rubber layer. The reinforcement cords are spaced 0.1-4.0 mm apart from each other and span the width of the body ply sheet. Bleeder cords are disposed on the body ply sheet and spaced 8-12 cm apart from each other. Conductive cords are also disposed on the body ply and spaced 20-80 cm apart from each other.

A tire tread may be formed by simultaneously extruding a tread cap formed of a first material and a tread base formed of a second material having a substantially different stiffness property than the first material. One tread element may have a strip of the second material extending from the tread base into the tread cap and, a second tread element may also have a strip of the second material extending from the tread base into the tread cap.

A tire tread may be formed by simultaneously extruding a tread cap formed of a first material and a tread base formed of a second material having a substantially different stiffness property than the first material. One tread element may have a strip of the second material extending from the tread base into the tread cap and, a second tread element may also have a strip of the second material extending from the tread base into the tread cap.

The collapse of conductive terminal rubber strips is prevented while a conductive terminal portion is formed stably to have an exposure width of 5 mm or less. The conductive terminal portion is formed by continuously winding the terminal strips formed of a conductive rubber toward an outward radial direction from a tread conductive layer to a tread ground contacting surface. The terminal strip is sequentially wound while shifting a position at a pitch D of a distance in a tire axial direction while the terminal strip goes around such that the conductive terminal portion constitutes a trapezoidal cross section in which a width (Wa) of an upper base is smaller than a width (Ws) of the terminal strip and a width (Wb) of a lower base is larger than the width (Ws) of the terminal strip. The width (Wa) of the upper base is within a range of between 2 mm and 5 mm.

In a process for building tyres for vehicle wheels, at least one tread band (9) or other elastomeric component of a tyre (2) is made by applying at least one continuous elongated element (14) according to a plurality of turns (C) around a forming drum (15) rotating around a geometric rotation axis (X) thereof. The continuous elongated element (14) is made by the action of extruding a first material through an extrusion nozzle (16), to form an inner core (33) of said continuous elongated element (14) exiting from an outlet opening (18) of the extrusion nozzle (16). During the extrusion, a second material different from the first material is conveyed around the first material, at the extrusion nozzle (16) and upstream of the outlet opening (18), to form a coating layer (32) which entirely surrounds the inner core (33).

The needle (12) of the device for inserting a wire into a tire has: a piercing zone (18) having an axis of symmetry, and a duct (30) having a proximal opening and a distal opening (36) opening into the zone (18) and off-center relative to the axis, the duct consisting of the proximal opening and of a rectilinear profiled section including the distal opening.

A pneumatic tire has a conductive portion formed by a conductive rubber is provided in the tread rubber formed by a nonconductive rubber. The conductive portion has an outer skin portion and a projection portion. The outer skin portion is formed on a surface of the tread rubber, and extends to an inner side in a tire width direction from a side surface of the tread rubber so as to terminate at a position which goes beyond a contact end. The projection portion spirally extends from a position in an outer side than contact end so as to reach a position in an inner side in the tire width direction than the contact end, and protrudes to an inner side in a tire diametrical direction from the outer skin portion so as to terminate without reaching a bottom surface of the tread rubber.

The invention relates to a vehicle tire comprising a tread portion and a package of reinforcement layers arranged underneath the tread portion. The tread portion comprises a tread base layer arranged underneath the tread layer, and at least one rubber member that extends in the radial direction of the tire from the ground contacting surface to the reinforcement package. The tread layer rubber composition has an electrical resistivity at room temperature of more than 108 ohm-cm, the tread base layer rubber composition of between 106 ohm-cm and 108 ohm-cm, the member rubber composition of less than 106 ohm-cm; and the rubber composition of at least one layer of the reinforcement package has a electrical resistivity at room temperature of less than 106 ohm-cm. The vehicle tire combines a low rolling resistance with improved conductivity to avoid build-up of static electricity.

A manufacturing method of a pneumatic tire comprises a forming step of a tread rubber which includes a two-shot stage of simultaneously winding a first rubber ribbon constructed by a nonconductive rubber, and a second rubber ribbon constructed by a nonconductive rubber. In the two-shot stage, the first rubber ribbon and the second rubber ribbon which are adjacent to each other are spirally wound in such a manner as to come into contact with each other, and a ribbon winding position passes through an L-shaped route. A conductive rubber is partly provided in the first rubber ribbon in the winding process when the ribbon winding position passes through the L-shaped route. A conductive portion which spirally and continuously extends to the tread end from the ground-contacting surface and intermittently appears in the tire meridian cross section is formed by the conductive rubber.

One or more embodiments of the present invention provide a method for forming a tread on a green carcass comprising the steps of providing a tire building drum having a carcass thereon, applying a strip of a base compound continuously over one half of the carcass forming a first layer of base compound from the centerline of the carcass to a first lateral edge, applying a first tread cap compound over the base compound, applying a strip of a base compound continuously over the second half of the carcass forming a second layer of base compound from the centerline of the carcass to a second lateral edge, forming a chimney along an edge of the first tread cap compound, and applying a first tread cap compound over the second layer of the base compound.