A tire has a cap rubber formed of nonconductive rubber and forms a ground surface, and a conductive portion provided in at least one side end portion of a pair of side end portions in both ends in a tire width direction. The conductive portion is formed of a conductive rubber, and reaches a side surface of the cap rubber from the ground surface through an inner portion of the cap rubber. The conductive portion is relatively small in a thickness in the ground surface and a side surface of the cap rubber, is relatively large in the maximum thickness of an intermediate portion between the ground surface and the side surface of the cap rubber, and is formed into a crescent shape which is curved into an outer side in a tire width direction and an outer side in a radial direction, in a tire meridian cross section.

Tread rubber forms a ground contact surface. When the ground contact surface is divided into two parts: a mounting inner side and a mounting outer side, the tread rubber has an inner cap part that forms an inner ground contact surface and is produced from non-conductive rubber, and an outer cap part that forms an outer ground contact surface. The inner cap part has a branched conductive part that is formed from conductive rubber ranging from the ground contact surface of a mounting outer end of the inner cap part to the side surface or bottom surface of a mounting inner end while branching off at a plurality of positions. The outer cap part does not have branched conductive rubber. The branched conductive part is formed from the conductive rubber with a rubber hardness different from that of the non-conductive rubber that forms the inner cap part.

Provided is a pneumatic tire comprising a carcass 1 as a skeletal structure composed of at least one carcass ply extending toroidally between a pair of bead portions 11, at least one layer of a belt 2 located on the outer side of the carcass in the tire radial direction of the crown portion. The tire is provided with a cushion rubber 13C and a tread rubber 13G forming a tread portion in turn on the outer side of the belt in the tire radial direction, and a composite fiber 3 containing a conductive fiber and a non-conductive fiber is extended at least from the pair of bead portions to portions in contact with the cushion rubber or a pair of belt under cushions, so as to expose the composite fiber to both surfaces of the carcass at the outer and inner sides of the tire.

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.

A radial tire (1) for a motor vehicle comprises a crown (2) comprising a tread (3) provided with at least a radially outer part (3a) intended to come into contact with the road; two non-stretchable beads (4), two sidewalls (5) connecting the beads (4) to the tread (3), a carcass reinforcement (6) passing into the two sidewalls (5) and anchored in the beads (4); a crown reinforcement or belt (7) positioned circumferentially between the radially outer part (3a) of the tread (3) and the carcass reinforcement (6); a radially inner elastomer layer (8) referred to as underlayer, which is positioned circumferentially between the radially outer part (3a) of the tread (3) and the carcass reinforcement (6), which comprises at least one thermoplastic elastomer which is a block copolymer comprising at least one elastomer block and at least one thermoplastic block, and which also comprises at least one conductive filler.

[Object] To provide a pneumatic tire 2 from which static electricity is easily discharged. [Solution] The tire 2 includes penetration portions 8, an under tread 6, a belt 16, a carcass 16, and clinches 12. The carcass 16 includes a large number of cords aligned with each other, and a conductive topping rubber. The electric resistance Rc of the carcass which is represented by the following mathematical formula is less than 1.010.sup.8.
Rc=/g/(23.14r)L10
In the mathematical formula, is the volume resistivity (.Math.cm) of the topping rubber of the carcass, g is the minimum thickness (mm) of the topping rubber, r is the distance (m) from the axis of the tire to an outer end, in the radial direction, of the clinch, and L is the length (m) of the carcass from an end of the reinforcing layer to the outer end, in the radial direction, of the clinch.

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.

The present invention is directed to a tire having a tread comprising two shoulder portions and a center portion axially between the two shoulder portions, wherein at least one of the shoulder portions comprises a first rubber composition and the center portion comprises a second rubber composition different from said first rubber composition. The first rubber composition has a shear storage modulus which is at least 10% lower than the shear storage modulus of the second rubber composition, and the second rubber composition has a glass transition temperature which is at least 5% higher than the glass transition temperature of the first rubber composition.