In a pneumatic tire, a modulus at 300% elongation of a cap tread ranges from 3.0 Mpa to 7.0 Mpa, and the modulus at 300% elongation of an undertread ranges from 10.0 Mpa to 20.0 Mpa. Additionally, an earthing tread is made from a rubber material with a volume resistivity of 1×10{circumflex over ( )}7 Ω.Math.cm or less. The earthing tread is made from the same rubber material as the undertread and has an integral structure with the undertread.

The invention relates to a method for producing a tread (20), comprising the steps: extruding the tread (20), which has an outer side (22) and an inner side (24), opposite the outer side (22), and a carrying region (26) made of a carrying region rubber material and a guide strip (28) made of a guide strip rubber material, wherein the guide strip (28) extends from the outside (22) to the inside (24) and a specific electrical guide strip resistance (W.sub.28) of the guide strip rubber material is smaller than a specific electrical carrying region resistance of the carrying region rubber material. The steps according to the invention are: determining an electrical guide strip resistance (W.sub.28) of the guide strip (28) between the outer side (22) and the inner side (24) and outputting a warning signal when the electrical resistance (W) exceeds a specified maximum resistance (W.sub.28,max).

A method for manufacturing a tire includes a rubber layer forming step of helically wrapping non-conductive strip rubber supplied from an extruder around an outer circumferential side of a conductive case main body to form a plurality of rubber layers. The rubber layer forming step includes: a non-conductive strip rubber wrapping step of wrapping the non-conductive strip rubber around; and a conductive strip rubber wrapping step of superposing conductive rubber on the non-conductive strip rubber to wrap around as conductive strip rubber. The conductive strip rubber wrapping step includes: wrapping pieces of the conductive rubber around in a layered manner so as to overlap each other in a tire radial direction; and forming a conductive portion reaching up to a tire surface.

Aspects of the invention relate to a tire that includes a shoulder wedge arranged in a shoulder portion of the tire between the sidewall and the belt package, the shoulder wedge being at least partially inserted between the belt package and the carcass ply. The tread includes a tread chimney component extending from the shoulder wedge to the rolling surface. The overlay coat of the tire's belt package, the tread band except for the tread chimney component, the tread base and the tire sidewall are made from non-conductive rubber. A conductive path between the rolling surface and the rim is provided across the tread chimney component, the shoulder wedge, the carcass ply and the chafer portion.

A tire includes a circumferential tread disposed in a crown region of the tire and an undertread disposed below the circumferential tread. The tire also has a pair of bead regions, including a first bead region and a second bead region, and a body ply extending from the first bead region to the second bead region. The tire further has a pair of sidewalls, including a first sidewall extending between the first bead region and the circumferential tread and a second sidewall extending between the second bead region and the circumferential tread. The tire also has a sidewall antenna adjacent to the first sidewall. The sidewall antenna has a first end contacting the undertread and a second end contacting the body ply.

A tire includes a pair of beads and a crown region including a circumferential tread disposed radially above a circumferential belt. The tire further includes a pair sidewalls extending from the pair of beads to the crown region. A body ply wraps around the pair of beads and terminates in a pair of turn up ends in the crown region, below the middle 30% of the circumferential belt. A conductive substance is disposed along a strip of the body ply.

A modulus at 300% elongation of a cap tread ranges from 3.0 Mpa to 7.0 Mpa, a modulus at 300% elongation of a undertread ranges from 10.0 Mpa to 20.0 Mpa, and a modulus at 300% elongation of an earthing tread ranges from 10.0 Mpa to 20.0 Mpa. Additionally, an earthing tread is made from a rubber material with a volume resistivity of 1×10{circumflex over ( )}7Ω.Math.cm or less. The undertread includes a thickened portion in a region between the earthing tread and an edge portion of a block. The gauge of the undertread gradually increases from the earthing tread toward the edge portion of the block due to the thickened portion.

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 pneumatic tire includes a surface cord disposed on at least one of an outer surface, which is a surface of a carcass at a tire outer side, and an inner surface, which is a surface of the carcass at a tire inner side. The surface cord has conductivity and is disposed along a tire width direction from at least a region adjoining a bead to a tread. A plurality of the surface cords is disposed with a predetermined interval in a tire circumferential direction.

A pneumatic tire includes a tread portion including main grooves and land portions. In a cross-sectional view of the tire, one of the land portions includes a first edge, a second edge, a ground contact surface extending between the first edge and the second edge and having an arc-shaped profile protruding radially outwardly, and conductive portion made of conductive rubber. The conductive portion extends from a radially inner end to a radially outer end exposed at the ground contact surface with an inclination toward the first edge. The inner end is connected to a tire internal structural member to be electrically connected to a rim when the tire is mounted on the rim. On the ground contact surface, a central position of the outer end is located on a central position of the land portion in a tire axial direction, or on a side of the first edge.