A tire having a tread with a plurality of blocks 12 provided with at least one sipe 22 extending from the contact face of said block, and having a width that can vary in the direction of its depth, and known as a complex sipe. The tread has a first layer of material 38 and at least one second layer of material 40 radially on the inside of the first layer, the first layer being formed in a first rubber composition and the second layer being formed in a second rubber composition different from the first composition. The complex sipe 22 and the grooves separating the blocks are formed entirely in the first layer of material 38. Laterally on each side of the complex sipe, the second layer of material 40 extends, when viewed in transverse section in the block, beyond the bottom 30 of the complex sipe in the direction of the contact face of the block.

A pneumatic tire is provided which has sufficiently reduced rolling resistance during high-speed running and which has sufficiently improved durability. In this pneumatic tire, which has a tread, at least one rubber layer forming the tread includes a rubber component containing styrene butadiene rubber and isoprene rubber, and is formed from a rubber composition with a loss tangent (30° C. tan δ) less than or equal to 0.14, measured under the conditions of 30° C., frequency 10 Hz, initial strain 5%, and dynamic strain rate 1%; defining Wt (mm) as the cross-section width, Dt (mm) as the outer diameter and virtual volume V (mm3) as the volume of the space occupied by the tire when said tire is installed on the standardized rim and has an internal pressure of 250 kPa, the pneumatic tire satisfies (Formula 1) and (Formula 2).

1600≤(Dt.sup.2×π/4)/Wt≤2827.4  (Formula 1)

[(V+1.5×10.sup.7)/Wt]≤2.88×10.sup.5  (Formula 2)

The present invention provides a pneumatic tire which is sufficiently reduced in the rolling resistance during high-speed travel, while having sufficiently improved chipping resistance. A pneumatic tire which has a tread part, wherein: at least one rubber layer that forms the tread part contains a rubber component that contains an isoprene rubber, a styrene butadiene rubber and a butadiene rubber, while containing more than 5 parts by mass but 25 parts by mass or less of carbon black relative to 100 parts by mass of the rubber component; and if Wt (mm) is the cross-sectional width of the tire, Dt (mm) is the outer diameter of the tire, and V (mm.sup.3) is the virtual volume that is the volume of the space occupied by the tire when this pneumatic tire is installed on a standardized rim and the internal pressure is 250 kPa, (formula 1) and (formula 2) are satisfied.

1700≤(Dt.sup.2×π/4)/Wt≤2827.4  (formula 1)

[(V+1.5×10.sup.7)/Wt]≤2.88×10.sup.5  (formula 2)

A radial tire (10) for a heavy vehicle of construction plant type, and more particularly, the sidewalls thereof (20), arranged to minimize the temperature of the tire while guaranteeing its electrical conductivity. The tread (30) comprises two tread wings (31) and a central portion (32). The bead layer (71), the elastomeric coating compound of the carcass layer (50), the second sidewall layer (22) and the tread wing (31) 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.

This invention discloses a tire tread comprising: (a) a first tread cap layer comprising a first rubber composition; and (b) a second tread cap layer arranged radially inside of the first tread cap layer comprising a second rubber composition; wherein at 0° C. the rebound resilience of the first rubber composition is within a range of 10% to 25%, the rebound resilience of the second rubber composition is within a range of 15% to 35% and is at least 5% lower than that of the second rubber composition; and wherein at 100° C. the rebound resilience of the first rubber composition is within a range of 45% to 65%, the rebound resilience of the second rubber composition is within a range of 60% to 75% and is at least 3% higher than that of the first rubber composition.

A heavy duty pneumatic tire 1 has provided in a buttress region 10 thereof a protrusion 11 extending in the tire circumferential direction. In a tire meridian cross-section, the maximum protrusion height h.sub.max of the protrusion 11 from an imaginary buttress surface J is 3.0 mm or greater and is in the range of 0.025-0.050 times a half tread width Wt. The cross-sectional area Sa of the protrusion 11 protruding from the imaginary buttress surface J is 20 mm.sup.2 or greater.

A pneumatic tire is provided with an electrically conductive portion at least extending continuously from a bead portion to a belt layer. The electrically conductive portion has a linear structure. The linear structure includes an electrically conductive linear member linearly formed of electrically conductive material with an electrical line resistivity of less than 1×10{circumflex over ( )}8 Ω/cm. The electrically conductive portion ensures an electrically conductive path from the bead portion to the belt layer.

A tire includes a tread portion including a ground contact surface, a first rubber layer made of a first cap rubber forming part of the ground contact surface, a second rubber layer made of a second cap rubber disposed radially inwardly of the first rubber layer, and at least one groove portion opening to the ground contact surface. The first cap rubber has a loss tangent tan δ1, and the second cap rubber has a loss tangent tan δ2 greater than the loss tangent tan δ1. The groove portion includes a first indicator in which a bottom of the groove portion locally raises, the first indicator having an outer surface in a tire radial direction. The radially outer surface of the first indicator substantially coincides with a first wear line that is parallel to the ground contact surface and passes through a radially outer surface of the second rubber layer.

A pneumatic tire comprises a carcass layer, a belt layer disposed on an outer side of the carcass layer in a tire radial direction, and a tread rubber disposed on the outer side of the belt layer in the tire radial direction. The belt layer formed by laminating an angle belt having a belt angle ≥45° and ≤70° in absolute values, a pair of cross belts, having belt angles of ≥10° and ≤45° in absolute values and having belt angles of mutually opposite signs, and a circumferential reinforcing layer having a belt angle within a range of ±5° with respect to a tire circumferential direction. A tread width TW and a cross-sectional width Wca of the carcass layer have a relationship such that 0.82≤TW/Wca≤0.92. A width Ws of the circumferential reinforcing layer and a cross-sectional width Wca of the carcass layer such that 0.60≤Ws/Wca≤0.70.

A tire having a tread comprising at least three radially superposed portions which comprise a radially external portion being made of a first rubber composition, a radially intermediate portion being made of a second rubber composition and a radially internal portion being made of a third rubber composition; wherein each of the rubber compositions is based on at least an elastomer matrix, a reinforcing filler and a crosslinking system based on sulphur; wherein the amount in phr of sulphur in the first rubber composition is lower than that in the second rubber composition, and wherein the amount in phr of sulphur in the second rubber composition is higher than that in the third rubber composition.