A tyre includes a tread portion including a tread surface which is provided with grooves. At least one of the grooves includes a widening-width portion at least partially. The widening-width portion includes a first groove portion extending inwardly in a tyre radial direction from the tread surface, and a second groove portion located inwardly in the tyre radial direction of the first groove portion and having a groove width greater than that of the first groove portion.

A pneumatic tire comprises at least four main grooves extending in the tire circumferential direction on the tread surface, circumferential land portions and shoulder land portions partitioned and formed by these main grooves, and designation of a mounting direction with respect to a vehicle, wherein a plurality of lug grooves is formed at intervals in the tire circumferential direction in each of the plurality of circumferential land portions, extending in the tire width direction, communicating with the main groove on the vehicle inner side, not communicating with the main groove on the vehicle outer side, and terminating within the circumferential land portion.

A TBR pneumatic tire of a driving wheel comprising a tread having a design such as to confer an average tread slip of less than 0.5 mm and a tread points slip range of between 0.07 mm and 1.17 mm. The tread is manufactured with a compound comprising a cross-linking unsaturated chain polymer base comprising from 40 to 80% by weight of a stirene-butadiene rubber (SBR), a filler comprising from 40 to 80% by weight of silica and a vulcanization system.

A pneumatic tire includes plural land portions that are provided at a tread and that are partitioned by plural circumferential direction grooves that extend along a tire circumferential direction. A lug groove is provided at at least one land portion among the plural land portions and crosses the land portion in a tire width direction. A fine groove is provided at a groove bottom portion of the lug groove, has a narrower groove width than the lug groove, and has a groove bottom face formed with a circular arc shaped profile when viewed in cross-section at right angles to a groove length direction. A coupling curved face joins the groove bottom face and a groove side face at a length direction end portion of the fine groove, to a groove side face of the circumferential direction grooves.

A tire includes a carcass, side-reinforcing rubber, a belt layer, and a tread. The belt layer includes at least two layers and is provided at a tire radial direction outer side of the carcass, each layer including a cord inclined with respect to a tire circumferential direction such that the cords of the belt layers intersect each other. The tread is provided at the tire radial direction outer side of the belt layer. A tire cross-section height SH satisfies SH≥145 mm, and a ground contact width TW of the tread and a maximum tire width direction width of the belt layer satisfies TW<B. Moreover, an angle θ formed between a tire outer face and the tire width direction at a position at 0.8SH toward the tire radial direction outer side of a bead base portion of either of the bead portions is no less than 60°.

In a pneumatic tire including a tread portion, a pair of side wall portions, and a pair of bead portions, a carcass layer is mounted between the bead portions, the tread portion has a multilayer structure including a cap tread rubber layer and an undertread rubber layer, and a snow traction index is 180 or more. A tread radius in a meridian cross-section of the tread portion falls within a range of from 80% to 140% of a tire outer diameter, a ground contact width of the tread portion falls within a range of from 66% to 83% of a tire cross-sectional width, and a height of a bead filler is 40% or less of a tire cross-sectional height.

A rubber composition for a tire according to an embodiment of the present technology includes: 100 parts by mass of a diene rubber and from 1 to 30 parts by mass of a thermally expandable microcapsule composite body, and the thermally expandable microcapsule composite body contains one or more thermally expandable microcapsules and an acrylonitrile butadiene copolymer and/or a crosslinked body thereof covering the one or more thermally expandable microcapsules.

In a pneumatic tire, an intermediate land portion is provided with a plurality of lug grooves having acute bent portions and a plurality of sipes extending in a direction that intersects with the lug grooves. The lug grooves are disposed so as not to overlap one another in the tire circumferential direction, and each have one end that opens to an outer main groove and an other end that terminates in the intermediate land portion. When pitches, which serve as reference positions, are defined based on end points at which the lug grooves open to the outer main groove, the sipes each are disposed to be located inside one of the pitches, and the groove area ratio in the pitches in the intermediate land portion is in the range from 15% to 25%.

An aerodynamically optimized drag-reduction appartus and method for optimal minimization of the drag-induced resistive forces upon a terrestrial vehicle, where the drag-induced resistive moments on wheel surfaces pivoting about the stationary point of ground contact are reduced, and the vehicle propulsive forces needed to countervail the resistive forces on the wheel are reduced. The drag reduction apparatus includes: a streamlined fairing or wind deflector positioned on a vehicle to shield the faster moving upper wheel surfaces from headwinds; an engine exhaust pipe disposed on a vehicle whereby exhaust gases deflect headwinds to shield the faster moving upper wheel surfaces of an automotive wheel; an automotive spoked wheel having streamlined oval-shaped wheel spokes; a wheel assembly with a streamlined tailfin rotatably attached to a wheel spoke; a wheel with a tapered spoke having a thin aerodynamic profile near the rim and tapering to a round profile toward the central hub; and a tire having streamlined tread blocks arranged in an aerodynamic pattern.

A pneumatic tire has a tread having adjacent rib-shaped land portions (4) with circumferential grooves (3) therebetween. Annular elongate projection portions (5, 5) project toward each other from adjacent rib-shaped land portions (4). The elongate projection portions (5, 5) confronting each other are disposed with a spacing therebetween such that their mutually confronting tip surfaces (5s, 5s) make contact with each other due to elastic deformation of the rib-shaped land portions (4, 4) at the time of grounding of the tire. An inside groove space (6) is formed on a radially inner side of the confronting elongate projection portions (5, 5) and an outside groove space (7) is formed on a radially outer side of the elongate projection portions (5, 5). The tip surfaces (5s) of the elongate projection portions (5) are formed with a plurality of communication recesses (9) providing communication between the inside and outside groove spaces (6, 7). The communication recesses (9) are formed at intervals in a tread circumferential direction. It is thus possible to enhance rigidity of the rib-shaped land portions over the whole tread at the time of grounding of the tire, thereby to suppress elastic deformation of the rib-shaped land portions and to reduce rolling resistance, while securing a draining property attributable to the circumferential grooves.