A tire having a tread portion that is provided with sipes. Four sipe segments of the sipe include a first sipe segment, a second sipe segment, a third sipe segment, and a fourth sipe segment. At least one of the first sipe segment and the third sipe segment includes, in the cross section orthogonal to the length direction, an oscillated portion which extends in the tire radial direction, while oscillating in the lateral direction orthogonal to the length direction.

In a tire meridian cross-section in a 5% internal pressure state of a heavy duty tire, a first radius of curvature of a first ground-contact surface profile of each of a center land portion, an inner region of a first middle block, an outer region of the first middle block, and a first shoulder block can be defined. In addition, a ratio (Wa/Da) of a groove width Wa to a groove depth Da of a center circumferential groove may not be larger than 0.25. Furthermore, a ratio (Lb/La) of a maximum length Lb in a tire axial direction to a maximum length La in a tire circumferential direction in the first middle block can be defined.

A tire includes a tread portion provided with a plurality of blocks. At least one of the plurality of blocks is provided with a sipe. The sipe extends in a sipe longitudinal direction to form a zigzag opening configuration on a ground contact surface of the at least one of the plurality of blocks. The sipe extends inwardly in a tire radial direction such that the zigzag opening configuration oscillates in the sipe longitudinal direction repeatedly with a total amplitude and a wavelength while maintaining the zigzag opening configuration. A half of the wavelength of the sipe is in a range of from 0.10 to 0.24 times a maximum depth of the sipe, and a slope of the half of the wavelength with respect to the total amplitude has an angle in a range of from 45 to 65 degrees.

A pneumatic tire that lowers a temperature of a tread portion by promoting heat dissipation thereof is provided. On a tread surface, a narrow groove is formed extending in a direction inclined with respect to a tire circumferential direction and having a width smaller than a depth, and an inflow portion opening to the tread surface is also formed on at least one of walls of the narrow groove facing each other in the tire circumferential direction.

A shear-controlled tire tread includes a plurality of narrow channels disposed generally perpendicular to a rolling direction. Each narrow channel includes a heel side, a toe side, and a valley connecting the heel side and the toe side, and a first plurality of ridges disposed on a heel side and a second plurality of ridges disposed on a toe side. The first plurality of ridges disposed on a heel side and the second plurality of ridges disposed on a toe side are offset and form interacting friction surfaces when a heel side of collapses toward a toe side or a toe side collapses toward a heel side.

A pneumatic tire includes blocks arranged in the tread center region that is X % (30≦X≦70) of the tread contact width TW with the tire equator C as center are formed elongated in the tire circumferential direction so that the block ratio is not less than 1.5. At least one end in the longitudinal direction of the sipes provided in the blocks connects to a longitudinal groove. A protrusion and a recess that can engage with each other are provided on the sipe wall surfaces that face each other constituting the sipes, at the end portion in the longitudinal direction of the sipes that connect with the longitudinal groove.

A tire includes a first circumferential main groove 11 and a second circumferential main groove 12 in a tread surface 1. A resonator 21 is formed in an intermediate land portion 20 partitioned between the first circumferential main groove and the second circumferential main groove. The resonator has an auxiliary groove 211 whose both ends terminate within the intermediate land portion. The groove depths D1 of the first and second circumferential main grooves are 50% or less of the groove widths W2 of the first and second circumferential main grooves, respectively. The groove depth D3 of the auxiliary groove of the resonator is 70% or more of the groove depth D1 of the first circumferential main groove.

Tread for a pneumatic tyre comprising a sipe having a sipe extension (L) and a sipe depth (P) along a direction of wear (U), wherein said sipe has at least two sections (S1, S2) along said direction of wear (U) having respective differentiated conformations, such that an intersection profile (P1, P2) between the sipe and a surface (T1, T2) parallel to the contact surface of the tread is different for each of said at least two sections (S1, S2), wherein at least one surface section (S1) of said at least two sections (S1, S2) has a depth (PS) that is variable along said sipe extension (L), said two sections (S1, S2) being connected by a transition section (S3) defining a transition line (TL) between the respective sections (S1, S2), said variable depth (PS) of said surface section, presenting a maximum depth (PSMAX) and a minimum depth (PSMIN), and wherein the surface section (SI) has a twisted configuration.

The tread comprises a plurality of blocks, each block being delimited by transverse or oblique grooves and circumferential grooves. Each block is provided with a sipe which has three branches. The branches have common ends. A first branch is oriented in a transverse or oblique direction. A second branch and a third branch each open when new into a transverse groove delimiting the block. The angle formed between the first and second branches is 100 to 125 degrees, and the angle formed between the first and the third branches is 100 to 125 degrees. After wear, each sipe represents between 45% and 70% of the total wearable thickness, such that the lengths of the three branches measured on the new tread surface, L1′, L2′, L3′ respectively, are shorter than the lengths L1, L2, L3 respectively measured on the tread surface when new.

A shear-controlled tire tread includes a plurality of narrow channels disposed generally perpendicular to a rolling direction. Each narrow channel includes a heel side, a toe side, and a valley connecting the heel side and the toe side, and a first plurality of ridges disposed on a heel side and a second plurality of ridges disposed on a toe side. The first plurality of ridges disposed on a heel side and the second plurality of ridges disposed on a toe side are offset and form interacting friction surfaces when a heel side of collapses toward a toe side or a toe side collapses toward a heel side.