Disclosed is a pneumatic tire including: in a tread surface of a tread portion, a pair of main grooves (center main groove and shoulder main groove) arranged side by side in a tire lateral direction and extending in a tire circumferential direction; land portions (middle land portion) defined by the main grooves; a plurality of lug grooves arranged side by side in the tire circumferential direction and bent and folded back, each of the lug grooves including one end communicating with the shoulder main groove, the other end terminating within the middle land portion, and a bending point in a middle of a path from one end to the other end; and sipes extending across the lug grooves, at least one side of the sipe with respect to the lug groove being formed in a zigzag shape.

A tire has a tread portion 2. The first middle land region 11 is provided with bend grooves 15 each having a first end 15a and a second end 15b. The first end 15a is connected to the first shoulder circumferential groove 5. The second end 15b is connected to one of the bend grooves 15 next in one of two opposite circumferential directions. Each bend groove 15 has two bent portions 16 and 17 at which the groove is bent. The bent angle θ1 at the first bent portion 16 is greater than the bent angle θ2 at the second bent portion 17.

In a tread portion of a pneumatic tire, a first sipe wall surface of a sipe includes at least two first peak portions and at least one first valley portion at each position of the sipe extension direction, which are bent in a wave-like shape to form surface recesses and protrusions along a sipe depth direction. The first valley portion is sandwiched between the two first peak portions in the sipe depth direction, and extends from one end of the sipe in the extension direction to the other end of the sipe in the extension direction. A recess depth of the first valley portion with respect to the two first peak portions gradually reduces. A position of at least one of the two first peak portions in the sipe depth direction and a position of the first valley portion in the sipe depth direction become gradually closer.

Tyre for vehicle wheels, comprising a tread band having a plurality of blocks, at least some of said blocks comprising at least one sipe (30) extending from an axially outer portion of the block up to an axially inner portion of the block along a predetermined trajectory and from a radially outer face of the block towards a radially inner portion of the block. The sipe (30) comprises, in any cross-section perpendicular to said predetermined trajectory, a main portion (400) having a first radial dimension and a first transversal dimension and, in a radially inner position with respect to the main portion (400) and adjacent to the radially inner portion of the block, a bottom portion (450) having a second radial dimension smaller than the first radial dimension and a second transversal dimension greater than the first transversal dimension. The second transversal dimension measured in a first cross-section of the sipe (30) taken at at least one of said axially outer portion of the block and said axially inner portion of the block is greater than the second transversal dimension measured in a second cross-section of the sipe (30) taken at a portion of the block axially arranged between said axially outer portion of the block and said axially inner portion of the block. The sipe (30) comprises an axially outer portion (83), an axially inner portion (84) and a central portion (82) defined between said axially outer portion (83) and said axially inner portion (84). The sipe (30) comprises, in said central portion (82), at least one area in which said predetermined trajectory is not rectilinear.

The present invention provides for a heavy truck tire tread (12) with a plurality of sipes (20) in the shoulder rib (18) that extend from the shoulder edge (14) to the shoulder groove (16). Each one of the sipes (20) has a bottom (28) with a teardrop (30) located at the bottom, and the bottom (28) does not extend the same depth in the thickness direction across the entire lateral length of the sipe (20). The bottom (28) at a middle of the sipe (20) extends for less of a depth in the thickness direction than does the bottom (28) at a shoulder edge (14) portion of the sipe (20) located outboard from the middle of the sipe (20) in the lateral direction. The bottom (28) at the middle of the sipe (20) extends for less of a depth in the thickness direction than does the bottom (28) at a shoulder groove (16) portion of the sipe (20) located inboard from the middle of the sipe (20) in the lateral direction.

In a tire having a specified mounting direction, groove area ratios Rin and Rout in ground contact regions on the vehicle inner and outer sides, respectively, satisfy Rin>Rout, average land portion areas Ain and Aout of intermediate regions Min and Mout on the vehicle inner and outer sides, respectively satisfy Ain<Aout, the number of blocks Nin, Nout in the intermediate regions Min, Mout, respectively, satisfy Nin≥1.5×Nout, total sipe lengths Sin, Sout in the intermediate regions Min, Mout, respectively, satisfy Sin<Sout, and sipes formed in the intermediate region Mout have a three-dimensional structure in a range of 70% or more of a sipe length.

In a tire with a specified mounting direction, groove area ratios Rin and Rout in ground contact regions on the vehicle inner and outer sides, respectively, satisfy Rin>Rout, average land portion areas Ain and Aout of intermediate regions Min and Mout on the vehicle inner and outer sides, respectively, satisfy Ain<Aout, the number of blocks Nin and Nout in the intermediate regions Min and Mout, respectively, satisfy Nin≥1.5×Nout, total sipe lengths Sin and Sout in the intermediate regions Min and Mout, respectively, satisfy Sin>Sout, and sipes formed in the intermediate region Min have a three-dimensional structure in a range of 70% or more of a sipe length.

A pneumatic tire includes, in a land portion, at least one circumferential sipe extending in the tire circumferential direction. At a first position, from the tread surface towards the sipe bottom, the sipe width gradually decreases from the tread surface to a first changing point and then gradually increases from the first changing point to the sipe bottom. At a second position, from the tread surface towards the sipe bottom, the sipe width gradually increases from the tread surface to a second changing point and then gradually decreases from the second changing point to the sipe bottom. The sipe width at the tread surface and at the sipe bottom gradually decreases in the tire circumferential direction from the first position towards the second position, and the sipe width in a tire radial intermediate portion gradually increases in the tire circumferential direction from the first position towards the second position.

A tire has a tread portion having a second middle land region which is provided with middle lateral grooves and circumferentially divided into middle blocks. Each middle block is provided with two first middle sipes extending from a second shoulder circumferential groove, and one second middle sipe disposed between the two first middle sipes. Each first middle sipe extends in a wavy manner in its depth direction. The second middle sipe extends straight in its depth direction. The second middle sipe extends from the second shoulder circumferential groove and is terminated within the second middle land region.

A pneumatic tire includes, on a tread surface, circumferential main grooves extending in the tread circumferential direction, and land portions defined between circumferential main grooves adjacent in a tread width direction among the circumferential main grooves or by the circumferential main grooves and tread edges. The land portions include widthwise sipes (or grooves) extending in the tread width direction, and each widthwise sipe (or groove) includes a tread surface side sipe (or groove) portion extending from the tread surface inward in a tire radial direction, a first branched sipe (or groove) portion branching and extending from the tread surface side sipe (or groove) portion inward in the tire radial direction, and second branched sipe (or groove) portions branching and extending from respective tire radial inner ends of the first branched sipe (or groove) portion inward in the tire radial direction.