A tread for a tire includes a plurality of circumferential ribs, at least one of the ribs having sipes extending in a zigzag manner as the sipes extend axially across the rib and also extending in a zigzag manner as the sipes project radially inward from a radially outer surface of the rib.

A pneumatic tire, having a plurality of sipes formed in land portions of a tread thereof so as to each extend in the tire width direction, characterized in that: in a cross section of the land portion orthogonal to the sipe extending direction, provided that an imaginary sipe main line links two ends in the tire radial direction of each sipe, at least two of the sipes are inclined sipes each having the sipe main line inclined with respect to the tire radial direction; each inclined sipe has inner bent portions each protruding with respect to the sipe main line with peaks positioned deeper than 20% of the sipe depth; and the sipe main line(s) of at least one of the inclined sipes are inclined in a direction opposite, with respect to the tire radial direction, to the sipe main line of any of the other inclined sipes.

A tire tread mold which allows more flexibility in the design of tread patterns and which reduces the risks of blades being damaged during molding operations is needed. Such a mold has a tread mold portion which is divided in into a plurality of mold segments having an inner face curved along the circumferential direction according to an arc angle , each of the mold segments including laterally extending blades forming projections from their inner face; wherein the mold segments have a first end portion, a second end portion and a central portion; wherein laterally extending blades of the central portion extend in the operating direction, and wherein laterally extending blades of the end portions are inclined blades that extend in a direction forming an angle with the operating direction, wherein with angle being less than half of angle .

A tread pattern of a pneumatic tire includes circumferential main grooves, a land portion defined by the circumferential main grooves in the lateral direction, and sipes at intervals in a circumferential direction, the sipes connecting the circumferential main grooves with each other. Each of the sipes has a peak-like shape protruding to a first side in the circumferential direction. When, in a profile cross-section of the tread portion taken along the lateral direction, an arc passing through two land portion edge points at which a tread surface of the land portion is connected with groove wall surfaces of the circumferential main grooves and having a center point positioned on the equator line is set to a standard profile line, a profile line formed by the tread surface of the land portion is a swelling profile line protruding outward of the standard profile line in a radial direction.

A pneumatic tire in which a mounting orientation to a vehicle is designated, includes: the at least four land portions include an outside shoulder land portion, an outside quarter land portion, an inside shoulder land portion and an inside quarter land portion. A total ground contact area of the outside shoulder land portion and the outside quarter land portion is larger than a total ground contact area of the inside quarter land portion and the inside shoulder land portion. The outside quarter land portion has a first circumferential sipe extending in a tire circumferential direction. On the first circumferential sipe, a chamfered first inclined surface portion extending in the tire circumferential direction is provided between a vehicle outside inner wall of the first circumferential sipe and s surface of the outside quarter land portion.

In particular embodiments, a tire tread includes one or more lateral sipes (26s) arranged within the tread (20). As each such lateral sipe (26s) extends outward from within the tread thickness (T20) and towards the outer, ground-engaging side (22) of the tread (20), the lateral sipe (26s) is inclined towards the intended direction (R) of tire rotation. The lateral sipe (26s) also has a width (W26) (thickness) configured to, at an unworn stage, close along at least a portion of the sipe depth during operation of a loaded tire, and being configured to, at a worn stage, remain open during operation of the loaded tire. The lateral sipe (26s) has a width-to-height ratio associating the sipe width (W26) to the sipe height, the width-to-height ratio equaling 1:10 to 1:40. Providing a plurality of these lateral sipes (26s) may result in improved consistency of tread wear performance over the life of the tread (20).

A tire according to this disclosure includes a rib-like or block-like land portion in contact with a road surface. The land portion includes a plurality of sipes. The end portion of the sipe positioned on the earlier contact side in contact with the road surface earlier as the tire rotates is opened to the side wall of the land portion. The end portion of the sipe positioned on the later contact side in contact with the road surface lately as the tire rotates terminates in the land portion.

A heavy truck tire directional tread is provided that has two successive asymmetrical sipes (14) in the longitudinal direction that share at least some of the same offset from a tread edge in the lateral direction. Each of the two asymmetrical sipes (14) has a body (28) and a tear drop (30). The surface of the bottom of the sipe (14) has a radius of curvature that is not the same along the entire surface of the bottom. The geometry of the sipes resists crack initiation and propagation and is governed by the equation R.sub.A.B-avg>1-4?R.sub.ref, wherein R.sub.a.B-avg is the average radius of a particular portion of the bottom of the sipe, and Rref is a reference radius of the bottom of the sipe.

The invention includes a tire tread having one or more lateral discontinuities (26), each discontinuity extending into the tread thickness along a non-linear path. The lateral discontinuity extends from a first terminal end (40) to a second terminal end (42), the first terminal end being located closest to an outer, ground-engaging side relative to the second terminal end. The non-linear path can be described as extending from a first portion (A1, A2, A3), to an intermediate portion (B1), and then to a third portion (C1) when extending towards the second terminal end. The first portion has a low average inclination angle, the intermediate portion has a negative average inclination angle, and the third portion has a positive average inclination angle, each angle being measured relative to the depthwise direction of the tread. A positive angle is angled in the direction of intended tire rotation (R) as the tread thickness extends outward towards the outer, ground-engaging side.

A tyre includes a tread portion including a land portion having a ground contact surface and at least one sidewall. The land portion is provided with a radial channel extending from a radially outer end opened at the ground contact surface to a radially inner end, an internal lateral channel extending under the ground contact surface within the land portion and having one end opened at the at least one sidewall and communicating with the radially inner end of the radial channel, and a sipe opened at the ground contact surface and communicating with the radial channel and the internal lateral channel. The radially outer end of the radial channel has an axial opening width in a range of from 5% to 20% of an axial width of the land portion.