The invention provides three-dimensional tread kerfs for a tire, which have improved braking performance and drainage characteristics on a wet road while maintaining the functions of kerfs on the snow. Disclosed are tread kerfs for a tire, each tread kerf having a kerf opening formed in a block of a tire tread; a tubular-shaped flow channel formed in the lower part of the kerf and having a width larger than the width of the kerf opening; and a connecting gap connecting the kerf opening and the flow channel. In the tread kerf, the kerf opening is formed to have a zigzag wave shape along the tire circumferential direction in a tread block, and the zigzag wave is formed such that the amplitude decreases downward along the depth direction of the block. According to the invention, the tread kerfs for a tire have a function of maintaining the block rigidity that may be deteriorated as a result of insertion of kerfs into tread blocks and also maintaining the block rigidity that may increase with the wear of the tire, at a certain level, and also have an effect of absorbing the water existing between the tire tread and the road surface when the tire runs on a wet road, thereby allowing the tire tread to be brought into direct contact with the road surface, and causing the absorbed water to be easily discharged through the lateral sides of the tread blocks.

A pneumatic tire includes circumferential main grooves extending in the tire circumferential direction on the tread surface, and in widthwise outermost land portions, widthwise grooves extending from the tread edges inward in the tire width direction and widthwise sipes extending from the tire widthwise inner edge of the widthwise grooves inward in the tire width direction and connecting to the circumferential main groove. Each widthwise sipe includes a widened portion, by the sipe bottom, with a larger sipe width than at the tread surface. A rectangle ratio is less than 0.8. In a tire radial region containing the widened portion, the widened portion includes a portion extending at a first angle relative to the tire width direction. In plan view of the tread surface, each widthwise sipe extends along the tire width direction or at a second angle smaller than the first angle relative to the tire width direction.

Tread for heavy-duty vehicle tire, having tread surface with at least one cavity forming a hidden channel which forms an additional groove after an amount of wear, each channel extended towards tread surface in the new state along its entire length by a sipe of small width, at least one channel having plurality of extensions from this channel towards tread surface to place the channel and the outside of the tread into communication from an amount of partial wear of the tread, each extension being a secondary channel having a first opening of elongate shape with a minimum dimension I0 and a maximum dimension Lo that opens onto tread surface and a second opening that opens into channel, wherein for at least one channel provided with extensions, each first opening of these extensions is formed by a side of the sipe that extends the channel.

In order to suppress an excessive increase in the temperature of a tread section, a tire includes: a first land portion that is formed to a tread section by providing plural circumferential direction grooves extending around a tire circumferential direction at a spacing in a tire width direction, and that includes plural first recesses provided around the tire circumferential direction of a wall face of the first land portion; and a second land portion that has a wider width than the first land portion, and that includes a greater number of second recesses than the number of the first recesses provided around the tire circumferential direction of a wall face of the second land portion.

The tire tread having a tread surface and a total thickness E and at least one main groove which opens when new onto a tread surface. In the vicinity of this main groove, at least one discontinuous secondary groove has a plurality of hidden parts and a plurality of open parts. The open parts are open onto the tread surface when new. The main groove and the discontinuous secondary groove have roughly identical main directions. The mean distance L1, which is a distance measured at the open parts between the mean surface of the main groove and the mean surface of the discontinuous groove, is less than the mean distance L2 measured between the mean surface of the main groove and the mean surface of the discontinuous groove in the regions of the discontinuous groove that do not have open parts.

A pneumatic vehicle tire for utility vehicles has a profiled tread having two circumferential ribs that are adjacent and are separated by a circumferential groove of depth H formed from radially inner and outer extension sections of height H.sub.1 and H.sub.2. The groove in the radially inner extension section is a channel of height H.sub.1 and breadth B.sub.1, and in the outer extension section is configured, along its circumferential extent, with an alternating sequence of first and second circumferential regions. The two flanks in the first regions are each configured, in the transition to the outer surface of the rib, with a chamfer of height H.sub.4 such that H.sub.4<H.sub.2, and are spaced by a distance B.sub.2 along their radial extent in the outer extension section from radially inward to radially outward as far as the chamfer.

Tire with radial carcass reinforcement having a tread of thickness E, this tread having a tread surface to come into contact with a roadway and comprising at least one cut opening onto the tread surface to form edge corners, this cut extending into the tread over a total depth H at most equal to the thickness E of the tread, this cut being, between the tread surface and a depth H1 at most equal to the total depth H, in the form of a sipe having a width D suitable for being able to close up at least in part under normal running conditions of the tire. There is also formed, in the vicinity, i.e. at a minimum distance from the said edge corner that is at most equal to five times the width D of the cut, of at least one edge corner of this cut and on the tread surface, at least one cavity having a depth h that is small in comparison with the depth of the cut, i.e. that is at most equal to 30% of the depth H, this at least one cavity reducing the compression rigidity of the tread in the vicinity of the said at least one edge corner.

Tire for a heavy goods vehicle, comprising a crown reinforcement, and, radially outside this crown reinforcement, a tread having a total thickness PMU of material intended to become worn during running, the crown reinforcement being formed by at least two working plies and a protection ply positioned radially outside the working plies and radially inside the tread, the narrowest working ply having a width in the range from 70% to 90% of the width W of the tread, the protection ply having a width at most equal to 70% of the width of the narrowest working ply, the tread comprising grooves only in the part radially outside the protection ply, each circumferentially orientated groove having a depth at least equal to 75% of the maximum thickness intended to become worn PMU. This tread comprises, axially between an axial end of the narrowest working ply and an axial end of the protection ply located on the same side of the equatorial plane, a channel that is generally circumferentially orientated and runs all the way around the tire, this channel being formed in such a way that the minimum distances between this channel and the working plies and between this channel and the protection ply are different from zero.

Particular embodiments of the present invention include a multi-stage tire tread having two or more wear layers comprising an outer wear layer and one or more inner wear layers arranged within the thickness of the tread below the outer wear layer and one or more outer grooves are arranged within the outer wear layer. The tread further includes a volumetric void ratio equal to approximately 0.25 to 0.40 in the unworn condition and approximately 0.25 to 0.40 in a worn condition where the outer, ground-engaging side is arranged along one of the inner wear layers in the worn condition, the tread further having a contact surface ratio equal to approximately 0.66-0.72 in the unworn condition and approximately 0.56-0.66 in the worn condition.

The invention provides for a heavy truck tire tread (2) having a longitudinal direction, a lateral direction and a thickness direction, said tread having a ground-engaging surface and comprising at least four longitudinal grooves, the at least four longitudinal grooves (3, 4, 5, 6, 7) comprising two open grooves (4, 6) and at least two partially hidden grooves (3, 5, 7), the partially hidden grooves comprising open portions and duct portions alternated along the longitudinal direction of the tread, said at least four longitudinal grooves defining two shoulder ribs, two intermediate ribs and at least one center rib, wherein the shape, size and position of the grooves are such that for any section of tread of any given section length L between 12 mm and 40 mm, the percentage difference in rubber mass of a rib section compared to a respective neighboring rib section of the same section length L in the same rib is less than a maximum percentage difference, wherein the maximum percentage difference for a shoulder rib is Ds(%)=50/L(mm), the maximum percentage difference for an intermediate rib is Di(%)=70/L(mm), and the maximum percentage difference for a full tread section is Da(%)=40/L(mm).