The tread has a contact face that is provided with at least one circumferential groove and a transverse grooves opening to the contact face and delimiting contact elements. The tread has a center region and shoulder regions and is provided with at least one compressive contact element among the contact elements. A volumetric void ratio of the compressive contact element in a unit region surrounded by a center of the at least one circumferential groove and a center of the transverse grooves delimiting the compressive contact element is at least equal to 25%. An aspect ratio, which is defined as a ratio of a surface of the compressive contact element supposed to contact with ground divided by a sum of a surface area of the compressive contact element touching with air other than the surface of the compressive contact element supposed to contact with ground, is at most 70%.

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 width W3 of the auxiliary groove of the resonator is 80% or less of the groove depth D1 of the first circumferential main groove.

Tire (1) for a heavy-duty vehicle of civil engineering type, and more particularly to the tread (2) thereof, and seeks to improve the grip thereof, while at the same time ensuring a satisfactory compromise with wearing and thermal endurance. The tread (2) comprises cuts (3, 4, 5) distributed, in a circumferential direction (XX′) of the tire, among circumferential grooves (3) and, in an axial direction (YY′) of the tire, transverse sipes (4) and transverse grooves (5), the cuts (3, 4, 5) delimiting elements in relief (6), each cut (3, 4, 5) being delimited by two faces facing one another and each face intersecting the tread surface (21) along an edge corner (311, 321; 411, 421; 511, 521). The tread (2) having a longitudinal edge corners ratio TA.sub.X equal to the ratio L.sub.X/S between the sum L.sub.X of the projections, on to the circumferential direction (XX′), of the effective edge corner lengths, contained in an elementary tread surface portion of surface area S, and the surface area S, and a transverse edge corners ratio TA.sub.Y equal to the ratio L.sub.Y/S between the sum L.sub.Y of the projections, onto the axial direction (YY′), of the effective edge corner lengths, contained in an elementary tread surface portion of surface area S, and the surface area S, the longitudinal edge corners ratio TA.sub.X is at least equal to 4 m.sup.−1 and the transverse edge corners ratio TA.sub.Y is at least equal to 6 m.sup.−1.

A tyre comprises a tread portion comprising a shoulder main groove and a shoulder land region. The shoulder land region includes an outer region, a middle region, and an inner region. The shoulder land region is provided with a plurality of shoulder sipes having components in a tyre axial direction. A sipe ratio of the middle region is smaller than the sipe ratio of the outer region and the sipe ratio of the inner region.

A tire comprises a directional tread of width (W), having a total volume VT, comprising voids (221, 211, 212) defining a voids volume VE. There is defined a volumetric voids ratio TEV=VE/VT, part of the voids (211) delimits blocks (21A, 21B) which are organized into patterns (26) of blocks of pitch P succeeding one another in the circumferential direction (X). Part of the voids forms sipes (211, 212) in one of the patterns. The sipes density SD corresponds to the ratio of a sum of the projected lengths (lpyi) of the sipes in an axial direction to the product of the pitch P of the pattern times the width (W), all multiplied by 1000. SD in any pattern of pitch P is comprised between 10 mm.sup.−1 and 70 mm.sup.−1. TEV is at least equal to 0.29 and at most equal to 0.35.

A tire comprises a directional tread which forms a contact patch AC during running. The tread comprises a plurality of blocks (21A, 21B) which form a contact surface SC. The surface voids ratio is defined by TES=(AC−SC)/AC. The blocks (21A, 21B) are organized into patterns (26) of blocks of pitch P which succeed one another in the circumferential direction (X), in a pattern comprising at least one sipe. The sipes density is defined by the formula

[00001]$\mathrm{SD}=\frac{{.Math.}_{i=1}^n\mathrm{lpyi}}{P*W}*1000,$

where n is the number of sipes, lpyi is the projected distance of the sipe i in the axial direction (Y), and W is the width of the tread. Simultaneously, SD is at least equal to 10 mm-1 and at most equal to 70 mm-1, and TES is at least equal to 0.40 and at most equal to 0.70.

A tire comprises a tread of width (W), having a total volume VT, comprising voids (221, 211, 212) defining a voids volume VE. There is defined TEV=VE/VT. Voids (211) delimit blocks (21A, 21B) organized into patterns (26) of pitch P succeeding one another in the circumferential direction (X). Part of the voids forms sipes (211, 212) in one of the patterns. SD corresponds to the ratio of a sum of the projected lengths (lpyi) of the sipes in an axial direction (Y) to the product P times W, multiplied by 1000. The tread forms a contact patch AC and blocks (21A, 21B) form a contact surface SC: TES=(AC−SC)/AC. For the tread when new, SD in any pattern of pitch P is comprised between 10 mm.sup.−1 and 70 mm.sup.−1, and TES/TEV is comprised between 1.5 and 1.9.

In the pneumatic tire, the ratio TW/SW of the ground contact width TW of the tire and the maximum width SW of the tire is 0.75 to 0.95. The tire width direction outside end of the belt layer extends in the tire circumferential direction and is positioned outside in the tire width direction than the circumferential direction groove formed most outside in the tire width direction. A width direction sipe extending in the tire width direction and closest to the tire circumferential direction end portion of the block and a width direction sipe adjacent to the width direction sipe and extending in the tire width direction are formed in the block, and a distance from the tire circumferential direction end portion to the width direction sipe along the tire circumferential direction is longer than a distance from the width direction sipe to the width direction sipe along the tire circumferential direction.

A tire includes a tread portion including first and second tread edges, three or more circumferential grooves, and four or more land portions. The circumferential grooves include a first shoulder circumferential groove nearest to the first tread edge. Each land portion is provided with only sipes and is not provided with lateral grooves. The land portions include a first shoulder land portion having the first tread edge, and a first middle land portion adjacent to the first shoulder land portion. The first middle land portion is provided with first middle sipes traversing the first middle land portion completely in the tire axial direction. The first shoulder land portion is provided with first shoulder sipes extending from the first shoulder circumferential groove to the first tread edge. The first shoulder sipes have a circumferential pitch length smaller than a circumferential pitch length of the first middle sipes.

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.