Abstract: At least one of land portion rows 14, 15, 16 that are formed in a tread surface portion 10a is constituted by a first land portion 17 and a second land portion 18 being alternately and consecutively arranged along the tire circumference direction R, and a first top surface portion 17a and a first inclined surface portion 17b whose recess amount inward in a radial direction of the tire gradually increases in accordance with heading from the first top surface portion 17a toward the outer side in a width direction of the tire H are provided in a first land portion 17, and a second top surface portion 18a and a second inclined surface portion 18b whose recess amount inward in the radial direction of the tire gradually increases in accordance with heading from the second top surface portion 18a toward the inner side in the width direction of the tire H are provided in a second land portion 18, and by the first inclined surface portion 17b and the second inclined surface portion 18b mutually overlapping in the circ

Abstract: A heavy-duty tire comprises two rows of middle blocks (11). The ground contacting face (S) of each middle block is defined as being surrounded with an axially inner longitudinal edge (14i), an axially outer longitudinal edge (14o), a first-side transverse edge (14a) and a second-side transverse edge (14b). The two transverse edges (14a and 14b) are substantially straight and substantially parallel with each other and inclined with respect to the tire axial direction. The axially inner longitudinal edge (14i) is nonlinear and has an axially inwardly protruding first-side protruding point (15a) and second-side protruding point (15b), and an axially outwardly denting part (16) therebetween. The axially outer longitudinal edge (14o) is nonlinear and has axially outwardly protruding first-side protruding point (20a) and second-side protruding point (20b), and an axially inwardly denting point (21) therebetween.

Abstract: A tread (1) having a plurality of raised elements (5) provided with at least one first incision (10) and at least one second incision (20). Each first incision (10) comprises at least two non-planar parts (111) separated by an intermediate part (112). The non-planar parts exhibit a dual undulation, whereas the planar parts have a single undulation. Each second incision (20) comprises at least two non-planar parts (211) separated by an intermediate part (212). The non-planar parts (212) exhibit at least one undulation (2112) in the depth of the tread of maximum amplitude C, whereas each intermediate part (212) of the at least one second incision (20) has no deformation in relief.

Abstract: Disclosed is a pneumatic tire including: plural blocks (7) formed by plural grooves (circumferential grooves 3 and lateral grooves 5) extending in a tire circumferential direction and in a tire width direction in a tread surface (1); sipes (9) narrower than the grooves, the sipes formed in each of the blocks (7); and plural projections (21) provided, in a middle region (M) in a depth direction of each sipe (9), on one sidewall surface (13) of the sipe (9), and having different projecting directions toward the other sidewall surface (15) of the sipe (9).

Abstract: To enhance cornering performance on each road surface and improve steering stability while ensuring traction performance and breaking performance of a pneumatic tire on a snow road or off-road. A shoulder land row (31) between a main groove (11) extending in the tire peripheral direction of a tread unit (2) and a tread end (TE) is partitioned into plan-view trapezoidal blocks (31B) with their widths reducing toward the outer side of a tire width direction by shoulder lug grooves (26) in an almost tire width direction. A plan-view trapezoidal notch (40) with its width reducing toward the inside of a block (31B) is formed in almost the center of the main groove (11) side edge of a block (31B), and an inclined surface (41) extending from the surface of the block (31B) toward the bottom of the main groove (11) is formed in the notch (40) integrally with the block (31B). This inclined surface (41) is formed stepwise by a plurality of recessed curved surfaces and protruding ridges formed between them.

Abstract: Provided is a pneumatic tire that has a directional tread pattern and includes: a rib-shaped first land area extending in the tire-circumferential direction in a center section of a tread portion; paired first main grooves being adjacent respectively to the two sides of the first land area; paired second land areas being adjacent respectively to the outer sides of the first main grooves; paired second main grooves being adjacent respectively to the outer sides of the second land areas; paired third land areas being adjacent respectively to the outer sides of the second main grooves; a fine groove extending at the center of the first land area; plural lug grooves formed in the first land area; and plural sipes formed in the first land area. The lug grooves alternate with the sipes along the tire-circumferential direction. Each lug groove intersects with a corresponding sipe.

Abstract: In a tire mold 10, in which a tread molding section 12 for molding of a tread comprises a plurality of segments 18 divided in a tire circumferential direction and the respective segments are provided movably in a tire radial direction, ridges 20 for molding of transverse grooves T2 on a tread surface are protrusively provided at least at circumferential ends 23 of the segment 18 in a posture (more specifically, a posture in parallel to a direction M of movement of the segment) inclined outward to a direction toward a center Om of the segment so as to be away from a circumferentially central portion 22 of the segment as it goes toward tip ends thereof.

Abstract: An object of the present invention is to provide a pneumatic tire having low rolling resistance and higher resistance against irregular wear. To achieve the above object, a pneumatic tire includes a tread portion comprising a plurality of block arrays each of which is constituted of a plurality of blocks that are partitioned by a plurality of main grooves extending in a circumferential direction of the tire and a plurality of lateral grooves crossing the main grooves, wherein at least one of the block arrays is provided with a thin rib that continuously extends in the circumferential direction of the tire in a central area of the block array as viewed in a width direction of the tire and is partitioned by two sipes extending in the circumferential direction of the tire, the depth of the sipes extending in the circumferential direction of the tire is 0.7 times or less of the depth of the lateral grooves.

Abstract: A pneumatic tire having shoulder blocks defined on a shoulder side of the tread surface by lateral grooves extending in the widthwise direction of the tire beyond a ground contact end of the tire, the shoulder blocks being arranged in the circumferential direction of the tire. A bottom-raising portion is provided only on a bottom of every other lateral groove of the lateral grooves. Two shoulder blocks adjacent in the circumferential direction of the tire are connected by the first bottom-raising portion.

Abstract: An object of the present invention is to provide a pneumatic tire capable of reducing the narrowing of the openings of sipes and increasing ground-contact performance by ensuring the edge effect and the water removal effect thereby increasing on-ice braking performance while providing a satisfactory durability to a sipe-forming blade mounted on the tire manufacturing die.

Abstract: There is provided a pneumatic tire having a shallow groove provided between zigzag sipes adjacent in the circumferential direction of the tire, a tire mold used for production of the pneumatic tire and a method of producing the pneumatic tire with the tire mold, which can reduce production cost of the mold, facilitate trimming operation and decrease waste from trimming while reduction of driving stability during turning on a wet road surface and occurrence of curing trouble are suppressed. The pneumatic tire of the present invention has a tread surface 1 where land portions 6, 8, 12, 13 and 14 are defined by grooves 2, 3, 4, 5, 7, 9 and 10. The land portions 6, 8, 12, 13 and 14 have tread surface sections 6a, 8a, 12a, 13a and 14a, in which a plurality of sipes 15 extending in a zigzag manner in the widthwise direction of the tire are arranged at prescribed intervals in the circumferential direction T of the tire.

Abstract: A pneumatic tire according to the present invention improves wet performance. The pneumatic tire has a tread surface 1. A first main groove 2 extending in the circumferential direction TC of the tire is provided in the tread surface 1. First lateral grooves 7 extending from the first main groove 2 outward in the widthwise direction of the tire beyond one ground contact end TX1 of the tire are disposed at prescribed intervals in the circumferential direction TC of the tire. Blocks 8 are defined by the first main groove 2 and the first lateral grooves 7. The first lateral grooves 7 comprise inner groove portions 7A and outer groove portions 7B. The inner groove portions 7A extend with their widths gradually increasing from the first main groove 2 outward in the widthwise direction of the tire to midways of the first lateral grooves 7.

Abstract: A tread 10 for a tire 2 has a plurality of tread elements or ribs 6, the shape of these tread ribs 6 is defined by a plurality of open grooves 12. The tread 10 has at least one full depth groove 12. The full depth groove 12 has a radially innermost groove bottom 14 providing a measuring location to establish the distance between the groove bottom 14 and outer surface of the tread 10 defining the tread depth. At least one tread rib 6 adjacent the at least one full depth groove 12 has one or more sipes 21, 22, 22A, or 24 extending radially inwardly from a radially outermost surface of the tread rib 6 inwardly to a depth greater than the distance X. The distance X defines a fully worn tread depth level extending radially above the full depth groove bottom 14. Preferably the location X is defined by a tread wear indicator (TWI) molded into the tread indicating the location of the distance X relative to the groove bottom 14 which defines the fully worn tread depth.

Abstract: A heavy duty tire (1) comprising at least three rib-like land portions (7) with a block row where blocks (6) defined by circumferential main grooves (3) extending in the circumferential direction and lateral grooves (5) are arranged in the circumferential direction, wherein the lateral grooves (5) are provided, in their bottoms (S), with a sipe-forming region (Sy) having a sipe (20) which extends along the groove center line and has a width of 0.5 to 2.0 mm, and wherein the depth (DY) in the sipe-forming region (Sy) of the lateral grooves (5) is from 0.5 to 0.75 times the depth (H) of the circumferential main grooves (3), and the depth (DS) of the sipe (20) is from 0.75 to 1.0 times the depth (H) of the circumferential main grooves.

Abstract: The tire has a ground contacting tread portion, the tread comprising at least one straight circumferentially extending groove. The groove defines one lateral side and a lateral boundary of a plurality of tread elements. At least one tread element has a chamfer within the tread element and inward of the lateral boundary of the tread element. The chamfer extends in the circumferential direction of the tire and has an inclined radially outer surface. The chamfer has at least one traction element in the radially outer surface, the indentation extending radially inward of the radially outer surface of the chamfer.

Abstract: A plurality of shallow grooves which are shallower than a sipe are formed on land sections formed on treads of a pneumatic tire. The shallow grooves are configured so that a total sectional area of the shallow grooves per unit area in a cross section in a tire width direction in at least one of tread end areas arranged at end sides of the tread surface in the tire width direction or land end areas arranged at portions adjacent to a drain main groove on the land sections becomes larger than a total sectional area of the shallow grooves per unit on the other areas.

Abstract: An off-road tire (1) comprises a tread portion (2) provided with blocks (10, 11) forming a sea area (8) therearound. The sea area (8) is provided in the bottom (14) thereof with recesses (13), wherein the recesses (13) are arranged circumferentially of the tire and each extend axially of the tire, and the depth (d) of each of the recesses (13) is gradually increased towards its center (13a), whereby the enveloping power is improved.

Abstract: The present invention has an object to improve snow/ice performance, wet performance, and wear resistance of a pneumatic tire. The present invention provides a pneumatic tire which includes, in a tread, at least two circumferential grooves extending along a tire circumferential direction, a plurality of lug grooves extending in a direction crossing the circumferential grooves, and a plurality of blocks (30, 32) sectioned by the circumferential grooves and the lug grooves, wherein each of the blocks (30, 32) has a circumferential sipe (40, 46) connecting the lug grooves to each other formed on both sides of the circumferential sipe in the tire circumferential direction, and two lateral sipes (42, 48) extending from the circumferential sipe (40, 46) to a block end in a tire width direction, and the circumferential sipe (40, 46) extends so as to change the direction thereof at least once.

Abstract: A pneumatic tire provided with a tread pattern on which a plurality of blocks are formed with three circumferential grooves which extend along a circumferential direction of the tire and lateral grooves which traverse the circumferential grooves, wherein the lateral groove disposed between the circumferential grooves has a depth that is from 40 to 70% of a depth of the circumferential groove, a groove bottom sipe with both open ends is formed on a groove bottom of the lateral groove, and a land portion sipe, whose length in the circumferential direction of the tire is longer than that in a width direction of the tire, is formed on the block.

Abstract: A pneumatic tire provided with a tread pattern on which a plurality of blocks are formed with circumferential grooves which extend along a circumferential direction of the tire and lateral grooves which traverse the circumferential grooves, wherein the lateral groove disposed between the blocks on the endmost tread edge region has a depth from 10 to 50% of a depth of the circumferential groove to be traversed and has a groove bottom concave portion whose both ends in a longitudinal direction are disposed inside the groove bottom, and a width of the groove bottom concave portion, which is determined on the basis of the bottom plane of the groove bottom, is from 25 to 45% of a groove width of the lateral groove.

Abstract: In a pneumatic tire in which a tread with a plurality of grooves 1 and 2 including main grooves 1 extending in the tire circumferential direction formed and in which block 3 is formed on shoulder portions of tread T by grooves 1 and 2, on intersection line L between a surface of tread T and a surface of side portion S, the first sipes 11 extending in the tire circumferential direction R are formed, and the depth direction of the sipes 11 and 12 is parallel to tire equatorial plane C, and the sipes 12 are deeper than the sipes 11 and the sipes 12 are wider than the sipes 11, and height difference between a surface of wearing region 13 and a surface of side portion S is not greater than 2.0 mm.

Abstract: A pneumatic tire for use on iced and snowed road surfaces has a tread surface. The tread surface has a plurality of main grooves extending in a circumferential direction of the tire and a plurality of lateral grooves extending in a width direction of the tire. Blocks are defined by the main grooves and the lateral grooves. The blocks have a ground contact face which has a plurality of pairs of sipes comprising a left sipe and a right sipe extending in the tire width direction. The plurality of pairs of sipes are placed in a predetermined interval in the tire circumferential direction. Each of the left and right sipes of each pair extends from a width-directional center portion of the ground contact face of the block toward each way of the tire width direction so as to open its outer end to each side face of the block.

Abstract: A tire for a vehicle wheel includes a carcass structure, a belt structure, and a tread band. The tread band pattern includes a central zone and two axially-opposite shoulder zones. The central zone is delimited between axially-inner circumferential grooves and includes at least two intermediate circumferential grooves and a plurality of first transverse recesses inclined relative to a circumferential direction of the tire. The first transverse recesses are connected to at least one of the intermediate circumferential grooves. The shoulder zones are each delimited between axially-inner and axially-outer circumferential grooves. The shoulder zones include a plurality of second transverse recesses inclined relative to the circumferential direction. The at least one of the intermediate circumferential grooves includes a substantially V-shaped cross-section.

Abstract: A vehicle having a profiled tread, having tread blocks (1) in at least some regions of its circumference, characterized in that for at least some of the tread blocks (1) at least the tread block edges (2) running into the tire contact patch (11) and extending at an angle to the central plane of the tire are lowered over their entire length with respect to the central plateau (3) of the respective tread block (1).

Abstract: A tyre includes a tread including a relief pattern delimited by a plurality of circumferential and transverse grooves forming at least one circumferential row of blocks projecting from a base surface of the tread and extending radially outward as far as top surfaces of the blocks. Each block is delimited by longitudinal and transverse lateral surfaces. Each lateral surface is part of at least one wall of the grooves. At least one block includes at least one notch in one or more of its surfaces. At least one side of the at least one notch is open along an entire length of one of the surfaces. The at least one notch includes a greater dimension oriented in a direction of one of the grooves and is tapered along that dimension between a base and a vertex opposite the base. A method for increasing traction of the tyre is also disclosed.

Abstract: Tire tread including a pattern formed by at two ridges of mean width L, which include a plurality of incisions whose traces on the contact surface extend between two points of intersection A and B, the segment AB making an angle with the transverse direction of the tread at most equal to 40°, the tread wherein each incision, of mean width E, includes a succession of incision portions, some of said incision portions having, on any surface parallel to the contact surface in the new condition and located between said surface in the new condition and ⅔ of the maximum depth of the incision, traces that make an average angle &bgr; at most equal to 15° with the longitudinal direction of the tread, said portions having a total length Lt which is at least equal to one-fifth of the ridge width; and in that the incision portions whose traces make an average angle &bgr; are provided on their opposite walls with relief elements of amplitude K designed to cooperate with one another to block relative movement

Abstract: The invention is to improve wear resistance and resistance to crack growth of an off-the-road tire having a gauge of a tread rubber of 60-200 mm, in which a plurality of widthwise grooves extending substantially in a widthwise direction of the tire are arranged in each side region of the tread, and a pair of circumferential fine grooves continuously extending straight-forward or zigzag in a circumferential direction of the tire are arranged in a central zone of the tread, and a plurality of widthwise fine grooves extending substantially in the widthwise direction of the tire and contacting their grooves walls with each other in a ground contact area are arranged between these circumferential fine grooves.

Abstract: A tread of elastomeric material for tires, this tread being provided with a plurality of incisions, each incision of average width e being defined by facing walls, this tread being characterized in that at least one of the walls defining each incision comprises at least one first series and one second series of lines of motifs forming reliefs relative to said wall and having a maximum height measured perpendicular to said wall at least equal to {fraction (1/10)} of the width e, each series of lines comprising a plurality of lines extending in the same direction, the lines of the first series intersecting the lines of the second series, and in that at least one of the walls is provided over its entire surface with an average roughness of between {fraction (1/100)} and {fraction (1/10)} of the width e of the incision.

Abstract: A heavy duty radial tire which is provided with traverse grooves extending between the tread edges and longitudinal grooves extending between the traverse grooves so as to form shoulder blocks arranged along each of the tread edges and inner blocks each disposed on the axially inside of one of the shoulder blocks. The longitudinal grooves between the shoulder blocks and the inner blocks have a depth Wga of 0.7 to 1.0 times the depth Dy of the traverse grooves, and the longitudinal grooves are each inclined at an acute angle with respect to the circumferential direction to have an axial extent range Y whose axial width W1 is in a range of from 1.0 to 10.0 times the depth Wga. In a cross section of the tire under a normally inflated unloaded condition, the tread profile is made up of a center profile Si and a shoulder profile So. The shoulder profile So extends continuously from each of the axial ends of the center profile Si through an inflection point P to one of the tread edges.

Abstract: A tread (1) provided with a plurality of cutouts (5, 6, 71, 72, 73, 81, 82, 83) of essentially transverse orientation and characterized in that:

Abstract: A tire tread having grooves of transverse general orientation defining a plurality of blocks arranged so as to form a tread pattern having a preferred direction of travel, the blocks having a contact face, two lateral faces, a leading face forming an angle a greater than 90° with the contact face and a trailing face. For at least one tread pattern block, the trailing face of the block is formed of an upper part extending from the running face of the block which is extended towards the inside of the tread by a lower part. Furthermore, the upper part of the trailing face is undercut and forms an angle &bgr; of less than 90° with the contact face, whereas the lower part, which is inclined so as to form an angle &dgr; greater than 90° with the contact face, is provided with at least one recess which extends into the interior of the block.

Abstract: A tyre for a vehicle wheel includes a carcass structure, a belt structure, and a tread band. The tread band pattern includes a central zone and two axially-opposite shoulder zones. The central zone is delimited between axially-inner circumferential grooves and includes at least two intermediate circumferential grooves and a plurality of first transverse recesses inclined relative to a circumferential direction of the tyre. The first transverse recesses are connected to at least one of the intermediate circumferential grooves. The shoulder zones are each delimited between axially-inner and axially-outer circumferential grooves. The shoulder zones include a plurality of second transverse recesses inclined relative to the circumferential direction. The at least one of the intermediate circumferential grooves includes a substantially V-shaped cross-section.

Abstract: The present invention relates to a radial ply tire (230) with a tread (232) subdivided transversely into a central portion (250) having central ribs (260a,260b), shoulder portions (254a, 254b) having shoulder ribs (270a,270b) and intermediate portions (252a, 252b) having intermediate ribs between the central portion and the shoulder portions. The tread has intermediate grooves (262a,262b) between the central ribs and the intermediate ribs (266a,266b) and shoulder decoupling grooves (264a,264b) between the intermediate ribs and the shoulder ribs (270a,270b). The shoulder decoupling grooves having a depth (D1) being less than the intermediate decoupling grooves whereby the footprint width of the tread surface can expand from first width (NLFPW) under normal load to a second width (HLFPW) under heavy load.

Abstract: An assembly for manufacturing vehicle tires with light-reflective members has one or more plug inserts positionable inside a tire mold before vulcanization of the tire. The plug inserts each have a cutout in the back thereof corresponding to the portion of the tread design where reflective members are to be positioned. An elongated reflective member is placed in each of the plug inserts. When a vehicle tire is placed in the tire mold and treated under pressure, the tire expands conforming to the tire mold, while fusing the light reflective member into the tire body.

Abstract: A tread for a tire for a vehicle of high loading capacity which travels on bumpy roadways, having a tread pattern comprising elements in relief formed by at least one first and one second cutout (1, 2) which are oriented differently. The first cutout (1) opens into the second cutout (2) without crossing it to form a T-shaped connecting region. The tread pattern according to the invention is characterized in that one of the walls (22) of the second cutout (2) is provided, in the connecting region, with a protrusion (6) which extends substantially in the direction of the first cutout (1), this protrusion (6) having, on a surface parallel to the running surface, a contour C, the point of which which is farthest from the second wall is at a distance at least equal to 50% of the width L2 of the second cutout (2). This protrusion reduces the maximum diameter of a spherical object which may be introduced into said connecting region.

Abstract: A radial ply pneumatic tire 10 for trucks or trailers has a tread 12 with at least three circumferential grooves 20,22 extending circumferentially to divide the tread 12 into at least four parts and lateral grooves 30,31,32,33,34 extending across the at least four parts of the tread to form at least four rows 1,2,3,4 and 5 of circumferentially separated blocks 40. The circumferential grooves 20,22 have average groove widths of W1 for a depth between the radially outer surface of the adjacent blocks and a groove depth that is less than 60% of the non-skid depth D, the circumferential grooves having a second average groove width W2 at the groove depth less than 60% of the non-skid depth D, the second average groove width W2 being less than 50% of W1. The lateral grooves 30,34 in each shoulder row 15 have a first average groove width W3 and a groove depth that is less than 60% of the non-skid depth D.

Abstract: The present invention is directed to A plurality of vehicle tires having tread patterns of substantially the same outer appearance, wherein the tread patterns comprise a primary tread pattern comprising blocks and/or ribs separated by broad cut-outs and a secondary tread pattern on the blocks and/or ribs of the primary tread pattern comprising fine cuts. At least one vehicle tire has fine cuts of low depth and at least one different tire has sections of the fine cuts that have a different depth of fine cuts. The at least one vehicle tire has different driving characteristic from the at least one different vehicle tire. The advantage of the vehicle tires of the present invention is that a performance characteristic of the tire can be chosen by altering the structure of specific sections of the tire, without varying the fundamental opial appearance of the tire.

Abstract: A pneumatic tire having improved snow traction and tread wear, and improved noise and handling properties, has 80 to 105 pitches and a sipe density of 1.0 to 1.1. The tire has a substantially square footprint, and has a footprint shape factor (FSF) of 1.0 to 1.25. The tire has an open central and intermediate region, as compared to the shoulder region, and has lateral groove depths that vary from 50% to 100% of the tread depth, wherein the shallower grooves are disposed toward the central and intermediate regions of the tire.

Abstract: A pneumatic tire having improved snow traction and treadwear, and improved noise and handling properties, has 80 to 105 pitches and a sipe density of 1.0 to 1.1. The tire has a square footprint, and has a footprint shape factor (FSF) of 1.0 to 1.25. The tire has an open central and intermediate region, as compared to the shoulder region, and has lateral groove depths that vary from 50% to 100% of the tread depth; wherein the shallower grooves are disposed toward the central and intermediate regions of the tire.

Abstract: A pneumatic tire having improved snow traction and tread wear, and improved noise and handling properties, has 80 to 105 pitches and a sipe density of 1.0 to 1.1. The tire has a substantially rounded footprint, and has a footprint shape factor (FSF) of 1.2 to 1.5. The tire has an open central and intermediate region, as compared to the shoulder region, and has lateral groove depths that vary from 50% to 100% of the tread depth, wherein the shallower grooves are disposed toward the central and intermediate regions of the tire.

Abstract: A tire for vehicle wheels includes a tread band having a tread pattern defined between two shoulder ends of the tire. The tread pattern includes two lateral rows of grooves and at least one third row of grooves arranged between the lateral rows. All of the grooves are separate from one another so as to produce a pattern with no intercommunicating paths between the grooves. End portions of the grooves of the at least one third row extend outside a footprint of the tire. A dimension of each of the grooves of the at least one third row relative to a length of the tire footprint causes water drainage from underneath the tire footprint. A tire including the ability for acoustically signalling low air pressure, a method for checking tire air pressure using an acoustic signal, and an acoustic signalling device for vehicle wheels are also disclosed.

Abstract: A heavy duty tire is provided in the tread portion with a circumferentially extending main groove on each side of the tire equator, a circumferentially extending narrow groove on each side of each main groove, lug grooves extending from the tread edges to the axially inner narrow grooves, and slits extending between the inner narrow grooves so as to form a rib-like portion between the two inner narrow grooves, first blocks between the inner narrow groove and main groove, second blocks between the main groove and axially outer narrow groove, and third blocks between the outer narrow groove and tread edge; the main grooves are disposed at a distance of 15 to 25% of the tread width from the tire equator; the main groove depth is 10 to 12% of the tread width; the narrow groove depth is less than the main groove depth; and the slit depth is 0.2 to 0.3 time the main groove depth.

Abstract: A tire tread band for medium/heavy duty motor-vehicles having circumferential grooves confining three pairs of respectively center, intermediate and shoulder ribs. Respective tread blocks are defined along the center and intermediate ribs and they are confined by transverse cuts. The center cuts impart a cusp-shaped end conformation and a hollow-shaped end conformation to the respective blocks, and the shapes of said end portions mutually match. The intermediate cuts run in the linear extension of the center cuts to give the respective blocks a rhomboidal configuration. The tire can be alternately associated with a driving axle or a driven axle, by merely reversing its direction of rotation, so that the following results are selectively achieved: an increase in the traction capability by the intermediate blocks or an increase in the directional capability as a result of the mutual wedging between the center blocks at the ground-contacting area.