Abstract: A vehicle comprises Anti Lock Brake System (ABS) and front tires and rear tires which are capable of displaying maximum braking effect when the ABS is in operation, each of the tires comprises a plurality of tread elements divided by tread grooves, and the tread pattern rigidity Pr of the rear tire is more than the tread pattern rigidity Pf of the front tire, wherein the tread pattern rigidity P (Pr, Pf) is defined as a quotient of the total of circumferential rigidity of all the tread elements existing in a ground contacting region of the tire which is divided by the area of the ground contacting region, and the circumferential rigidity K of each tread element is defined as a quotient of a tangential force F in kgf received at the ground contacting region which is divided by a displacement y in mm at the ground contacting region.

Abstract: A pneumatic tire includes a tread pattern having circumferential and lateral grooves forming a plurality of circumferentially extending ribs, each rib having a plurality of tread blocks. A plurality of tie bars extend circumferentially across certain of the lateral grooves between adjacent tread blocks in at least two of the ribs which are located equally opposite of a mid-circumferential plane of the tire. The tie bars have a pair of sidewalls and a sloped top surface with the slope of the top surface in one of the ribs being opposite to the slope of the tie bars in the other rib to generate a residual aligning torque (RAT) on the tire.

Abstract: An angle, which is formed by a tire leading edge side contour line of a ground-contact configuration and a side surface of a leading edge side of a block of a first block row disposed along a tire circumferential direction, and an angle, which is formed by the tire leading edge side contour line of the ground-contact configuration and a side surface of a leading edge side of a block of a second block row disposed parallel to and asymmetrically to the first block row, are set to be substantially equal. In this way, levels of pitch noises of the first block row and the second block row can be made equal. By adjusting tire circumferential direction phases of blocks of the first block row and the second block row, the pitch noises of the same level interfere with one another. A reduction in pattern noise is thereby achieved without changing a negative ratio.

Abstract: A vehicle tire is provided in the tread portion with sipes capable of improving the rigidity of tread rubber, wherein each of the sipes comprises an radially outer part and radially inner parts, the radially outer part extends radially inwards from the tread face to a certain depth H and extends continuously in the longitudinal direction thereof, the radially inner parts extend radially inwards from the radially inner end of the radially outer part, the radially inner parts comprises at least one first inner part inclined towards one side of the radially outer part and at least two second inner parts inclined towards the other side of the radially outer part, and the first and second inner parts alternate with each other in the longitudinal direction of the sipe.

Abstract: A pneumatic tire in which a block formed in a tread surface has, in a ground contacting surface thereof, a closed sipe which is formed so as to not open onto a groove. The sipe has a first opening formed in the ground-contacting surface of the block, a second opening formed at side surfaces of the block, and a hole which communicates the first opening and the second opening. In accordance with this structure, water taken-in into the sipe from the first opening at the ground-contacting surface of the block is discharged to the second opening contacting at the side surface facing to the groove. As a result, water drainability of the sipe is improved without lowering rigidity of the block. Thus, a ground contacting performance of the block improves. The pneumatic tire therefore has improved performance on wet roads and improved performance on snowy and icy roads without the rigidity of blocks decreasing.

Abstract: A pneumatic tire includes a tread having a plurality of spaced tread blocks separated by grooves or slots. A plurality of tie bars extend across the grooves or slots between adjacent tread blocks. The tie bars have a pair of sidewalls and a top surface with an undercut formed in at least one of the sidewalls to reduce tie bar stiffness and provide increased water evacuation as the tread wears. The top surface of the tie bar is lower than the top surfaces of the adjacent tread block and the undercut can be formed in only one or both sidewalls of the tie bar and have various stepped and tapered configurations.

Abstract: A vehicle tire comprises a central tread portion divided into central blocks B0 by central oblique grooves (g); a lateral tread portion divided into four kinds of blocks B1, B2, B3 and B4 by first and second oblique grooves (ga and gb) extending from a circumferential groove (G) to a tread edge, and cross oblique grooves (gc) extending between the first oblique grooves (ga1) while crossing the second oblique groove (gb); the central oblique grooves (g) and the cross oblique grooves (gc) inclined reversely to the first and second oblique grooves (ga and gb); the number of each of the first to fourth lateral blocks B1 to B4 in each of the lateral land portions being equal to the number of the central blocks B0; and each of the first oblique grooves (ga) and two of the cross oblique grooves (gc) meeting with at axially different positions (P1 and P2).

Abstract: As shown in FIGS. 1 and 2, in a pneumatic tire of the present invention, block-shaped land portions 18 are divided by main grooves 14 and lug grooves 16 on the tread 12 of a studless tire 10 and a plurality of transverse sipings 20 is formed on each of the block-shaped land portions 18. Each sipings 20 is formed from a first linear portion 20A, a second linear portion 20B, and a sloping line portion 20C. The first linear portion 20A essentially extends in a direction perpendicular to the surface 18A of the block-shaped land portion 18 and contacts the surface 18A, the second linear portion 20B essentially extends in a direction perpendicular to the surface 18A and is separated from the surface 18A, and the sloping line portion 20C inclines to connect the ends of the first linear portion 20A and the second linear portion 20B. In each of the sipings 20, the position D1 of the sloping line portion 20C is set to 10% to 60% of the siping depth D.

Abstract: A tread pattern having at least one circumferential groove and transverse grooves extending from the circumferential groove defining tread blocks there between. The tread blocks include sidewalls limiting the longitudinal groove laterally and projections projecting from the sidewalls into the circumferential groove. The width of each of the projections is less than 10% the circumferential dimension of the respective tread block. To convert a mold having elements that produce tread blocks with substantially flat sidewalls into a mold that produces the tread pattern, channels are machines into the sidewalls of the mold elements.

Abstract: A pneumatic radial tire, wherein five main grooves extending in the circumferential direction of a tire are provided on a tread to divide into and form land portions of six rows, each land portion is divided into block rows constituted by a plurality of blocks by means of a plurality of subgrooves extending in the direction of width of the tire, and an area ratio of the blocks is set at a relationship of 1:0.9 to 1.1:1.8 to 2.2 from the block row of the shoulder side to the block row of the center side, in a region between ends of a belt layer having a maximum width embedded in said tread.

Abstract: A pneumatic tire comprises a tread portion provided with blocks, each block provided with circumferentially opening V-shaped corners each defined between two corner walls intersecting each other. In a cross section including the intersecting line K of the two corner walls and a normal line drawn normally to the tread face from a radially outer end of the intersecting line K, the intersecting line K comprising an upper slanting part KU and a lower normal part KL, the upper slanting part KU extending radially inwards from the tread face to a point P1 with an inclination angle &thgr;1 with respect to said normal line, and the lower normal part KL extending radially inwardly from the point P1 in substantially parallel to the normal line. The depth D1 of the point P1 from the tread face being in a range of from 0.30 to 0.50 times the height H0 of the block.

Abstract: Sipes extending from one end of a block to the central area of the block and sipes extending from the other end of the block to the central area of the block (sipes 24, 28, 32 and 36) are inclined in directions opposite to each other. The sipes extending from one end of the block and the sipes extending from the other end of the block intersect a common line extending along the circumferential direction of the tire. Due to this structure, the number of portions of the sipes, which portions are located in the central area of the block, is made greater than that in the peripheral area of the block. The density of sipes is thus increased in the central area of a block where water tends to form when driving on ice, for improving braking and traction properties on ice.

Abstract: The present invention relates to a traction winter tire with rows (A-F) of tread pattern blocks (11) and circumferential (a-e) grooves and transverse grooves (j-o) separating pattern blocks from each other, the tread pattern blocks comprising sipes (7, 8a, 8b, 9a, 9b) opening to the tread surface and extending into the tire for enhancing the grip of the tread with a road surface, said sipes being discontinued at support areas (13) operable to attach anti-skid studs (12). The winter tire is characterized in that the tread pattern blocks are displaced relative to one another such that overlapping and axially adjacent tread pattern blocks are connected in pairs into double tread pattern blocks (2) by a bridge part (3), and tread pattern blocks in the shoulder area of the tire are, alternatingly, a tread block of a double tread block and an unbound single tread block (11).

Abstract: An on/off-road tread (40) for passenger or light truck tire (10) has an off-road tread (40) including a central on road tread (100). The tread (40) extends from at or above a radial location of the maximum section width SW of the tire (10) but less than a radial location of 65% of the section height SH of the tire (10).

Abstract: When a single performance or a plurality of antinomical performances are to be achieved, the best mode of a tire is designed under a given constraint condition. Each of blocks included in two pitch groups designated in a pitch array is modeled (100), an objective function representing a tire performance evaluation physical amount, a constraint condition for restricting a tire shape, and a design variable which is an angle of a wall surface determining each of block shapes are determined (102). Next, the design variable is varied continuously by &Dgr;ri to determine a modified model (104 to 108). A value of the objective function of the modified model and a value of the constraint condition are calculated, and a sensitivity of the objective function and a sensitivity of the constraint condition are determined (110, 112).

Abstract: In a pneumatic radial tire having blocks 4 formed on its tread 1 by transverse grooves 3 extending along its width and main grooves 2 extending circumferentially across the transverse grooves 3, every two blocks 41C and 41M spaced apart from each other transversely by one of the main grooves 2 have a sipe 81CM which extends transversely from one block 41C to the other 41M across the main groove 2 and is open in the tread surfaces and the said main groove throughout its length. The sipe 81CM has along its length and depth a cross section 810 defined by an inner portion 810a and 810b made in each block 41C or 41M, a substantially U-shaped portion 810c made in the bottom and side walls 21, 22 and 23 of the main groove 2, and a portion 810d or 810e made in each block for connecting the inner and substantially U-shaped portions 810a and 810b, the connecting portion having a depth reduced by a shelf 9a or 9b formed on each block.

Abstract: A tyre includes a tread band having at least two substantially parallel longitudinal grooves and at least one series of transverse grooves crossing the longitudinal grooves. The transverse and longitudinal grooves delimit at least two rows of shoulder blocks and at least one row of centre blocks. The transverse grooves have at least two transverse channels, each including an outer end stretch in an orientation substantially perpendicular to an equatorial plane of the tyre and a curvilinear connecting stretch close to the equatorial plane. The joining of laterally-opposite transverse channels gives each transverse groove a continuous course. At least one transverse channel of at least one of the transverse grooves also includes an inner end stretch. The connecting stretch interconnects the outer end stretch with the inner end stretch in a continuity relationship.

Abstract: A method for directional force correction of pneumatic tires that simultaneously corrects radial and tangential force exerted by the tire. The method allows for the correction of tangential force regardless of the rotational direction of the tire. This invention accomplishes this end through an improved force correction technique, wherein at least two rotary grinders are employed. In the inventive method, the rotational direction of one grinder is reversed in relation to the rotational direction of the other grinder(s). Therefore, at least one grinder will engage the tire in an “up-grinding” manner, and at least one grinder will engage the tire in a “down-grinding” manner. The result is that across the width of the tire's tread surface, some tread blocks will have a “heel-to-toe” appearance, while others will appear “toe-to-heel.

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: A pneumatic tire comprises a tread portion provided with a longitudinal main groove extending continuously in the tire circumferential direction and axial grooves each having at least one opening into the longitudinal main groove, and at least one of two groove walls of each of the axial grooves swells gradually towards the opening. The axial grooves include a groove having two openings and/or a groove having one opening and one closed end. The swelling part of the groove wall can be formed by a convexly curved surface extending from the tread surface towards the groove bottom, and having a single radius of curvature gradually decreasing towards the opening.

Abstract: A non-directional farm tire 10 has a tread 32. The tread 32 has a set 60 having three lugs 50A, 50B, 50C. The lugs 50A and 50B have substantially parallel lug centerlines 63 while the lugs 50C have centerlines 63 generally perpendicular to the centerline 63 of lugs 50A and 50B. The set 60 is repeated a plurality of times circumferentially about the tread 32. The set 60 extends along a line 62 through the lug centers 61 in a substantially straight line across the tread 32 from the first tread edge 33A to the second tread edge 33B. The centerlines 63 of each of the shoulder lugs are parallel and form an acute angle &thgr; with the equatorial plane of about 45°.

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 method for directional force correction of pneumatic tires that simultaneously corrects radial and tangential force exerted by the tire. The method allows for the correction of tangential force regardless of the rotational direction of the tire. This invention accomplishes this end through an improved force correction technique, wherein at least two rotary grinders are employed. In the inventive method, the rotational direction of one grinder is reversed in relation to the rotational direction of the other grinder(s). Therefore, at least one grinder will engage the tire in an “up-grinding” manner, and at least one grinder will engage the tire in a “down-grinding” manner. The result is that across the width of the tire's tread surface, some tread blocks will have a “heel-to-toe” appearance, while others will appear “toe-to-heel.

Abstract: A pneumatic tire comprising a tread which comprises block-shaped land portions and a plurality of specific sipes formed on the block-shaped land portions is disclosed. At least in one portion in the direction of the depth of the sipe, the sipe has an amplitude in the direction of the width of the sipe and extends in the transverse direction of the tire, and at least one portion of each sipe in the direction of the depth of the sipe is disposed at an offset position relative to an other portion of the sipe in a circumferential direction of the tire. The amplitude of the sipe in the present invention may change in the direction of the depth and the change may alternate from an increase to a decrease or from a decrease to an increase at one or a plurality of node positions disposed in the sipe in the direction of the depth of the sipe.

Abstract: A tread for a tire having, on at least one lateral part, and radially to the inside of the running surface of said tread, a plurality of cavities oriented virtually transversely and opening onto at least one of the edges of the tread, the cavities being intended to form grooves and incisions opening radially towards the outside of the tread after wear of between 15% and 45% of the thickness of the tread when new. Also, a mold adapted for the molding of such a tread pattern and including, on at least one part molding one of the sidewalls, elements in relief for molding cavities radially beneath the running surface of a tread when new.

Abstract: A studless pneumatic tire having excellent running performance of the tire on icy road surfaces. The tire has a plurality of block-shaped island portions formed on a cylindrical tread extending between a pair of sidewalls. The island portions have laterally extending sipes and are separated by a plurality of main grooves extending in the circumferential direction as well as by many lug grooves. Each island portion has a first sipe and a second sipe. The first sipe extends from a first lateral end facing a first main groove to traverse a first edge region of the island portion in a substantially axial direction and branches into a plurality of branch segments, thereby forming a fork-like shape, at a first interface between the first edge region and the central region of the island portion. Each branch segment traverses the central region of the island portion and reaches a point near a second interface between an opposite second edge region and the central region of the island portion.

Abstract: A pneumatic tire has a block pattern of a tread defined by a plurality of circumferential grooves extending in a circumferential direction of the tread and a plurality of lateral grooves each extending across the circumferential grooves and tread ends, wherein specified chamfered face, sipe or fine groove is formed in each block of all block rows to improve a self-aligning torque in the high-speed running of a vehicle.

Abstract: A tire having a ground contacting tread comprising tread grooves which divide the tread into a plurality of tread pattern elements provided on its radially outer surface with a radially outwardly projecting ridge disposed on an edge of the pattern element and at least one radially inwardly projecting small groove extending to the projecting ridge which facilitates the dispersal of trapped air in the molding and vulcanization operation of the tire manufacturing process.

Abstract: A tire for vehicle wheels, provided with a tread band, includes a plurality of raised blocks confined between at least two longitudinal grooves, at least two transverse grooves meeting the longitudinal grooves, and a first and second series of sipes formed in the blocks to divide each block into a plurality of flexible portions. The flexible portions have a grip edge in the form of an acute angle on the outer rolling surface of the tread band. Each of the transverse grooves is confined between a first side, substantially normal to the outer rolling surface of the tread band, and a second side, diverging from the first side toward the outer rolling surface of the tread band. The second side of each of the transverse grooves has an orientation concordant with that of the sipes of a corresponding block, relative to the outer rolling surface of the tread band.

Abstract: A heavy duty tire comprises a pair of axially outermost circumferential rows of shoulder blocks, each of the shoulder blocks provided with a circumferentially extending narrow groove, the narrow groove subdividing the shoulder block into an axially inner wide main part and an axially outer narrow lateral part, and the narrow groove is curved convexly so that the narrow lateral part is narrower in a middle region than both the circumferential end regions, whereby the heel and toe wear and shoulder wear and resistance to tear-off can be improved.

Abstract: A studless tire contains tread portion made of vulcanized rubber, compounded from 100 parts by weight of rubber and 2 to 30 parts by weight of short fibers, and the tread portion has a ground connecting region with sipes, formed by pressing thin plates onto the tread rubber during vulcanizing, whereby the thin plates orient the short fibers in a radial direction. Preferably, the short fibers have a diameter of not more than 30 &mgr;m and a length of from 0.3 to 20 nm, and the thickness of the thin plates or the width of the sipes ranges from 0.2 to 0.5 mm with spacings being sipes less than 10 mm. The short fibers are circumferentially oriented before pressing the thin plates, and the total length in mm of axial component of all sipes ranges from 0.05 to 0.15 times the area in mm2 of ground contacting region.

Abstract: A tread for a vehicle tire includes at least one circumferentially extending longitudinal groove and transverse grooves emanating from the longitudinal groove for defining blocks in a pattern and sipes arranged in the tread. Each sipe defines a sipe depth extending from a pattern face of the tread toward a pattern base of the tread. At least one of the sipes is located in at least one of the blocks and is configured to have legs defining a V-shape. An intersection of the legs is arranged in a side surface area of the block facing the longitudinal groove. Ends of the legs are oriented away from the side surface area.

Abstract: An off-road pneumatic tire 10 having a tread 12 with a plurality of lugs 14, each lug 14 having a wide section 22 near at least one shoulder of the tread and a narrow section 24 crossing a centerline of the tread. In a preferred embodiment, each lug 14 having two wide sections 22, one extending from each shoulder 16, 18 of the tread 12 and being interconnected by the narrow section 24.

Abstract: An off-road pneumatic tire 10 having a plurality of lugs 14 extending from a first shoulder 16 to a second shoulder 18. The plurality of lugs 14 are separated by a plurality of wide grooves 20. The tire 10 has at least a first lug 22 and a second lug 24. The lugs 14 alternate circumferentially between the first lug 22 and the second lug 24. The first lugs 22 has three tread elements 30, 32, 34 separated by a first and second narrow groove 26, 28, and the second lug 24 has two tread elements 36, 38 separated by a third narrow groove 40. In a preferred embodiment, the respective lugs 14 incline from the first shoulder 16 to the second shoulder 18 and are interconnected by wide groove tie bars 44.

Abstract: A pneumatic agricultural tire (20) for an industrial type tractor or like vehicle has a plurality of central lugs (60) and a plurality of shoulder lugs (40, 50). The plurality of central lugs (60) are arranged in a circumferentially continuous row and extend across the equatorial plane (EP). Each central lug (60) is similar in shape and orientation relative to each circumferentially adjacent central lug (60). Each central lug (60) has a leading edge (51) and a trailing edge (52). The leading edges (51) of each lug (60) are located on an opposite of the equatorial plane relative to the trailing edge (52) of the same central lug (60). The plurality of shoulder lugs (40, 50) are divided into first and second rows and project radially outwardly from the inner tread (34) and extend from the lateral tread edges (33A, 33H) toward the equatorial plane of the tire (20).

Abstract: A tread (20) for a pneumatic tire (10) has three distinct traction elements (40, 42, 44) arranged in three circumferential extending rows (2, 4, 6). The middle row (4) has a chevron-shaped traction element (42) oriented in an alternating pattern where a truncated apex (43) and an open end (50) are oriented facing the tread shoulders (24, 26). The two shoulder rows (2, 6) each have a plurality of two distinctly differentially-shaped, laterally extending lugs (40, 44), a first laterally extending shoulder lug (40) which has a narrow axially inner end (41) adjacent an open end (50) of the chevron-shaped traction element (42) and a second laterally extending shoulder lug (44) which has an enlarged axially inner end (45) aligned circumferentially with the truncated apex (43).

Abstract: A pneumatic tire comprises a central longitudinal groove in a tread crown region and an outer longitudinal groove in each tread shoulder region, the longitudinal grooves are crossed by lateral grooves to form crossings and to define blocks on each side of each longitudinal groove, the outer longitudinal grooves are provided near the crossings with tie-bars, the length Tc of each of which is 10 to 40% of the average length of the longitudinal edges of two blocks axially adjacent to the tie-bar, each length measured along the longitudinal groove. Preferably, the lateral grooves in the crown region provided near the crossings with tie-bars, the length Ta of each of which is 10 to 40% of the average length of the lateral edges of two blocks circumferentially adjacent to the tie-bar, each length measured along the lateral groove.

Abstract: An aggressive on/off-road pneumatic tire tread design for recreational vehicles which is highly durable, self cleaning, improves rolling resistance on paved roads, has excellent tread wear characteristics, and is relatively quiet on paved roads. The tread design includes a side wall tread portion including a scuff bar and the area between it and the ground contacting tread is further provided with raised emblems and distinctive markings which provide traction and reduce mud caking, The tire's tread includes a pair of parallel rows of opposing chevron shaped lugs, defining a zigzag channel therebetween, and an outer row of polyhedron shoulder lugs outboard of the chevron rows, the polyhedron lugs being three different sizes, a short, intermediate and long, sequentially arranged in sets of three with a short lug between each long and intermediate lug. Root risers in the lateral channel between each chevron shaped lug are provided to prevent stress crack running in the tread.

Abstract: A heavy duty pneumatic tire has a tread pattern comprising plural block rows, in which each block in at least one block row other than a block row located astride a center of the tread is provided on two corner portions located at a side of a tread end with chamfered regions each gradually decreasing a height of the block toward a tip of the respective corner portion.

Abstract: A pneumatic tire having a block type tread pattern improved in stone trapping, which comprises a tread portion being provided with a mesh of grooves to define a plurality of blocks consisting of shoulder blocks adjacent to the tread edges and central blocks other than the shoulder blocks, each of the central blocks being surrounded by at least one projection standing out from the groove bottom leaving spaces from the groove walls, the projection comprising alternate wide main portions and narrow coupler portions, the height of the wide main portions being 10 to 25% of the groove depth, the height of the narrow coupler portions being 5 to 10% of the groove depth, the length of each of the wide main portions being 3 to 10 mm, the length of each of the narrow coupler portions being 2 to 8 mm, the width of the narrow coupler portions being 0.

Abstract: A heavy duty pneumatic tire comprises a tread portion which is provide with wide circumferential grooves having a width Wm1 of 4.0 mm to 20.0 mm and narrow circumferential grooves having a width Wm2 of not less than 2.0 mm but less than 4.0 mm, and each region which is defined between one of the wide circumferential grooves and the axially adjacent narrow circumferential groove is provided with axial grooves extending from the wide circumferential groove to the narrow circumferential groove to circumferentially divide the region into blocks, wherein the axial grooves include variable-width grooves of which groove width increases from the wide circumferential groove to the narrow circumferential groove.

Abstract: A heavy duty radial tire including a tread portion which is provided with blocks having acute angled corners each defined between a pair of edge lines (3A and 3B) of the block, the acute angled corners being provided with a down slope which becomes steeper from the radially outside to the inside of the tire. Preferably, the size of the slope is 1 to 10 mm along the one edge line (3A), and 1 to 10 mm along the other edge line (3B), and 5 to 13 mm in the radial direction of the tire.

Abstract: The described tread band (1) has laterally opposite transverse channels (6), each having a substantially rectilinear end stretch (6a) extending with an appropriate inclination from a respective outer side edge (1a), a connecting stretch (6c) of curvilinear extension and an inner end stretch (6b) terminating beyond the equatorial plane (X) and having a slightly inclined orientation relative the latter. The connecting stretch (6c) of each transverse channel (6) opens into the connecting stretch of a laterally opposite transverse channel, to define a transverse groove (3) of undulated extension. Also provided are two longitudinal grooves (2) consisting of substantially rectilinear stretches (2a) each extending between two transverse grooves (3) in a direction inclined to the equatorial plane (X). L-shaped auxiliary channels (8) are interposed in an alternate sequence relative to the transverse channels (6) defining grooves (3).

Abstract: A pneumatic tire capable of obtaining a high tire performance on ice without decreasing the other performances can be provided. A plurality of narrow grooves each having a rectangular cross section are formed on one sipe side wall surface of a sipe in an inclined manner at a certain angle. Even when the sipe is closed under a load application to the tire, portions having the narrow grooves are not brought into contact with the other sipe side wall surface of the sipe so that water on an ice road surface can be absorbed and removed by the narrow grooves. Further, in the case of the narrow groove in which one end is opened to a road contact surface portion and the other end is opened to a side surface, the absorbed water can be continuously discharged to an outside of a block in serial order so that the water on the ice road surface can be further removed.

Abstract: An on/off road radial pneumatic light truck or automobile tire has a tread with at least one wide groove having an average width of at least 7% of the tread width. At least two axially adjacent rows of traction elements are separated by the wide groove. The tread has a plurality of protrusions extending from traction elements into the wide groove. The protrusions are sloped radially inwardly at an angle in the range of 20.degree. to 60.degree. relative to the radial direction from the outer surface of the traction element toward the tread base and crossing axially more than halfway across the wide groove width toward an intersection of a lateral groove and the wide groove. The protrusions extending from traction elements on one side of the wide groove are circumferentially offset and at least partially axially aligned with protrusions extending from traction elements on the opposite side of the wide groove.

Abstract: A pneumatic tire comprises a tread portion, the tread portion is provided in a center region with a row of long blocks and wide blocks which are disposed alternately in the circumferential direction of the tire, the center region has 30% of the tread width, the long blocks are such that the circumferential length (a) is larger than the axial length L1, the wide blocks are such that the axial length L2 is larger than the circumferential length (b), the ratio (a/b) of the circumferential length (a) and the circumferential length (b) is 1.1 to 1.5, and the ratio (S1/S2) of the surface area S1 of the long blocks and the surface area S2 of the wide blocks is 0.40 to 0.77. Preferably, the axial length L2 of the wide blocks is 18 to 30% of the tread width, and the long blocks and wide blocks are disposed such that at least one of the long blocks and at least one of the wide blocks appear in the ground contacting patch of the tire.

Abstract: A pneumatic tire comprises: a tread rubber having a Shore A hardness of not more than 65 degrees at 20 degrees C.; a tread portion provided with at least one circumferential row of blocks having circumferential edges adjacent to lateral grooves; each of the circumferential edges having a mean inclination angle of 0 to 60 degrees with respect to the tire axial direction; sidewalls of the lateral grooves on one side in the tire circumferential direction each comprising a first upper slope extending from the top of the adjacent block to a first point at a depth h1, while inclining at an angle .alpha.1, and a first lower slope extending from said first point towards the groove bottom, while inclining at an angle .alpha.2 smaller than the angle .alpha.1,; the remaining sidewalls of the lateral grooves on the other side each comprising a second upper slope extending from the top of the adjacent block to a second point at a different depth h2 than said depth h1, while inclining at an angle .beta.

Abstract: A pneumatic tire comprises a tread portion having a plurality of block-shaped or rib-shaped lands defined by a plurality of tread grooves, wherein each edge portion of the same block-shaped or rib-shaped land located at a boundary between a ground contact region and a side wall of the block-shaped or rib-shaped land is subjected to chamfering convexly outward in a radial direction of the tire at a curvature varied in accordance with a distance from a given position of the block-shaped or rib-shaped land.