A method of making a tire includes placing substantially circular sheets of polymeric material on top of each other until a tire is built to a predetermined width. A predetermined tread shape is formed along a circumference of the substantially circular sheets of polymeric material.

A tyre includes a tread portion including a tread surface which is provided with grooves. At least one of the grooves includes a widening-width portion at least partially. The widening-width portion includes a first groove portion extending inwardly in a tyre radial direction from the tread surface, and a second groove portion located inwardly in the tyre radial direction of the first groove portion and having a groove width greater than that of the first groove portion.

A groove of tire thread having a plurality of first and second portions, each delimited by facing walls spaced apart by a maximum width measured at the tread surface and approaching one another such that, at a depth between 20 and 80% of the total depth they are spaced apart by a width less than the maximum width or facing walls spaced apart by a minimum width measured at the tread and diverge from one another such that, at a depth between 20% and 80% of the total depth of the groove, they are spaced apart from one another by a width greater than the width. A plurality of first and second portions of groove so as to form a continuous passage between all the portions of groove in order to allow liquid to flow in the groove regardless of the level of wear.

A tire tread for a heavy-duty vehicle which when new, has a maximum thickness of material to be worn away during running, a tread surface, side faces, a middle region (RM), this tread provided with tread pattern elements having channels, sipes, radial openings and blocking devices, the channels arranged in the tread and connected to the tread surface by radial openings arranged alternating with the blocking devices along the channels, where the tread is devoid of a circumferential groove, the channels arranged below the tread surface when the tread is new, the channels are transverse channels and connect RM to the side faces; each channel connecting the middle region to a side face has a direction change between RM and the side face; and maximum longitudinal distance between points of a transverse channel furthest apart in longitudinal direction is between 10% and 50% of the width of the tread (Lbdr).

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.

Tread with longitudinally oriented grooves (31, 41, 42) at least one is wavy (31) opening onto tread surface (10), at least one rib (21) oriented in the longitudinal direction and delimited by (31) with external cavities (311) opening to tread surface and internal cavities (312) hidden within the thickness of the tread, cavities (311) opening onto the surface (10) when new with a contour (310) having farthest-spaced endpoints A and B separated by a distance Lm, the rib (21) of width Ln having transverse sipes (5), made at a mean pitch Pi, where the length Lm of contour (310) of cavity (311) is equal to or greater than an integer multiple N of the pitch Pi times an amount at most equal to 25% of this integer multiple N of the pitch Pi, when new, N+1 transverse sipes (5) of rib (21) open into cavity (311) bordering the rib.

A heavy-duty vehicle tire tread to improve resistance to chunking of the oblique sipes opening into the external cavities thereof and having at least one substantially longitudinal cut (3) with at least one external cavity (6) open onto the tread surface (2) along an open section (7) having a closed contour (8). Each cavity (6) is connected to two substantially longitudinal sipes (91) and to an oblique sipe (92) having a mean plot (M2) intersecting the contour (8) at a connection point (I). The mean plot (M2) forms an angle (A1, A2) strictly greater than 90° with at at least two straight lines (T1, T2) tangential to the contour (8) respectively at two points (I1, I2) of the contour (8) that are positioned on either side of the mean plot (M2) and at a curvilinear distance (d1, d2) from the connection point (1) at most equal to 2 mm.

A tire tread including a tread surface adapted to come into contact with a road surface has at least one main groove that, when new, opens onto the tread surface of the tread, this main groove having a maximum depth. The main groove includes a plurality of first groove portions and a plurality of second groove portions, the first and second groove portions being arranged alternately such that a first portion is followed by a second portion. Each first groove portion has a width that decreases with wear, and each second groove portion has a width that increases with wear.

Heavy-duty vehicle tire, with tread (1) of thickness E of wearable material and surface (10) for contact with a roadway, tread (1) having a raised element (41, 42) with of sipes (5) circumferentially distributed and inclined. Tread (10) material is an elastomer based on natural rubber or synthetic polyisoprene with a majority of cis-1,4 linkages and on a reinforcing filler predominantly of silica, with a content expressed in phr (parts by weight per hundred parts of elastomers) of greater than 40 and a filler content in phr of greater than 50, and having: a tan(δ)max/(G*25%) ratio at most of 0.065, in which tan(δ) is the measurement, at 60° C., of the loss factor of the tread material, and G*25% is the complex dynamic shear modulus, expressed in MPa, and a deformation at break under tensile testing at least equal to 530%, at a temperature of 60° C.

Tire comprising a tread (1) having sipes (5) having a non-zero inclination with a plane perpendicular to the tread surface (10). The tread is an elastomer compound based on natural rubber or synthetic polyisoprene with a majority of cis-1,4 linkages, the natural rubber or the synthetic polyisoprene in case of a blend being present in a majority amount relative to the amount of the other diene elastomer(s) used and on a reinforcing filler consisting predominantly of silica, with a content expressed in phr (parts by weight per hundred rubber) of greater than 40 and an overall filler content expressed in phr of greater than 50, this material having a tan(δ)max/(G*25%) ratio at most equal to 0.065, in which tan(δ)max is the measurement, at 60° C., of the loss factor of the material of which the tread is made, and G*25% is the complex dynamic shear modulus, expressed in MPa, of this material, and a deformation at break which is at least equal to 530%, this value being obtained at a temperature of 60° C.