The tire (10B) comprises a tread (12) including a running layer (14) which is intended to come into contact with the ground when the tire (10B) rolls on the ground, and a sublayer (16) located radially inwards from the running layer (14). The tread (12) comprises at least one fluid passage (22) between the sublayer (16) and the air surrounding the tire (10B). The sublayer (16) comprises a cellular material. The fluid passage (22) comprises an element chosen from a groove (20) and a cut (26), formed in the running layer (14) and extended by at least one well (28) acting as a radial extension of the element, formed between the groove (20) and/or the cut (26) and the sublayer (16). Each well (28) forms a localized part of the fluid passage (22).

A pneumatic tyre includes a tread portion being provided with a land portion divided by a main groove extending continuously in a tyre circumferential direction. The land portion is provided with two or more sipes having a width less than 1.5 mm on a ground contacting surface of the land portion and two or more groove elements having a width equal to or more than 1.5 mm on the ground contacting surface. Lengths in a tyre axial direction of the groove elements are equal to or less than 15% of a maximum width in the tyre axial direction of the ground contacting surface of the land portion, and at least one of the sipes is in communication with one of the groove elements.

The invention includes methods for forming a retreaded tire and treads there for. Particular embodiments of such methods include providing a tire carcass configured to receive a tire tread along an annular tread-receiving area and a pre-formed tread comprising a tread body and a submerged void arranged along a bottom side of the tread and extending into the tread thickness to a top end located below the top side of the tread, the submerged void having a length and an opening arranged along the bottom side when the tread is in an uninstalled configuration, where the opening of the submerged void extends in a direction of the submerged groove length along an alternating, non-linear path. Further steps include assembling a retreaded tire by arranging the tire tread atop a bonding layer arranged between the tire tread and the tire carcass and comprising uncured bonding material.

Mould for moulding a tread of a tire, this tread having a thickness of material to be worn away and a tread surface intended to come into contact with the road surface when the tire is running, this mould having a moulding surface intended to mould the tread surface of the tread, and having a moulding element formed of a blade and a bar, the blade being attached to the moulding surface to mould a sipe in the tread, the bar, borne by the blade to form an enlarged part of maximum width D, being intended to mould a channel in the tread, this channel itself being intended to form a new groove when the tread becomes part worn. Each blade is delimited by two lateral faces forming between them a mean angle of between 6° degrees and 18°. The blade width decreasing from the mould surface when new, as far as the connection with the bar, the blade width meets the bar being at least equal to between 0.2 and 0.4 times the maximum width D.

The invention includes methods for forming a retreaded tire and treads there for. Particular embodiments of such methods include providing a tire carcass configured to receive a tire tread along an annular tread-receiving area and a pre-formed tread comprising a tread body and a submerged void arranged along a bottom side of the tread and extending into the tread thickness to a top end located below the top side of the tread, the submerged void having a length and an opening arranged along the bottom side when the tread is in an uninstalled configuration, where the opening of the submerged void extends in a direction of the submerged groove length along an alternating, non-linear path. Further steps include assembling a retreaded tire by arranging the tire tread atop a bonding layer arranged between the tire tread and the tire carcass and comprising uncured bonding material.

Provided is a sipe blade for molding a cavity in a tire tread. The sipe blade may comprise an elongated bulb core having an axis of elongation and a peripheral surface and an elongated thin strap. The elongated thin strap may have a first end fixedly mounted to an associated tire tread mold surface, a second end opposite the first end, and may extending substantially normally to the associated tire tread mold surface. The first end and the second end may be connected by a first face. A bulb may be formed from the first face wrapped over the peripheral surface starting from the second end.

A method for producing a tread for a tire having a plurality of contacting element delimited by a plurality of grooves and a connecting member. The method includes depositing at least one connecting member on a surface of an unvulcanized green tread, introducing the unvulcanized green tread with the connecting member into a mold having at least one molding element having a plurality of rib for forming the groove on the tread, at least two rib side faces and a molding surface, at least one rib having at least one notching portion receiving a guiding member including a guiding slit, moving the connecting member to a predetermined position in the guiding slit through the guiding slit by green tread, molding and vulcanizing the green tread with the connecting member in the mold, and taking a molded and vulcanized tread out from the mold.

Mould for moulding a tread of a tire, this tread having a thickness of material to be worn away and a tread surface intended to come into contact with the road surface when the tire is running, this mould having a moulding surface intended to mould the tread surface of the tread, and having a moulding element formed of a blade and a bar, the blade being attached to the moulding surface to mould a sipe in the tread, the bar, borne by the blade to form an enlarged part of maximum width D, being intended to mould a channel in the tread, this channel itself being intended to form a new groove when the tread becomes part worn. Each blade is delimited by two lateral faces forming between them a mean angle of between 6 degrees and 18. The blade width decreasing from the mould surface when new, as far as the connection with the bar, the blade width meets the bar being at least equal to between 0.2 and 0.4 times the maximum width D.

A pneumatic tyre includes a tread portion being provided with a land portion divided by a main groove extending continuously in a tyre circumferential direction. The land portion is provided with two or more sipes having a width less than 1.5 mm on a ground contacting surface of the land portion and two or more groove elements having a width equal to or more than 1.5 mm on the ground contacting surface. Lengths in a tyre axial direction of the groove elements are equal to or less than 15% of a maximum width in the tyre axial direction of the ground contacting surface of the land portion, and at least one of the sipes is in communication with one of the groove elements.

The liming element for a tire mould comprises a body 12 delimiting a moulding surface 14 intended to at least partially mould a rolling surface of the tire, at least one injection nozzle 26 arranged on the body and provided with at least one outlet orifice 26a, at least one supply duct extending inside the body and the injection nozzle while being in communication with the said outlet orifice, and at least one shut-off member 30 mobile with respect to the injection nozzle between an outlet orifice closed position and an outlet orifice open position. The body 12, the injection nozzle 26 and the shut-off member 30 are manufactured by the deposition and selective melting of stacked layers of powder.