Transverse grooves providing venting in treads for retreaded tires

A method of forming a tire tread for a retread tire comprising:

• providing a mold comprising:
• a first mold portion and a second mold portion cooperatively positionable together to form a cavity there between for molding a retread having a retread thickness formed of a plurality of tread wear layers,
• the first mold portion including a top interior surface for forming a top side of the retread thickness configured to engage a ground surface during tire operation,
• the second mold portion including a bottom interior surface for forming a bottom side of the retread thickness configured to attach to a tire carcass,
• the mold including a first interior side surface for forming a first side edge of the retread thickness and a second interior side surface for forming a second side edge of the retread thickness respectively, each extending longitudinally in a lengthwise direction of the retread, and where a width along the top interior surface between the first side edge and the second side edge is less than a width along the bottom interior surface between the first side edge and the second side edge;
• arranging a bottom longitudinal groove core within the mold to project into the cavity, the bottom longitudinal groove core being positioned to form a corresponding bottom longitudinal groove arranged within one tread wear layer of a plurality of tread wear layers and in fluid communication with the bottom side of the retread thickness;
• arranging a recessed lateral groove core in operable connection with the bottom interior surface of the second mold portion, the lateral groove core being arranged to extend from the first interior side surface and engage the bottom longitudinal groove core at least when the first mold portion and the second mold portion are positioned together, the recessed lateral groove core being arranged a distance below the top interior surface of the first mold portion;
• and,
• molding tread material in the retread having the retread thickness, the retread thickness including a lateral groove in the retread formed by the lateral groove core, the lateral groove in fluid communication with the bottom side of the retread thickness to form a vent passageway in the retread thickness from the bottom longitudinal groove to the first side edge of the retread thickness without the lateral groove intersecting a top longitudinal groove and without the lateral groove being in fluid communication with the top side of the retread thickness, such that the top longitudinal groove is offset from the lateral groove within the retread thickness without any opening connecting the top longitudinal groove to the lateral groove and wherein a connecting portion core extends between the lateral groove core and the bottom interior surface of the second mold portion, the connecting portion core having a width less than a width of the lateral groove core.

A mold for forming a tire tread for a retread tire comprising:

• a first mold portion and a second mold portion cooperatively positionable together to form a cavity there between for molding a plurality of tread wear layers forming a retread thickness of a retread,
• the first mold portion including a top interior surface for forming a top side of the retread thickness configured to engage a ground surface during tire operation,
• the second mold portion including a bottom interior surface for forming a bottom side of the retread thickness configured to attach to a tire carcass,
• the mold including a first interior side surface and a second interior side surface for forming a first side edge of the retread thickness and a second side edge of the retread thickness respectively, each extending longitudinally in a lengthwise direction of the retread, and where a width of the retread along the top side between the first side edge and the second side edge is less than a width of the retread along the bottom side between the first side edge and the second side edge, the mold including a top longitudinal groove core for forming a top longitudinal groove,
• the mold including a bottom longitudinal groove core projecting into the cavity positioned for forming a bottom longitudinal groove arranged within one tread wear layer of a plurality of tread wear layers and in fluid communication with the bottom side of the retread thickness,
• a lateral groove core in operable connection with the bottom interior surface projecting into the cavity extending from the first interior side surface in contacting engagement with the bottom longitudinal groove core when the first mold portion and the second mold portion are positioned together,
• the lateral groove core for forming a lateral groove in fluid communication with the bottom side of the retread thickness forming a vent passageway in the retread thickness from the bottom longitudinal groove in the retread thickness through the first side edge of the retread thickness without the lateral groove intersecting a top longitudinal groove and without the lateral groove being in fluid communication with the top side of the retread thickness, such that the top longitudinal groove is offset from the lateral groove within the retread thickness without any opening connecting the top longitudinal groove to the lateral groove and wherein a connecting portion core extends between the lateral groove core and the bottom interior surface of the second mold portion, the connecting portion core having a width less than a width of the lateral groove core.