Embodiments of the invention include a mold for forming a tire tread. The mold includes a tongue forming portion at an end of a tread forming portion. The tongue forming portion has a substantially constant thickness, except for a portion at an end of the tongue forming portion having a thickness greater than a thickness of a remainder of the tongue forming portion.

A compression press is provided, comprising: a frame; a movable lid carried by said frame and having an opening extending therethrough; an enclosure carried by said frame and comprising a core movable between a retracted position and an extended position, with said core aligned with the opening in said lid; a first hydraulic stage carried by said frame; and a second hydraulic stage carried by said frame and configured to apply additional pressure on said lid and said core in the extended position within the cavity. The first hydraulic stage is configured to perform the following: move said core from the retracted position to the extended position and move said lid and said core in the extended position to contact a mold having a cavity with material deposited therein, with pressure being applied to said lid and said core in the extended position within the cavity.

A compression molding system includes a first extruder to output melted plastic, and a second extruder downstream from the first extruder to mix the melted plastic with wood chips to output a composite material. A transfer valve alternately directs the composite material between inner block molds and outer block molds. Each inner block mold has an inner block press associated therewith to press the composite material into a desired shape of an inner block having an opening on one side. Each outer block mold has an outer block press associated therewith to press the composite material into a desired shape of an outer block having an opening on one side. A press assembly presses one of the inner blocks into the opening in one of the outer blocks to form a double wall block.