Mold and method of molding annular tread

An annular mold for curing an annular ring tread is disclosed. The annular mold has a plurality of radially movable and outwardly expandable inner segments for forming the inner surface of the tread and a plurality of radially movable and inwardly contracting outer segments for forming the tread outer surface. The radially outer segments are parallelograms. Each outer segment when in a closed molding position spans across one full radially inner segment and portions of two adjacent inner segments. The radially outer segments have inclined laterally extending edges relative to the axial direction of the mold while the circumferentially extending axially outer edges are perpendicular to the axial direction of the mold. The inclined laterally extending edges are inclined at least 5°, preferably about 10° relative to the axial direction. In the preferred embodiment the mold has 12 outer segments, each segment being of an arc length of about 30°.