Constrained post cure inflation

Method of constrained post cure inflation for a radial ply tire having beads, ply cords, and a tread;

• the method comprising the steps of:
• initiating the method of constrained post cure inflation on the radial ply tire after the radial ply tire has been removed from a tire curing mold;
• providing a constrained post cure inflation device having a 360 degree circumferential tread restraint device having a 360 degree tread restraint surface disposed at an equal radial distance from a central axis through the constrained post cure inflation device, the tread restraint surface being formed from a plurality of segmented tread restraint plates adapted to hold the tread of the tire in a predefined ideal tread shape, concentric to an axis of rotation and nominally perpendicular to an equatorial plane of the tire;
• opening the plurality of segmented tread restraint plates radially outward from the central axis;
• inserting the radial ply tire into the constrained post cure inflation device so that the beads are sealingly held concentric to, and equidistant from, the axis of rotation, and symmetrically spaced about the equatorial plane;
• closing the plurality of segmented tread restraint plates radially inward toward the central axis;
• inflating the tire to a controlled pressure to simultaneously press the tread of the tire against the 360 degree tread restraint surface;
• and
• holding the controlled pressure for a controlled time while at least a portion of the ply cords are at a controlled temperature above a glass transition temperature of the ply cord material so that the ply cord stresses are normalized.