Rigid core and method for manufacturing pneumatic tire using same

A rigid core comprising:

• a ring-shaped core main body having a tire molding surface for molding an inner surface of a pneumatic tire;
• the core main body comprising a plurality of circumferentially divided core segments each movable along a tire radial direction;
• and
• each core segment comprising an outer surface forming the tire molding surface as a surface which is in contact directly with a rubber of a pneumatic tire to be molded during a tire vulcanizing process, wherein:
• the outer surface of each core segment comprises:
• an upper portion located radially outward with respect to a maximum width position of the core segment, wherein the upper portion is used to mold an inside of tread and shoulder portions of the pneumatic tire, and
• a lower portion located radially inward with respect to the maximum width position of the core segment, wherein the lower portion is used to mold an inside surface of sidewall and bead portions of the pneumatic tire, and wherein:
• the lower portion has a surface roughness Ra in a range of not less than 10 μm, and
• the upper portion has a surface roughness greater than that of the lower portion and not more than 20 μm.