Rubber composition for tire and method of manufacturing same

A method for manufacturing a pneumatic tire from a rubber composition comprising 100 parts by weight of a diene rubber, 1 to 30 parts by weight of an expandable graphite having a particle size of 30 to 600 μm and curing agents comprising the steps of:

• mixing the diene rubber with other components except for the expandable graphite and the curing agents;
• adding thereto the expandable graphite and the curing agents in the separate mixing step (i.e., final mixing) under such a condition that the maximum reaching temperature is below the expansion onset temperature of the expandable graphite, followed by extrusion processing under the substantially same temperature condition as in the final mixing;
• and then
• assembling a green tire with the extrude of the rubber mixture, and then, vulcanizing the green tire having the extruded rubber mixture at a temperature of more than the expansion onset temperature of the expandable graphite.