Patent ID: 7249621

Claim:
A pneumatic tire with a tread having an outer running surface comprised of a rubber composition which contains at least one conjugated diene-based elastomer to the exclusion of isobutylene copolymer rubbers comprised of, based upon parts by weight per 100 parts by weight of rubber (phr): (A) about 60 to 100 phr of at least one conjugated diene-based elastomer having a Tg below −30° C. and, correspondingly, zero to about 40 phr of at least one diene-based elastomer having a Tg of −30° C. or above; (B) about 0.1 to about 30 phr of corncob granules comprised of granules of the woody ring of corncobs, wherein at least 90 percent of said corncob granules have an average diameter in a range of from about 20 to about 500 microns; (C) about 30 to about 110 phr of reinforcing filler comprised of: (1) from about 30 to about 80 phr of amorphous, synthetic precipitated silica aggregates containing hydroxyl groups on the surface thereof and (2) from about 30 to about 80 phr of rubber reinforcing carbon black, and wherein said rubber composition additionally contains a coupling agent having a moiety reactive with hydroxyl groups on said corncob granules and said hydroxyl groups on said precipitated silica and another moiety interactive with at least one of said conjugated diene-based elastomer(s).