Bridgestone Corporation

Mitsuru Araki

Yoshiyuki Morimoto

A pneumatic tire has a tread with a rubber composition produced by blending a rubber component with a styrene based thermoplastic elastomer. The rubber component is composed mainly of a diene based rubber, and the elastomer is so preliminarily internally crosslinked that tensile stress at a 100% elongation is increased to 10 to 1,000% of that of the styrene based thermoplastic elastomer not internally crosslinked. A pneumatic tire is also disclosed, having a tread portion with a rubber composition blended with a vinyl aromatic hydrocarbon thermoplastic elastomer in an amount of 5-80 parts by weight relative to 100 parts by weight of the rubber component. The vinyl aromatic hydrocarbon thermoplastic elastomer satisfying the following requirements: (1) the elastomer is a vinyl aromatic hydrocarbon-conjugated diene based block type thermoplastic elastomer; (2) the elastomer has a weight ratio between a vinyl aromatic hydrocarbon and a conjugated diene as constituent monomer units thereof being 40/60 to 95/5; (3) a content percentage of the vinyl aromatic hydrocarbon in vinyl aromatic hydrocarbon based segments in the elastomer is not less than 50% by weight; and (4) a weight average molecular weight of the elastomer is not less than 1.times.10.sup.5.

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Hachioji, Japan

Mitsuru Araki