Pneumatic tire including cap tread portion

Abstract

A pneumatic tire in which the cap tread portion is composed of a rubber composition comprising (i) 100 parts by weight of a diene rubber having a glass transition temperature (Tg) of not more than -45.degree. C. and (ii) not more than 65 parts by weight of carbon black having a nitrogen specific surface area (N.sub.2 SA) of not less than 140 m.sup.2 /g, a DBP oil absorption of not less than 120 ml/100 g, a .DELTA.DBP of not less than 30 ml/100 g, and a half value (.DELTA.Dst) of distribution of aggregates, measured by a centrifugal precipitation method, of not more than 50 m.mu., or a pneumatic tire in which a cap tread portion is composed of a rubber composition comprising (A) 100 parts by weight of a rubber component mainly comprising natural rubber and polybutadiene rubber and having a hardness at 0.degree. C. of not more than 60 and (B) (i) carbon black having a nitrogen specific surface area (N.sub.2 SA) of not less than 120 m.sup.2 /g and a 24M4DBP of not less than 90 ml/100 g and (ii) a silica in an amount of 5 to 40 parts by weight, with the total weight of the carbon black and silica being not more than 60 parts by weight.

Dependencies are inferred from the claim text.