Rubber composition and heavy duty pneumetic tire using the rubber composition

A rubber composition obtained by compounding (A) a rubber component comprising 15 to 55% by weight of (i) a modified styrene-butadiene copolymer rubber which is obtained by solution polymerization and has a tin atom introduced into its molecular chain, 45 to 85% by weight of (ii) at least one rubber selected from natural rubber and synthetic isoprene rubbers, and (B) a hydrazide compound. The rubber composition exhibits improved abrasion resistance, heat resistance and low heat generating property and is advantageously used for tread rubber of heavy duty pneumatic tires.