Patent ID: 8686085

Claim:
A rubber composition comprising: a rubber component; 1 to 8 parts by mass of a mixture of a zinc salt of an aliphatic carboxylic acid and a zinc salt of an aromatic carboxylic acid per 100 parts by mass of the rubber component; and 10 to 150 parts by mass of silica per 100 parts by mass of the rubber component, the rubber component consisting essentially of a natural rubber and a butadiene rubber, said butadiene rubber being modified by a compound represented by the formula (1): wherein R 1 , R 2 and R 3 are the same or different and independently represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group, a mercapto group, or a derivative thereof, and at least one of R 1 , R 2 and R 3 independently represent an alkoxy group; R 4 and R 5 independently represent an ethyl group; and n represents an integer of 1 to 5.