Patent ID: 8455582

Claim:
A tire rubber composition, comprising: a rubber component; silica; and a silane coupling agent, wherein said silica has a CTAB specific surface area of 195 m 2 /g or more and a BET specific surface area of 200 m 2 /g or more, and said silane coupling agent is a copolymer comprising units A represented by formula (1) and units B represented by formula (2), and the proportion of the units B is 30 to 60 mol % of the total molar amount of the units A and the units B: wherein x and y each are an integer of one or more, R 1 represents hydrogen, halogen, a branched or unbranched C 1-30 alkyl or alkylene group, a branched or unbranched C 2-30 alkenyl or alkenylene group, a branched or unbranched C 2-30 alkynyl or alkynylene group, or a group in which a hydrogen atom at the end of the alkyl or alkenyl group is replaced with a hydroxy or carboxyl group, R 2 represents hydrogen, a branched or unbranched C 1-30 alkylene or alkyl group, a branched or unbranched C 2-30 alkenylene or alkenyl group, or a branched or unbranched C 2-30 alkynylene or alkynyl group, and R 1 and R 2 may form a ring structure together, wherein the amount of silica is 5 to 150 parts by mass per 100 parts by mass of the rubber component, and the amount of the silane coupling agent is 0.5 to 20 parts by mass per 100 parts by mass of the silica.