RUBBER COMPOSITION FOR TIRES

Provided is a rubber composition for a tire having excellent performance on snow, wet grip performance, and forming processability, while containing a large amount of silica. The rubber composition contains: in 100 parts by mass of a diene rubber containing from 25 to 50 mass % of a butadiene rubber, 50 parts by mass or more of a plasticizer component; from 120 to 180 parts by mass of silica; Mparts by mass of 3-octanoylthio-1-propyltriethoxysilane; and Mparts by mass of alkylsilane. (M+M), a total of the 3-octanoylthio-1-propyltriethoxysilane and the alkylsilane, is from 5 to 10 mass % with respect to the mass of the silica, and [M/(M+M)], a ratio of the alkylsilane with respect to the total of the 3-octanoylthio-1-propyltriethoxysilane and the alkylsilane, is from 0.10 to 0.40.