Rubber composition for tires and pneumatic tire

A rubber composition for tires, consisting of a diene rubber, non-aggegated silica, a sulfur-containing silane coupling agent and an alkyltriethoxysilane represented by formula (I) below, wherein

• 50 mass % or more of the diene rubber is a styrene-butadiene copolymer rubber,
• the sulfur-containing silane coupling agent has a mercapto group,
• the content of the silica is from 5 to 150 parts by mass per 100 parts by mass of the diene rubber,
• the content of the sulfur-containing silane coupling agent is from 3 to 15 mass % relative to the content of the silica, and
• the content of the alkyltriethoxysilane is from 0.1 to 20 mass % relative to the content of the silica and has the formula;
• in the formula, R1 is an alkyl group having 7 to 20 carbon atoms, and
• wherein the silica has a CTAB adsorbtion specific surface area of greater than 160 m2/g,
• and
• additives selected from the group consisting of fillers excluding aggregated silica, crosslinking agents, crosslinking accelerators, zinc oxide, oils, anti-aging agents, plasticizers and mixtures thereof.