A tire is provided having a circumferential tread of a diene-based rubber composition reinforced with a silica-containing carbon black which contains domains of silica on its surface prepared by extended reactive mixing of said silica-containing carbon black with a coupling agent together with at least one elastomer. Said silica-containing carbon black is a carbon black which contains silica domains on its surface and said silica contains hydroxyl groups (e.g. silanol groups) on its surface, wherein said silica domains cover at least 50 percent of the carbon black surface. Said coupling agent is a bis(3-triethoxysilylpropyl) polysulfide having an average of from 2 to 4, alternately a more limited average of from 2 to 3 or from 2 to 2.6, connecting sulfur atoms in its polysulfidic bridge. In one aspect of the invention, it is preferred that said coupling agent is exclusive of a bis(3-trialkoxysilylalkyl) polysulfide having an average of greater than 3.5 sulfur atoms in its polysulfidic bridge.