Tire with tread of cis 1,4-polybutadiene-rich rubber composition which contains a functional styrene/butadiene elastomer, silica and coupling agent

Tire has component(s) of rubber composition containing elastomer(s), particulate reinforcement and coupling agent. Elastomer(s) contain styrene/butadiene elastomer composite (SBR composite), cis-1,4-polybutadiene rubber and additional diene-based elastomer. SBR composite contains rubbers SBR-1, SBR-2 and SBR-3. Particulate reinforcement contains aggregates of precipitated silica and carbon black. The tire has component(s) of a rubber composition. The rubber composition contains (in weight parts) elastomers (100), particulate reinforcement (35-100) and coupling agent. The elastomers contain styrene/butadiene elastomer composite (SBR composite) (30-70), cis-1,4-polybutadiene rubber (35-55) and additional diene-based elastomer (5-15). The SBR composite comprises polymodal molecular weight configuration containing styrene/butadiene copolymer rubber (SBR-1) (35-55 wt.%), functional styrene/butadiene copolymer rubber (SBR-2) (65-35 wt.%) and additional styrene/butadiene copolymer segment (SBR-3) (0-10 wt.%). A portion of the rubber (SBR-2) contains at least one silanol and/or siloxy group, with associated pendent hydroxyl and/or alkoxy groups, and segments (SBR-2A and SBR-2B). The silicon atom of silanol and/or siloxy group is between the segments. The number average molecular weight of rubbers (SBR-1, SBR-2 and SBR-3) are 200000-300000, 400000-550000 and greater than 550000, respectively. The rubber (SBR-3) is appended to silicon atom of rubber (SBR-2). The additional diene-based elastomer is chosen from cis-1,4-polyisoprene rubber, 3,4-polyisoprene rubber and trans-1,4-polybutadiene rubber. The particulate reinforcement contains aggregate of precipitated silica (35-85) and carbon black (0-15). The aggregate of precipitated silica comprises several individual elementary silica particles containing hydroxyl groups, preferably silanol groups. The coupling agent is bis(3-triethoxysilylpropyl) polysulfide having an average of 2-2.5 connecting sulfur atoms in its polysulfidic bridge to be exclusive of a bis(3-trialkoxysilyalkyl) polysulfide having an average connecting sulfur atom greater than 3 in its polysulfidic bridge.