Tire with component comprised of rubber composite of styrene/butadiene elastomer containing pendent silanol and/or siloxy groups

A tire having at least one component of a rubber composition comprised of, based upon 100 parts by weight of elastomer (phr),

• (A) 100 phr of elastomers comprised of:
• (1) about 30 to about 80 phr of a styrene/butadiene elastomer composite (SBR Composite) comprised of a styrene/butadiene elastomer (SBR-1) and a functionalized styrene/butadiene elastomer (SBR-2) which contains at least one silicon atom within said elastomer, and pendent silanol and/or siloxy groups therefrom, and as a part of the elastomer chain to thereby divide said elastomer into at least two segments thereof (SBR-2A and SBR-2B) with the silicon atom a of said pendent silanol and/or siloxy group therebetween, wherein said SBR Composite is thereby comprised of a polymodal molecular weight configuration comprised about 35 to about 55 weight percent thereof (SBR-1) having a number average molecular weight (Mn) in a range of about 200,000 to about 300,000 and, correspondingly, about 65 to about 35 weight percent thereof of said (SBR-2) having a number average molecular weight (Mn) in a range of about 400,000 to 550,000;
• wherein said SBR Composite contains from zero to a maximum of ten weight percent of at least one additional styrene/butadiene elastomer (SBR-3) pendent from said silicon atom having an number average molecular weight (Mn) of greater than 550,000, alternatively between 550,000 and about 650,000 and having styrene contend and Tg values in the range thereof of said SBR-2 and SBR-2;
• (2) about 20 to about 70 phr of at least one additional diene-based elastomer;
• and
• (B) about 35 to about 100 phr of particulate reinforcement comprised of
• (1) about 35 to about 85, phr of at least one of synthetic amorphous precipitated silica and silica treated carbon black which contains domains of silica on its surface, and mixtures thereof, wherein said synthetic silica and said silica domains contain hydroxyl groups on their surfaces, and
• (2) from zero to about 15 phr of carbon black,
• (C) a coupling agent having:
• (1) a moiety reactive with
• (a) said hydroxyl groups contained on the surface of said silica and silica treated carbon black;
• and
• (b) said silanol and/or siloxy groups of said SBR Composite, and;
• (2) another moiety interactive with the polybutadiene portion of said SBR Composite and with said additional diene-based elastomer;
• and:
• (D) about 2 to about 10 phr of a starch/plasticizer composite comprised of starch and plasticizer therefor of a weight ratio in a range of about 0.05/1 to about 4/1, wherein said starch/plasticizer composite has a softening point in a range of about 110° C. to about 170° C. or
• said coupling agent as a combination of a bis-(3-triethoxysilylpropyl) polysulfide having an average of from 2 to 2.5 connecting sulfur atoms in its polysulfidic bridge and a bis-(3-triethoxysilylpropyl) polysulfide having an average of from 3 to 4 connecting sulfur atoms in its polysulfidic bridge, wherein said polysulfide having an average of from 2 to 2.5 connecting sulfur atoms it its polysulfidic bridge is blended with said rubber composition in the absence of sulfur and sulfur vulcanization accelerator and wherein said polysulfide having an average of from 3 to 4 connecting sulfur atoms in its polysulfidic bridge is thereafter blended with said rubber composition in the presence of sulfur and at least one sulfur vulcanization accelerator.