Abstract: This invention relates to a natural rubber-rich rubber composition and tire with tread thereof. A partial replacement of the natural rubber in the natural rubber-rich tire tread is accomplished by an inclusion of a specialized trans 1,4-styrene/butadiene copolymer rubber characterized by having a combination of bound styrene content and microstructure limitations. The tire tread rubber composition is comprised of a blend of the specialized trans 1,4-styrene/butadiene rubber and cis 1,4-polyisoprene natural rubber optionally together with at least one additional diene-based elastomer in which the natural rubber remains a major portion of the elastomers in the tread rubber composition. A significant aspect of the invention is a partial replacement of natural cis 1,4-polyisoprene rubber in the tread rubber composition.

Abstract: The invention is directed to a pneumatic tire having at least one component comprising a vulcanizable rubber composition, wherein the vulcanizable rubber composition comprises, based on 100 parts by weight of elastomer (phr), from about 30 to 100 phr of high trans random IBR, and from about zero to about 70 phr of at least one additional elastomer, wherein the high trans random IBR comprises from about 3 to about 12 percent by weight of isoprene.