Tire with tread base rubber blend

A rubber tire having a rubber tread of a cap/base construction where said base rubber composition is comprised of, based on 100 parts by weight rubber, (A) about 50 to about 95 parts by weight of at least one diene rubber selected from natural and/or synthetic cis 1,4-polyisoprene rubber, cis 1,4-polybutadiene rubber, styrene/butadiene copolymer rubber, styrene/isoprene/butadiene terpolymer rubber and 3,4-polyisoprene rubber;

• and (B) about 5 to about 50 parts by weight of a trans 1,4-polybutadiene rubber characterized by having about a 75 to about a 85 percent trans 1,4-content, about a 12 to about an 18 percent 1,2-content and about a 3 to about an 8 percent cis 1,4-content and, in its uncured state, a first major melting point in the range of about 35.degree. C. to about 45.degree. C. and a second minor melting point in the range of about 55.degree. C. to about 65.degree. C.

A method of preparing a pneumatic rubber tire with a rubber tread of a cap/base construction which comprises shaping and curing an uncured pneumatic rubber tire in a mold by pressing said tire outwardly against a mold surface under conditions of heat and pressure to cause at least the tread rubber of said tire to flow and cure against said mold surface, the improvement which said rubber tread has a base rubber composition of, based on 100 parts by weight rubber, (A) about 50 to about 95 parts by weight of at least one diene rubber selected from natural and/or synthetic cis 1,4-polyisoprene rubber, cis 1,4-polybutadiene rubber, styrene/butadiene copolymer rubber, styrene/isoprene/butadiene terpolymer rubber and 3,4-polyisoprene rubber;

• and (B) about 5 to about 50 parts by weight of a trans 1,4-polybutadieen rubber characterized by having at least about a 70 percent trans 1,4-content.