Isoprene-butadiene rubber

The subject invention discloses an isoprene-butadiene rubber which is particularly valuable for use in making truck tire treads, said rubber being comprised of repeat units which are derived from about 20 weight percent to about 50 weight percent isoprene and from about 50 weight percent to about 80 weight percent 1,3-butadiene, wherein the repeat units derived from isoprene and 1,3-butadiene are in essentially random order, wherein from about 3% to about 10% of the repeat units in said rubber are 1,2-polybutadiene units, wherein from about 50% to about 70% of the repeat units in said rubber are 1,4-polybutadiene units, wherein from about 1% to about 4% of the repeat units in said rubber are 3,4-polyisoprene units, wherein from about 25% to about 40% of the repeat units in the polymer are 1,4-polyisoprene units, wherein the rubber has a glass transition temperature which is within the range of about -90 DEG C to about -75 DEG C, and wherein the rubber has a Mooney viscosity which is within the range of about 55 to about 140. The isoprene-butadiene rubber of this invention will preferably have a Mooney viscosity which is within the range of about 85 to about 130 and will more preferably have a Mooney viscosity which is within the range of about 115 to about 125.