Truck tire with rubber tread

A pneumatic tire with a circumferential tread having a cap/base configuration comprised of an outer tread cap rubber layer and an internal rubber layer underlying said outer tread cap rubber layer rubber, wherein the rubber composition of said tread cap rubber layer is comprised of, based on parts by weight per 100 parts by weight rubber (phr):

• (A) elastomers comprised of
• (1) about 65 to about 90 phr of cis 1,4-polyisoprene rubber,
• (2) about 5 to about 25 phr of cis 1,4-polybutadiene rubber,
• (3) zero to about 12 phr of 3,4-polyisoprene rubber and
• (4) optionally up to about 20 phr of at least one additional rubber selected from polymers of at least one of isoprene and 1,3-butadiene and copolymers of styrene and at least one of isoprene and 1,3-butadiene,
• (B) about 1 to about 8 phr of salt of at least one fatty acid comprised of the product of at least one of stearic, palmitic and oleic acid and at least one of zinc oxide, magnesium oxide and calcium carbonate,
• (C) zero to about 20 phr of hydrocarbon resin,
• (D) about 45 to about 70 phr of reinforcing filler comprised of:
• (1) precipitated silica having a nitrogen surface area (BET) in a range of from about 210 to about 225 m2/g, together with a coupling agent for said precipitated silica having a moiety reactive with hydroxyl groups (e.g. silanol groups) on said precipitated silica and another, different, moiety interactive with said elastomer(s), or
• (2) a combination of rubber reinforcing carbon black and said precipitated silica containing from about 2 to about 15 phr of said rubber reinforcing carbon black, together with coupling agent for said precipitated silica having a moiety reactive with hydroxyl groups on said precipitated silica and another, different, moiety interactive with said elastomer(s), and
• (E) curative for said rubber composition comprised of sulfur and sulfur cure accelerator where said sulfur cure accelerator is comprised of a combination of primary sulfur cure accelerator and secondary sulfur cure accelerator,
• where said primary sulfur cure accelerator is comprised of at least one of N-tertbutyl-2-benzothiazolesulfenamide and N—N-dicyclohexyl-2-benzothiazolesulfenamide, and
• where said secondary sulfur cure accelerator is comprised of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane.