Tire with silica reinforced tread and/or sidewall components

A method of preparing a rubber composition which comprises, based upon 100 parts by weight (phr) of diene-based elastomers, (A) blending (1) about 20 to about 60 phr of cis 1,4-polyisoprene elastomer having a Tg in a range of about -65.degree. C. to about -75.degree. C. and (2) about 40 to about 80 phr of (a) trans 1,4-polybutadiene rubber having a Tg in a range of about -70.degree. C. to about -80.degree. C. and cis 1,4-polybutadiene rubber having a Tg in a range of about -100.degree. C. to about -110.degree. C. in a weight ratio of trans 1,4-polybutadiene to cis 1,4-polyisoprene in a range of about 3/1 to about 1/3 or (b) cis 1,4-polybutadiene rubber having a Tg in a range of about -100.degree. C. to about -110.degree. C., (B) about 40 to about 80 phr of carbon black and precipitated silica reinforcing filler comprised of about 20 to about 60 phr of precipitated silica and about 15 to about 60 phr of carbon black and (C) at least one silica coupling agent having a moiety reactive with silanol groups on the surface of the said silica and an additional moiety interactive with the said elastomers and (D) zero to about 10 phr of rubber processing oil;

• wherein said carbon black is selected from a first carbon black having a DBP value in a range of about 100 to about 150 cc/100 gm and an Iodine Number in a range of about 90 to about 150 g/kg or a second carbon black having a DBP value in a range of about 65 to about 130 cc/100 gm and an Iodine Number in a range of about 25 to about 85 g/kg;
• wherein said method comprises (1) blending said elastomers and carbon black, exclusive of silica and of sulfur curative, in an internal rubber mixer in a first preparatory internal rubber mixing stage for a period of about one to about 10 minutes to a temperature in a range of about 150.degree. C. to about 180.degree. C., (2) blending said precipitated silica and silica coupling agent, exclusive of carbon black and of sulfur curative, in at least one internal rubber mixer in an additional, subsequent preparatory internal rubber mixing stage for a period of about one to about 10 minutes to a temperature of about 150.degree. C. to about 180.degree. C.;
• wherein said oil, if used, may be added either with the carbon black and/or with the silica, and (3) blending sulfur curative(s) with in an internal rubber mixer in a final internal rubber mixing stage for a period of about one to about 4 minutes to a temperature in a range of about 80.degree. C. to about 130.degree. C.;
• wherein said rubber composition is removed said internal rubber mixer at the conclusion of each mixing stage and cooled to a temperature below 40.degree. C.