A process of preparing a rubber composition, the process comprising preparing a blend using, based on parts by weight per 100 parts by weight rubber (phr), where the term rubber excludes syndiotactic polybutadiene polymer: a first step which comprises forming an alloy comprising filamentary syndiotactic polybutadiene dispersed in a cis 1,4-polyisoprene rubber, the first step comprising: forming a blend of syndiotactic polybutadiene and cis 1,4-polyisoprene rubber comprising blending in an internal mixer: (a) 2 to 50 parts by weight syndiotactic polybutadiene polymer having a softening point in a range of from 180°C to 230°C and having at least 70 percent of its monomeric units in a syndiotactic 1,2-configuration, with (b) 98 to 50 parts by weight of cis 1,4-polyisoprene rubber; wherein the syndiotactic polybutadiene polymer and the cis 1,4-polyisoprene are blended in the internal rubber mixer rubber at a temperature of at least 10°C above the syndiotactic polybutadiene polymer softening point; continuing the mixing at sufficient shear mixing conditions and mixing temperature to form a dispersion of micro sized domains of the syndiotactic polybutadiene in the cis 1,4-polyisoprene rubber and to elongate at least a portion of these domains and then cooling the composite to from the alloy of filamentary syndiotactic polybutadiene dispersed in the cis 1,4-polyisoprene rubber, followed by a second step which comprises forming a rubber composition comprising blending up to a maximum temperature of 170°C: 100 phr of sulfur curable diene-based elastomers comprising cis 1,4-polyisoprene rubber, preferably the cis 1,4-polyisoprene rubber, and at least one additional diene-based elastomer; a sufficient quantity of the alloy to provide from 2 to 50 phr of the syndiotactic polybutadiene polymer with the diene-based elastomer(s), 0 to 150 phr of a reinforcing filler comprising: (a) silica, or (b) carbon black, or (c) a combination of silica and carbon black. a first step which comprises forming an alloy comprising filamentary syndiotactic polybutadiene dispersed in a cis 1,4-polyisoprene rubber, the first step comprising: forming a blend of syndiotactic polybutadiene and cis 1,4-polyisoprene rubber comprising blending in an internal mixer: (a) 2 to 50 parts by weight syndiotactic polybutadiene polymer having a softening point in a range of from 180°C to 230°C and having at least 70 percent of its monomeric units in a syndiotactic 1,2-configuration, with (b) 98 to 50 parts by weight of cis 1,4-polyisoprene rubber; wherein the syndiotactic polybutadiene polymer and the cis 1,4-polyisoprene are blended in the internal rubber mixer rubber at a temperature of at least 10°C above the syndiotactic polybutadiene polymer softening point; continuing the mixing at sufficient shear mixing conditions and mixing temperature to form a dispersion of micro sized domains of the syndiotactic polybutadiene in the cis 1,4-polyisoprene rubber and to elongate at least a portion of these domains and then cooling the composite to from the alloy of filamentary syndiotactic polybutadiene dispersed in the cis 1,4-polyisoprene rubber, followed by forming a blend of syndiotactic polybutadiene and cis 1,4-polyisoprene rubber comprising blending in an internal mixer: (a) 2 to 50 parts by weight syndiotactic polybutadiene polymer having a softening point in a range of from 180°C to 230°C and having at least 70 percent of its monomeric units in a syndiotactic 1,2-configuration, with (b) 98 to 50 parts by weight of cis 1,4-polyisoprene rubber; wherein the syndiotactic polybutadiene polymer and the cis 1,4-polyisoprene are blended in the internal rubber mixer rubber at a temperature of at least 10°C above the syndiotactic polybutadiene polymer softening point; (a) 2 to 50 parts by weight syndiotactic polybutadiene polymer having a softening point in a range of from 180°C to 230°C and having at least 70 percent of its monomeric units in a syndiotactic 1,2-configuration, with (b) 98 to 50 parts by weight of cis 1,4-polyisoprene rubber; continuing the mixing at sufficient shear mixing conditions and mixing temperature to form a dispersion of micro sized domains of the syndiotactic polybutadiene in the cis 1,4-polyisoprene rubber and to elongate at least a portion of these domains and then cooling the composite to from the alloy of filamentary syndiotactic polybutadiene dispersed in the cis 1,4-polyisoprene rubber, followed by a second step which comprises forming a rubber composition comprising blending up to a maximum temperature of 170°C: 100 phr of sulfur curable diene-based elastomers comprising cis 1,4-polyisoprene rubber, preferably the cis 1,4-polyisoprene rubber, and at least one additional diene-based elastomer; a sufficient quantity of the alloy to provide from 2 to 50 phr of the syndiotactic polybutadiene polymer with the diene-based elastomer(s), 0 to 150 phr of a reinforcing filler comprising: (a) silica, or (b) carbon black, or (c) a combination of silica and carbon black. 100 phr of sulfur curable diene-based elastomers comprising cis 1,4-polyisoprene rubber, preferably the cis 1,4-polyisoprene rubber, and at least one additional diene-based elastomer; a sufficient quantity of the alloy to provide from 2 to 50 phr of the syndiotactic polybutadiene polymer with the diene-based elastomer(s), 0 to 150 phr of a reinforcing filler comprising: (a) silica, or (b) carbon black, or (c) a combination of silica and carbon black. (a) silica, or (b) carbon black, or (c) a combination of silica and carbon black.