A rubber composition with disperse phase particles containing poly(phenylene ether) can be formed by a method that includes melt blending an uncured rubber with a poly(phenylene ether) composition containing a poly(phenylene ether) and an oil to form an uncured rubber composition, then curing the uncured rubber composition. Before being blended with the rubber, the poly(phenylene ether) composition exhibits a glass transition temperature of about 40 to about 140° C., and during blending with the rubber, the oil component of poly(phenylene ether) composition migrates from the poly(phenylene ether) composition to the rubber, leaving a poly(phenylene ether)-containing disperse phase that gives rise to a second hysteresis peak temperature of about 160 to about 220° C. as measured by dynamic mechanical analysis of the cured rubber composition. Also described are the poly(phenylene ether) composition used in the method, a cured rubber composition formed by the method, and a tire containing the cured rubber composition.