A method for preparing a “predispersion” of carbon nanotubes in a wax or wax blend involving melt-mixing, cooling and grinding the blend, preferably multiple times. The wax predispersion may provide particularly improved dispersion of single-wall nanotubes in ethylene-α-olefin elastomer compositions, resulting in improved reinforcement from the SWCNT. The improved elastomer compositions may show simultaneous improvement in both modulus and in elongation at break. The inventive elastomer compositions may be formed into useful rubber articles.