A rubber formulation with good wet traction properties includes one or more elastomers and at least two types of particulate filler materials including at least one of which has a relatively high free surface energy in water (i.e., a supplemental filler). The formulation containing the supplemental filler(s) can provide a vulcanizate that has a British pendulum (skid) number that is at least .about.5% greater than that of a vulcanizate made from an essentially identical formulation that does not contain the supplemental filler(s). Also provided is a method for providing such a formulation which involves identifying one or more supplemental fillers having relatively high free surface energies in water, replacing at least 15% (by wt.) of one or more of the conventional particulate fillers in the formulation with an approximately equivalent volume of supplemental filler particles, and providing the modified formulation.