Rubber compounds are readily bonded to polyester reinforcing elements, particularly tire cords of polyester fibers, using a two-step dip process in which the first dip consists essentially of a low molecular weight polyallyl-glycidyl ether in aqueous media and the second dip consists essentially of an alkaline aqueous dispersion of a minor amount by weight of a mixture of a major amount by weight of a rubbery vinyl pyridine copolymer and a minor amount by weight of a heat reactable resinous composition. High H-adhesions are obtained with this process.