Rubber-free phenol-formaldehyde adhesive for bonding bright steel to rubber

In a tire containing reinforcing elements having a bright steel surface bonded to a vulcanized rubber by a rubber-free adhesive composition wherein the vulcanized rubber contains from a small but effective amount to improve adhesion to 30 phr of a phenolic resin adhesion promoter and from a small but effective amount to improve adhesion to 60 phr of silica, the improvement characterized by the adhesive comprising a cured phenolic resin formed by the reaction of a phenol and formaldehyde wherein the resin in its uncured state is selected from the class consisting of heat reactive phenolic resin, and heat reactive phenolic resin in combination with non-heat reactive phenolic resin, wherein the ratio of the phenol to formaldehyde in the resin is from 1:1 to 1:6.