Abstract: A method and apparatus for producing a tire such that the tire has a visible contrasting reference line consisting of a die line ridge produced coincidentally with the extrusion of the tread of the tire and a color contrasting ink applied to the peak surface of the die line ridge by a particularly described inking apparatus. The reference line so produced enables objective visual comparison of the position of the reference line relative to the position of the parting line visible in the cured tire as removed from the mold such that deviations of the reference line with respect to the parting line clearly indicate a tire having an objectionable dissymmetry with respect to its equatorial plane and such that the tire can be removed from the production stream. The reference line so produced and particularly the die line ridge have advantages over previously employed centerline tracking methods and apparatus.