A tire molding matrix comprising a plurality of projections on the tread molding surface of the matrix, the projections being for molding a first, radially outer and a second radially inner, pattern in the tread of the tire incorporating at least one main drainage groove, the configuration of the projections changing distinctively at a predetermined level which is substantially parallel to the surface of the matrix for molding the tread ground-contacting surface of the tire and which is situated at a depth which is a predetermined amount less than the depth of the projection for molding the main drainage groove, the second pattern comprising a wholly radial extension of only a part of the first pattern.