Abstract: A tube assembly for use in a process of vulcanizing a pre-cured tread onto a tire casing is disclosed. The tube assembly includes an elastomeric tubular wall having an inner periphery with a protective non-woven fabric layer covering a major portion thereof. The fabric layer includes a plurality of polyester cords extending in parallel relation in a single ply elastomeric matrix. Longitudinal edges of the fabric are covered by thin strips of elastomer bonded to the fabric layer and the tube wall. Superimposed fabric reinforcing swatches are bonded to the fabric layer around the valve stem. The tube assembly is resistant to being damaged prematurely by the rim which supports the tire casing in the tread vulcanization process.