Abstract: A tire having a layer of uncured rubber in its tread portion is fitted to a hub and an annular protective chain is placed over the uncured rubber. The tire is inflated and the protective chain is tensioned by chains connected to the lateral edges of the chain and extending radially inwardly to the axis of and axially away from the central plane of the tire by means of a telescopic jack aligned with the axis of the tire. The tire is vulcanised by sealably enclosing it in a cover, venting the space between the cover and tire, and curing the rubber in an autoclave in which the tire is a loose fit.

Abstract: A tire chain comprising tread links formed with a perforation and connectors that are loops threaded through the perforations in three or more tread links interconnecting the tread links to form a network of closed figures. The connectors are loops of a carbon steel rod with the ends of the loops lapping each other and being welded together along the length of their adjacent surfaces. The tread links and connectors are of different carbon steels whereby after heat treating each is hardened throughout its thickness with the tread links having a surface hardness in the range 46 to 54 Rockwell C and the connectors having a core hardness in the range 15 to 35 Rockwell C.