Abstract: A process for producing a tire having an expandable chamber utilized for extending and retracting studs provided in the periphery of the tire. In one embodiment, a non-stick film is strategically positioned between the casing and the tread prior to curing the tread onto the casing. The interface at either side of the film forms the sides of an expandable chamber. The tread side of the chamber is inset and studs are affixed thereto. Expansion of the chamber extends the studs out of the inset and into engagement with a road surface. Alternative processes provide a channel in the tread and the expansion chamber formed in the channel.

Abstract: A tire as provided with a circumferential portion for contacting a road surface. Edge segments thereof include studs and an inflatable chamber at the edge segment is inflated and deflated to extend and withdraw the edge segments for engagement and disengagement with the road surface.