Improved implement for demounting and mounting self-supporting tyres of the system pax type and the like

Improved implement for demounting and mounting those self-supporting tyres which comprise a tyre with beads of different diameters and a support ring to be inserted into the well in the wheel rim, this latter being provided with seats for receiving the different-diameter beads of the tyre, the implement comprising a wheel rim support device to be associated with the self-centering unit of a tyre removal machine, and a tool secured to said support device and arranged to interact with the tyre bead.