PAX is Michelin’s term for their version of a runflat tyre and has been developed with Pirelli and Goodyear.
PAX differs from other runflat systems available on the market in that the tyre is fitted to a specially-designed asymmetric rim that has a lager bead diameter inside to out. Inside the tyre / wheel assembly sits a support ring which supports the vehicle weight when the tyre is at zero pressure.
PAX tyre in normal pressure condition
PAX tyre in zero pressure condition
All pictures © Michelin Tyre plc
Not common at present in the UK, it is an OE option on such vehicles as Renault Scenic, Audi (A6, A8) and Bentley.
As with all run flat systems, PAX requires a tyre pressure monitoring system to be fitted to the vehicle.