I owned a Ford Fusion a few years ago. The Owners Handbook had the usual section on the tyre pressures for the car, normal and heavy load. To my surprise there was also included a “Comfort Ride” tyre pressure setting (not for heavy loads) that was 4 psi all round, below the normal pressure. The ride was noticeably better in Comfort Ride. I was not aware of anything special about the tyres that had been fitted by Ford. Is this option, in reality, open on any car (or perhaps any tyre) and if so would there be a size or profile of tyre above which it should not be adopted?