Oh theory or whatever, I am not gonna fill Nitrogen anymore. For December Vacation I filled nitrogen in my punto. Had a not so good experience. On the highways It was very good. Once I started driving in the city roads, the ride was very bumpy. The pressure was 30 but still very bumpy. Then reduced to 28 but still the ride was bumpy. Finally decided to take out all nitrogen and fill with Air. Only then the ride came back to normal. I was not at all interested to fill nitrogen for a long time (even in santro days) but this time I wanted to see what change it brings, ust for the sake of trying it once. But that turned out to be a bitter experience.