Another thing to keep in mind when playing with tire pressures is knowing
WHY you might want to add or delete air pressure.
One of the things to know is what is your rim width? What size tire should be run on this rim? How fast might you go? Etc...
As ronnie posted above, his tire diameter grows at speed. This in turn well pull the tire inward at the bead. If your rim is on the wide side, lets say 7", and the tire co. recommends a rim width between 6" & 7" you
MIGHT want to add air pressure to help keep the tire bead seated. This varies greatly depending on tire type, recommended rim widths, tire diameter vs. rim diameter, maximum speed run, vehicle weight, Etc.....
This is posted as food for thought. I feel know one knows your combination better than you, so you you need to try to understand as best you can
WHY you might want to change anything on your vehicle for better performance.
Good Luck on you project