most tires will only say maximum inflation pressure (44 psi for most passenger tires) just because the tire manuf. don't know what kind of vehicle
the tires are going on when they make them. A good rule of thumb for daily driving is 30-35psi.. And that's "cold pressure", when the tires have
sat for over 4 hours, and not driven for more than a mile.. And not to nitpick, but for $5 a tire at most places, Nitrogen is a joke. The molecules
are larger than the normal air, so they don't escape the pores in tires as quick, but regular air is appox 78% nitrogen anyway, so for the $20 not
spent on filling up tires with nitrogen, you can check them at a gas station yourself every month for 75 cents.