Tires: tire pressures, jeep liberty, tire place

Question
Hello, I have a 05 Jeep Liberty 4X4. I went from P225/75R16 (Goodyear) to LT225/75R16 (Firestone). The tire pressure on the door says 33psi front and rear for "P". The tire place put 40psi front and rear. Is this pressure to little or to much? Does Firestone have a chart or formula for the tire size and loads? Do you need more info?

Answer
Doug,

No, I don't need more info.

40 psi in an LT metric tire gives the same load carrying capacity as the P metrics at 33 psi.

These load / inflation relationships are defined by tire standardizing organizations - in the US, it's The Tire and and Rim Association.  Since these organizations don't generate any revenue by selling a product, they "sell" their standards - which are copyrighted, which means they can't be published in the internet - you have to buy the book - $60.00!!