Blur911,
From my perspective there isn't a "lowest allowable pressure", only a "specified pressure". I take this position based on the idea that if a lower pressure were used, the tire is by definition overloaded if something is put in the bed of the truck even once - and that makes it a safety issue.
Titanium48,
These load tables are in books that are published every year by the standards organizations listed. While these are non-profit organizations, they do have expenses and the only method they have to recover those expenses is to sell the books. BTW, the books are on the order of US$100 each.
But occassionally you will find excerpts on the web. I forget where I saw them.
