Joe:
The Michelin site is fairly user hostile. The chart is a download, and you get to it by:
www.truckus.webmichelin.com
when the site comes up and it takes awhile to completely load, go to the banner on the left side go to: information
Bulletins
new tires
technical bulletins
and then scroll down to rv tires air pressure etc.
Lots of good information on their site, they just don't make it easy to get to.
Hope this helps
Chuck