I replaced the G614 16" G rated tires on my 15,000 Lbs 5'er with 17.5" Michelin J rated tires. The four J rated tires will carry 19,000 Lbs total and the G614 would carry 15,000 Lbs. I was having some blowout problems with the lighter tires. The original G614 s were barely adequet. Now I have a cushion.
I believe in putting tires on the rig to carry 125% of the rig's total weight. Forget the weight on the pin and you have a nice conservative setup as far as tires are concerned.
Ralph & Snickers
2006 3500 Chevy Dually - 8.1 - Allison
2006 30' New Horizon - Solar