[rzrbckr]

Originally Posted by CWtheMan

The ply rating is a reference. The official load rating for all ST and LT tires is the load range letter system.

6 Ply Rating = LR C 50 PSI
8 Ply Rating = LR D 65 PSI
10 Ply Rating = LR E 80 PSI
12 Ply Rating = LR F 95 PSI
14 Ply Rating = LR G 110 PSI
16 Ply Rating = LR H 125 PSI
18 Ply Rating = LR J 125 PSI

They put the ply rating on tire sidewalls because the DOD wants it there. They also put the actual number of plys there.

Each Load Range has a standardized inflation for the tires maximum load capacity, see above.

Here are some sidewall pictures.

http://www.irv2.com/photopost/showfull.php?photo=32259
http://www.irv2.com/photopost/showfull.php?photo=27064
http://www.irv2.com/photopost/showfull.php?photo=29711
http://www.irv2.com/photopost/showfull.php?photo=29709

CW, did I mess something up?