The wheels that the 7.00 and 7.25 tires fit is a 6 inch rim, found on most 1-1/2 ton trucks. 9.00x20s will not work on 6 inch wheels because they're too wide and you can't get the outer bead and locking ring on. I do believe you can put an 8.00 on the 6 inch rim but thats the limit.
The 2-ton trucks have the wider 7 inch wheel which accepts 8.00, 8,25,& 8.50s best with 9.00s being the limit. I don't think you'd have to worry about the wider tire sidwalls rubbing, because as stated above, if they're too wide, they won't fit the rims.
kbcsw, you're absolutly right. Underinflated dual sets will rub each other, and left unchecked will cause tire failure.
Rezman
