I have two problems that hopefully someone can help me with. I bought a used coleman westlake pu last year and it had decent tires on it. I traveled from Dallas Texas to Destin Florida earlier this summer and had significant tire wear. The tires are wearing on the inside and outside edges. Definite cupping on the tire edges. I was running the tires at 35psi, but i saw last night that it calls for 60 psi at the max load. So i think i have ruined a good set of tires by having them under inflated. Any thoughts? The tires are Duro XL ST185/80D-13 Load Range D I have read the post on this forum and realized that they are not the easiest tire to find replacements for. I have looked at Northern, Etrailer, Eastmarine, Richard Tire, and a few more with no success. The problem is finding the Load Range D. I have found some ST175/80D-13 Load Range D, and I have found the ST185/80D in a Load Range C, but I think I want the original tire size back on it. I know this question has been beat to death, but any additional thoughts?