Gator Boat Trailer What Difference Would These Tires Make?

What difference would these tires make? - gator boat trailer

I have a 2002 Toyota 4Runner. My tires (Michelin LTX M / S) have done 71k miles and very good. When I get new tires at Costco told me they were not tired, series and did not give me the same tires (30x9.50 R15). You want the size recommended by the manufacturer, the size (225/75 R15) reduce to. I never realized that I had the standard tires. I ride urban, almost completely normal, although I take my boat on the weekends. The only off-road I do is when I go to a football match Gator skip a sidewalk or two parking spaces. I watched two wheels side by side and there is a difference of a few centimeters. I want to Costco / proposed, by the tire manufacturer or stay with what I have. I always Rief and there are many places to install my standard tire is simply not cost more money.