What's the difference between a 265/75/15 and a 31x10.5/15? I know there is a slight difference in size, but what about composition? Will the 265 not hold up as well on the trail? I do mostly on road driving with some trails thrown in when I can. I'm looking for an AT tire and have my eye on Falken High Country and Cooper Discoverer AT3...I was looking at Duratracs and AT KO's and then I realized that money doesn't grow on trees :/ although I'm open for suggestions regarding good values. Any help would be appreciated here.