The tires that came on my Jeep are probably at least 16 years old, there is no DOT date imprint. I measured them, they are right around 30 inches. I'd like to go with a good reasonably priced 31 inch AT tire that will fit in my stock aluminum slot rims. I do have a small shackle lift so I think 31s would work well. My jeep is a 1974 Cj5. Recommendations?