Because of weight close to max GVWR, we decided to go a little upscale from the truly excellent tires like MS/2, Transforce, BFG, and get Bridgestone Duravis R250. These are a "highway" tread like Michelin XPS Rib. Our R250's were 7 years old and showed zero problem signs. Not in the tread, not in sidewalls. But we had two older Brigestone V-Steel tires, same size and approximate tread pattern. THESE turned out to be 10 YOA and and were developing cracks at the bases of the tread ribs, parallel to the ribs. Several on each tire. The spare was an OEM Firestone from 2002, never on the ground. Bottom Line: SEVEN NEW R250's. You don't want to have 100 miles to a tire shop and learn you had a 50-mile spare!