Back in April, when I bought my Expedition, it came with a mix 'n match set of crappy rubber. I went to Firestone and I put a set of new Falken's on. Size was 265/60 17 but I don't remember the model. They were about $110 each installed. My experience is they provide a great ride and are very quiet, something that might or might not be important to you. Of course, they're all season and street oriented, so if you go off-road they might not be an option.