I have 275/70R18 BFG AT KO2s on my Ram but that's the stock size that came on them. I considered going a little bigger but I didn't want to mess around with a different size on my spare. You would give up a few hundred lbs of carrying capacity with your stock size, though, so it's a tradeoff.
As far as the tires themselves go I love the way the BFGs have performed so far. They're a good heavy tire with really good all around manners. I haven't tried them on snow yet but I've had the same tire on other vehicles in the past and they've performed well on winter roads so I expect these to as well. The mountain snowflake symbol is very handy where I live in the intermountain west with some of the traction/chain requirements we run into sometimes during the winters.
As an aside I think you can improve the aesthetics considerably by going to an aftermarket rim with less offset - the stock offset on both Ford and Ram HD trucks make them look a bit pigeon toed, imo. Just be sure the weight capacity doesn't have a lower limit than the tires.
They aren't on your list but I'm a big Cooper fan too so check out the ST Maxx also. If I hadn't found a good sale on the BFGs I very well may have gone with the Coopers.
2015 Cummins Ram 4wd CC/SB
