I am kinda liking the General Grabber AT-2 in a 255/60R18.

A little smaller than what I have now, but that's alright. (10.03" wide vs. 10.4" wide). The only thing I noticed was that the 255/60R18 was "NOT RATED FOR SEVERE SNOW", but the 265/70R18 are rated for severe snow.

That kind of makes sense because they would have a wider contact with the ground, but when you look at the 16" sizes, it gets confusing.

255/65R16 NOT RATED FOR SEVERE SNOW
255/70R16 is Rated for severe snow

Both of those have the same width, just larger rim to tire size.

I guess my question is, is there anything else that is different about the 255/60R18, other than its not as wide? Seems like it was just outside the range of the severe snow rating.