After reading all of the horror stories of blowouts I ordered new Hankook tires for my MH. The old 670's were dated the 39th week of 2006. I had good experience with the Goodyears but from what I read...
The Hankooks have the same rating as the 670's they replaced which had a h rating which is a 16 ply rating which is the same as the Hankooks. The Michelins in that size have a j rating which is equal to an 18 ply rating. You are correct in some situations. In my case the Hankooks met the spec's of my coach:)