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...
I have 22s on my suburban and had 19.5 on my gasser. When the time comes I will be getting 22.5 for the motor home. I think you will be happy. Might just be a little uncomfortable sitting on a fatter wallet.