275/80r22.5 TO 11R22.5
I have an Itasca coach with 275/80r22.5 tires. On my coach, I honestly think that extra inch of diameter of the 11r22.5 tire might be a problem. When dumping the suspension, there's not much clearance to the body work. Both sizes use an 8.25" rim.
After posting, I see you have 70 series tires. They are even shorter than my 80 series tires. I would stick with the OEM size. Also, the extra sidewall on the 11.00 might make your coach handle differently.
2005 Itasca Horizon 40FD