Changing wheel size

Regarding our post on tire blowout, we have a 2006 --2619 which from what I can determine is the last year they installed 14 inch wheels. When I was relating my problems finding a tire to a fellow owner on the road he said he wondered if the wheel size can be changed, I guess I am wondering as well, has anyone done this and does anyone know what the feedback from the factory is about this kind of modification? I now have two new tires, but if the safety of the rig will be improved with the larger wheels I would make the change. After I had problems locating tires I looked at northern tool and they had them available as well . They also sell the identical wheels to what is installed on tm.