Our 2001 Adventurer came with 19.5" tires. Our 2013 Adventurer has 22.5" tires. The 2013 rides much better and the tires are lasting longer. Along with that there is far less road noise.
We currently have about 36,000 miles on our 2013 motorhome, and the tires still look like new. We replaced the tires on our 2001 at 47,000 miles. They probably should have been replaced a few thousand miles earlier.
As mentioned with the 22.5" tires you won't get a spare tire. We purchased a spare and leave it unmounted under the bed.