Jarlaxle...those are most definitely not 11X22.5s...if you look closer you'll see the cast iron spoked hub, which in turn would be attached to the steering knuckle which in turn would be attached to a kingpin and straight axle...The rim is a 20" Dayton style single lock ring rim...and having been in that industry for enough time to know that the tires used in that config were 20" either a 9.00 or 10.00 tube type.
To the best of what I remember, to convert, a different knuckle would be required. And for that reason probably better to find a used axle assembly at a truck salvage dealer.
Driving the bus with those tires could be a very large problem.