Yes they expensive. I will look for used ones. What would the wheel be the for the back dually wheels or do I simply flip the wheel around I guess? Same wheel? Sorry never had a dually yet and now discovering dually = spend more for 2 more tires and I guess 2 more wheels! I was a bit dim in not realizing that at the beginning of this journey. I'll have more money in wheels and new tires than anything else except for perhaps paint.
All six wheels on dually trucks are the same front to rear.
Many of us think the 19.5's look undernourished on 1-1/2 ton trucks, they just don't fill the wheel opening like the 20/22.5's do.
Check out Fred's thread here, he put 22.5's on his '56 Bus and used adaptors...
https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1354204/1.htmlMike B
