And the 8.25x20 is about the same outside diameter as a 9R22.5.
Which is about as small as you'll find for modern 22.5 without going to low profile tires.
Although I have seen and owned some 8x22.5 tires and even a 7x22.5 tire, seriously doubt you find new ones in those sizes though.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-