You picked it up from our very own Tech Tip on wheels and tires for big trucks:
http://www.stovebolt.com/techtips/wheels/

I agree, for a work truck go 19.5, for a non working or infrequently used truck go the cheapest way, for a show truck go original.

Look for some used wheels first, they are out there.. Double check they will fit over the drums before buying, but
I think you'll be fine.

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
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-