Some variations come into play with old wagon wheels. Condition, steel rims, diameter of the wheel, etc. I can't imagine an antique shop not interested in them. They are still used for wagon repair or yard ornaments. However, I come from the Midwest where they are still seen from time to time. In my area a nice wheel will usually bring $100 tops at auction. There should be dealers that would be interested but remember a dealer has to also make a profit. Selling on-line is difficult because of shipping. You'll have to broaden your search.
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best..............T im