Jaxon was indeed the manufacturer, they built 21" rims in various widths and styles for:
Chandler
Cleveland
Dort
Essex
Franklin
Velie
Pierce Arrow
Oldsmobile
Gardner
Jewett
Oakland
Chevrolet
Buick
If you take the rims off the wheels and post a picture of the latch holding the ends of the split rim together, I may be able to give a positive ID. Chevrolet is always the best guess as they made so many more cars than all the others.