This may sound silly but some old farm tractors (Mccormick Deering) had a small wheel with cap around the edge. Not exactly what you are looking for but just wanted to let you know we are listening.

Good luck

Ken

1946 Chevrolet 2-Ton
In the Stovebolt Gallery
More pix of the '46 on Photobucket

1954 Chev 1/2-ton
3 Farmalls
4 John Deeres
1 Oliver
1955 DeSoto Fireflite

I'm pullin for ya. We're all in this together -- Red Green