Well, I see you're as stumped (or as busy) as I am! If you'll forgive my speculating a little on my own... Not Ford, GM or Chrysler. I've seen Hudson and Studebaker wheels from the mid-thirties and that's not the answer. I'm not familiar Nash, Graham or Franklin, though. Are any of you? It occured to me that maybe they could have been off of a light pick up, like an International, but I don't know if anyone would have used a 4.25" rim on a any truck...