These wheels pop off pretty easily there are two threaded holes under the horn ring for this purpose. They are 5/16" I believe, blow them out with some air add a couple drops of lubricant and a small puller will have it right off. If you elect to pop it with your knees or a dead blow hammer put the nut back on so you don't lose teeth. You could source any wheel from 1947-59 I believe as a back-up they should all be splined the same.