I had the same question with stems for my original '66 10 spokes. The top rubber ring on the stem will pull out above the wheel flange and lock in, just pull hard with soapy water. I too, tore a couple. I researched looking to find an oddball size stem that might have been around in the 60's, but no luck. I asked the same question as you on the "old" forum and never got an answer.