My 1951 Simplex PH-10 has a Simplex dropout with hanger for its Tour de France derailleur.
Joe Bender-Zanoni Great Notch, NJ
>When did rear derailleur hangers come into play. I have seen recently
>several bikes listed on ebay as being from the 50s with hangers and it
>does not sit well with me yet. Perhaps I just need more education.