Originally Posted by
Retro Grouch
How old is the bike?
Back in the days of Delrin bodied Simplex Derailleurs we used to get that a lot. The period appropriate solution would be a Suntour VGT derailleur.
I have original 6 speed Sachs-Huret Rival rear derailleur paired with Sachs downtube friction shifters on 13-24 freewheel on 1985 Peugeot PGN-10.