07-21-2020, 03:14 AM
So I tried to find the Simplex derailleur, but no luck; found similar ones though. I was curious if the "78" was indeed a date code; given the hub dates I would be inclined to think that it is; but there was no mention of other Simplex derailleurs having a date stamped into them. Knowing that the hubs are Normandy makes the dating easier since they go by week and year so "51 77" is the 51st week in 1977, December. Probably with that older '77 hub date it would indicate a 1978/79 model year bike. I didn't see a catalogue either year showing your model or variant, but they made them into 1985 at least.