I was on the way to town this morning, and when I downshifted to 1st, I heard this terrible crunching noise and my rear wheel locked up. No fault of the derailleur, mind you, just my poor memory to replace that derailleur wheel bolt when I temporized a fix, or, to not shift into 1st before I did so.

Anyway, I'd like to stick with a better version of what would be period correct for this '75 Peugeot PX-50, does the derailleur on a PX-10 work well? Any recommendations? (Anything other that a plastic-bodied one, that is.)