I'm not sure these were original on the Simplex RD. These two wheels came from the same Criterium; only the lower wheel still had plastic teeth. I suspect the sideways force of shifting caused the plastic teeth to wear off from the upper wheel's metal core. The Huret wheels are different - much narrower to fit between the chain sideplates.
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72+76 Super Course, 74 P-10+ 79 Tandem Paramounts, 84 Raleigh Alyeska, 84 Voyageur SP, 85 Miyata Sport 10 mixte and a queue