I suspect the sharp tooth profiles are from wear. In the US, at least, it has been fashionable to use 52 or53 T large chainrings and 42T small rings on doubles. So NOS rings between 43 and 51T are sometimes available just because thet did not sell when new.
Regards,
Jerry Moos Big Spring, TX
Richard Robinson <vintagespoke@earthlink.net> wrote: Here is a question for the French experts out there.
I was able to buy a handful of NOS Stronglight chainrings today. I mostly found rings for the Mod. 99 cranks, but I also found a few rings for a 49d. The question I have is concerning the tooth profile. I noticed two distinct differences among the tooth profile of various rings, namely between the mod. 99 rings. Several rings have a very sharp tooth profile, almost coming to a point while other rings, with the same number of teeth, are more rounded, similar to a NOS campy ring. Even on the NOS Mod. 99 crank I purchased the 50T ring is sharp while the 45T ring is rounded. Is there a reason for this? If the sharp teeth were not uniform I would guess they were worn down from use and not NOS. Does the tooth profile indicate vintage?
Additionally, when purchasing vintage chain rings (Stronglight, TA, Campy), are rings with a cretin number of teeth rarer than others. For example, is a 50T ring harder to find these days rather than a 52T, or perhaps a 45T vs. 47T? I'm sure this is all based gear ratios, half and full step gearing etc.
Regards, Rich Robinson
Jacksonville NC