Originally Posted by bikingshearer

One small amendment here. First-gen Dura Ace cranks came in two flavors. The "touring" model had 52/39 tooth chainwheels with the mentioned outer chain guard (easily removed or reinstalled), while the "racing" model came with a 42 tooth small chainwheel and either a 52 or 53 large - I'm not sure which. The "racing" model did not have the chain guard. The bcd on both was 130, while Campy's was still 144 with the smallest possible chainring being a 41 - as a practical matter, though, 42 was the smallest you were likely to find.

Nostalgia note: Back in the mid-1970s, Talbot's in San Mateo CA had two stacks of chainrings in stock, one Campy and one Shimano, and you could walk in and buy pretty much any sized chainwheel from the respective minimum up to 54 or 55. Want a 46 Shimano or 43 Campy? They had it. Between that and the endless variety offered by SunTour freewheels, one could dial up damn near any gear combination one could think of (as long as it wasn't below a 39x28 or so for Shimano and a 42x28 for Campy). Good luck doing that now.

Beautiful Davidson. That is a great find.