Originally Posted by
irwin7638
Back in "the day" the smallest chainringd to fit a double crank was 42 tooth. Marc
This is simply not the case. Many racers of course used Campagnolo cranks when these came out, and the smallest chainring these would take was a 41 - though these are rare. Initially, the smallest was 44, until the bcd changed circa 1966. But Stronglight made a number of double cranks intended for racing that allowed for a 38 inside chainring; the Williams C1000 (a common choice in its day in the UK) took a 32 (the AB77 cotterless double could take a 26); and Magistroni made a number of doubles with 116 bcd that could take smaller inside chainrings. There are more examples. The big influencing factor on the relatively large size of inside chainrings on racing doubles until about 1962 or so was the commonality of half-step gearing (though some touring types would use a "half-step-plus-granny" setup).