Shimano Crane was mid '70s. And there was the Campagnolo boat anchor (I intentionally forget its name) was available in the late '60s, IIRC. FWIIW, I have had an Eco Duopar shift a 50-42-31X16-20-25-30-34-38 and it could handle 50X38 and 31X16.
__________________
Bob
Enjoying the GA coast all year long!
Thanks for visiting my website:
www.freewheelspa.com