Originally Posted by
John E
Is that a homebrew granny ring? Nice!
Originally Posted by
seypat
Is the inner ring a freewheel sprocket? Yea baby!
It's a SunTour Perfect 22T splined cog, the smallest with a multiple of five holes/slots (ten on this one) to make it simpler to fit this five-arm crank. A few bolts, nuts and washers and presto! In the ancient days before megarange gearing this was quite a thing. Built in '83.