Originally Posted by
xiaoman1
the one I listed in the post has that strange large black ring on it (why the difference?)
I'm thinking it must be a "MegaRangeŽ" freewheel.
The color difference is just marketing; calling attention to the extra-low gear the cog provides.
in your estimation, will the freewheel allow for smooth shifting. I do not know what freewheel was on there originally, any ideas what it might have been if I want to find an original one?
If it's an SIS compatible freewheel it should work fine. The modern production has the fancy tooth profiles and ramps that facilitate smooth shifting.