Good idea. Believe mine is 18 right now. Are 20 or 22 cogs easily available or do I have to find the entire assembly with the higher number to swap from?

And since you've opened this can o worms... I'm super intrigued by the 2 speed internal kick back hubs. I love old tech that works (and without a cable, etc). Do you have any experience with those? Was thinking of the yellow/red underdrive version but now that you mention changing the cog, could perhaps go overdrive and then just size up the rear cog (or reduce the front, I suppose). Unless those cogs can't be swapped like the SA 3-speed hub?

Anybody have experience riding the 2-speed internal as a daily driver?