Hi Schocca, thank you for the great length you took to answer my question! I am surely in need of a guide as I look for a possible path for parts upgrade for my Espresso! Are both Tiagra and Sora version compatible with the frame? So far I'm a bit leaning to the Tiagra version, as I think I can source the parts easier, the only hard to get currently is the FD.
So for a bit background, I happen to own a Dahon Espresso myself, bought it over 10 years ago. For some reason, I stopped cycling and after years earlier this year, I decided to bring it to my local bike shop and restore it. I have been cycling around the town with it since.
So I notice that the stock parts on Dahon Espresso have become less common these days, like the bike is still using freewheels while nowadays the industry seems to have moved to freehubs. In case I need a part replacement, I figure might as well upgrade the bike. The road bike path would be good for me as I plan to ride the bike within the city (and carry some groceries along the way).
My Dahon Espresso - mostly still using stock parts except for the saddle, pedal, additional rack, and mudguards.