I just keep a beater bike that I use in the winter. The salt, sand and snow just wreaks havoc on chains, deraillers, casettes and bearings. I was also considering getting a Nexxus hub for a commuter bike but decided it'd be cheaper to just use something that I can abuse with almost no concern and then tear down and clean in the spring to be put away until next winter. Is there a specific reason you'd need to use a folding bike in the winter? Do you commute? If not, you can find a beater on craigs list pretty cheap. You can leave it locked up during the day outside with little worry about theft. My gf commutes daily on a beater Raliegh with no problems (crosses fingers). Just an option.