I have a NWT too, and had the same problem. Solution: replace your headset with a Chris King. This is a common discussion on the BikeFriday forum, and several people have confirmed that their headsets stopped getting loose once they switched to the CK.
I can't figure out why Bike Friday doesn't make this a standard option. Ok perhaps they make a tad less on each bike they sell, but i've heard more than once about people who say they won't buy a BF because of the 'headset problem'.
Last edited by bokes; 12-13-06 at 01:50 AM.