I finally got around to tightening the headset on "Totally 80's." It's been loosening on its own as I ride and I've been hand tightening on the fly. I don't have the perfect size wrench for it - I think maybe it's 1-1/8 or 1-1/4. So I use the adjustable wrench which can mark the nut. I used to use a rag to protect the nut. This time I used a piece of old inner tube and it worked much better.