Howard, I recently converted a bike for fixed gear riding. My first experience on one, last February, was a disaster. A couple buddies convinced me to do a fixed gear 200k with them. Big mistake, as the bike was not set up correctly and was geared too low. I bailed at 80 miles with sore knees and Brooks brass rivet marks branded on my you-know-what. But I learned a lot from that failure, and recently did a painless century on a Lenton frame. The differences: I rode a bmx free gear for a while and found out what ratio worked for me and my locale. It proved to be a 46/18 with 27 inch tires (about a 69 or 70?). Also, riding a single speed bike got me used to a single gear for hill climbing. I switched from toeclips to clipless -- a huge help when you're getting started. I switched from a B-17 narrow seat to a narrower swallow-style Lycett and lowered it slightly. The cranks are 170, my usual choice. I have two brakes on it, but really, the rear one is not necessary. To prevent another bailout, I built up a flip-flop Racelite hub, acquired from list member Pete Paine, with a fixed gear on one side and the bmx free gear on the other side. If necessary, I can turn the wheel around and coast home. Hope this helps.
Mike Dayton
Raleigh, NC