I have a pair of chrome 6-day track bikes that I bought used in Ohio in 1967. One of them had been in the basement of the local bike shop for a couple of years so they date to the early '60s at the latest. The story was that they were custom made by Cinelli for a Canadian 6-day team. Don't know if any of that is true but I'm skeptical of the Cinelli bit due to the method fo attaching the seat stays. The bikes are very similar but one has a more relaxed seat tube angle and a longer wheel base. That probably makes sense for 6-day bikes...one for sprints and one for cruising around the track when normal people are asleep. The only identification marks are the serial numbers, 058 and 059. Please have a look at the photos and let me know what you think.