Originally Posted by pinnah

This just kills me.

As another data point, I paid over $250 on eBay for my 1979 510 frame. Now, the frame was made with the slightley stiffer 022 tubing, which is nice to have in my 64cm size and the frame was in great shape. There was at least one other serious bidder too. It was worth every penny for me.

I owned a 600 series bike for nearly a decade and rode it cross country in the 80s. They were lovely bikes with a fantastic geometry. In terms of production, they are a tick lower on the scale that the older Treks or the 700 series. In general, the 600 series bikes used japanese built pre-assembled rear triangles made from Mangalloy which were joined to 531 main tubes in Madison. The early Treks and the 700 series bikes in the mid 80 (which were 531 or Columbus through out) were assembled entirely in Madison.

One of the really cool things about the 600 series bikes is the front end geometry. They used a HA = 73 and FO = 5.5 which produces a very low trail. Very much in line with the old French style. IMO, this produces a ride that can not be matched. Velo Orange has just brought out a custom frame with similar geometry for around $1500. If I were wanting to get top dollar for a 600, I would target those folks interested in low trail bikes.