Originally Posted by
Hondo6
A brief note: the scans there are nice, but they're not necessarily 100% complete. Specifically, the 1985 Touring catalog there appears to be missing the page that listed the 470 and 660S. I found that page in the version of the Trek catalog at the Retrobike site.
My frame, which I initially thought to be either a 1985 or 1986 400 - turned out to be a 1985 470.
Responding to your post, I am not familiar with the 660S, only the 660 which is a racing model one step below the 760 and is included in the racing catalog. The models/years/colors sheet does not show that 660S model either. I use serial numbers first and then model/years/colors (assuming original paint which on older Treks is pretty much the norm) to validate models and years. Relative to your 400, the model/years/colors sheet shows the 85 to be "blue with white or yellow decals, also scarlet" while the 470 would be black with red decals. Is one of those combinations your bike's colors and is the paint original? Below is the model/years/colors sheet from wayback machine...... have a look. Below that is the serial number sheet for 1985. Often a serial number for the early part of one year can actually be in the latter part of the prior year's list as production for an upcoming year often started before a current model year had actually ended. That would be an explanation if your serial number actually predates the 1985 list.
https://web.archive.org/web/20210512...l_numbers1.htm
https://web.archive.org/web/20210512...erialNos85.htm