Originally Posted by
stardognine
If you look around closely, on the serial number pages, there's a link to the production totals, for each model & each year. It's a spreadsheet thingie, that someone made up from Trek's data, in their journal. I think I said that right, but when you find it, you'll see that I'm at least mostly right. 😉 BTW, I looked around there again yesterday, and there was an '86 Trek 520 Cirrus, with fairly long chainstays, but no 620 Cirrus. Don't sweat it, I'm sure it was an honest mistake. I know I've had to read through that site several times, it's fairly confusing. 🤔
And hey, read that '86 brochure again, especially the introduction paragraphs, for each category (racing, touring, etc.) . It clearly states that all the steel frames assembled with the new robots, were brazed with silver rods. Obviously, not the aluminum & carbon frames, lol, but the steel ones, which were obviously made in much smaller numbers. 🙂
It's no mistake.
The leftover 1985 model year Trek 620s were sold as "620 Cirrus" models that weren't in catalogs. The 520 cirrus in 1986 had sidepulls and sub 43cm Chainstays. Do a quick search for "Trek 620 Cirrus" and you'll see what's clearly 85 model year 620s with a silver head tube similar to the 1986 paint scheme. You'll often see them as 1985 models because they're made and serialed in 85. The 1987 Trek 520 was back to touring form with cantis and 45.5cm chainstays.
Keep in mind, a model year's bike is also manufactured towards the end of the preceding year. On November 20, 1984 799 Trek 620s were serialized.