What bike serial numbers are - and where to find them. OldRoads.com - VVVintage Vintage Bicycles Schwinn Serial Numbers (Chicago Schwinns only) Everything on this web site is (c)2013 VVVintage Vintage Bicycles.

Hi, Josh- No 'I's (or 'O's) were ever used in Schwinn SNs, I don't think, due to their similarity to 1 and 0. All the Schwinn SNs with which I'm familiar are on the head tube (or head badge) or on the right drop out. So I'm thinking that what you're looking at is a part ID number. Look in the other spots and see if you find anything. If that is a Serial Number, it could be a Japanese-made frame--then the letter could be J or L, as Pastor Bob says. In that case, J=September and L=November, and the second digit would be the last digit of the year (in the 1970s, I presume).

That would make your bike 1977. Edit: According to a post on the Schwinn Forums by Scooper from 2006. I think that some bikes before the 1960s had SNs elsewhere, but I'm not for sure. Edit: 1951 and before, according to 'bunchobikes'--but weren't those mostly middleweight and heavyweight, with ashtabula crank? I have an early 80s Japanese Schwinn, and it's SN, if I recall, is on the dropout. Good quality, closeup pics of the frame (i.e. Pavement Wowee Zowee Sordid Sentinels Edition Rare. , lugs, dropouts, etc.) and of the original components, if any, would help a lot. OHHHH, the Greenville-built Schwinns.

Well, yes, of course they're different! Er, actually, if they are, I didn't know that. Oh, but of course, for me, Schwinn time ends in 1980, since the SLDB ends in 1980. So, what's the formula for post 1980 Schwinn SNs, and what year does it stop being reliable? At least as far as the Schwinn le tour models go, the serial numbers weren't on the bottom bracket shell until 1984; my 1983 has the serial number on the dropout, but the '84 has it on bb shell.