Well, yes, of course they're different!Įr, actually, if they are, I didn't know that. Good quality, closeup pics of the frame (i.e., lugs, dropouts, etc.) and of the original components, if any, would help a lot. I have an early 80s Japanese Schwinn, and it's SN, if I recall, is on the dropout. Edit: 1951 and before, according to 'bunchobikes'-but weren't those mostly middleweight and heavyweight, with ashtabula crank? I think that some bikes before the 1960s had SNs elsewhere, but I'm not for sure. Edit: According to a post on the Schwinn Forums by Scooper from 2006. 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). 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. Look in the other spots and see if you find anything.

So I'm thinking that what you're looking at is a part ID number. No 'I's (or 'O's) were ever used in Schwinn SNs, I don't think, due to their similarity to 1 and 0.Īll the Schwinn SNs with which I'm familiar are on the head tube (or head badge) or on the right drop out.

Schwinn id numbers