(3%) Information Bulletin. Consumer Relation Department Schwinn Sales Inc.1856 North Kostner Ave, Chicago Ill. Bulletin Number 23: SCHWINN BICYCLE IDENTIFICATION NUMBERS*. Product serial numbers offer a precise method of identifying, registering and recovering stolen personal property.

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., 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. As far as '80's Schwinns having serial numbers that are reliable, I'm not sure many of them do, at least not the Greenville ones.

The Greenville-built Schwinns often have serial numbers starting with 'S' (which might indicate Greenville), then a letter representing month of manufacture, then a number representing year of manufacture. Such as the serial number starting with SG4 I mentioned above, which would seem to indicate Greenville, July, 1984.

But we've discussed a bunch of these Greenville-built Schwinns here, and there are inconsistencies. These should help some.

For a Schwinn published bulletin, this has a few errors: I. Serial number location: C. 1952 - 1971 numbers were stamped on the left fork end. This was moved in April of 1970. Frame design: C. Flash welding (butt welds on head and hanger projections) since 1958.

I think this has been around since 1949 (at least -- maybe I'm interpreting this wrong?). Parts innovation: F. Middleweights introduced in 1956. The Corvette was introduced in 1954 (for the '55 model year). Scooper's Dad is on the far left! There is also the anomoly with Bridgestone using place holders for months prior to the model year (for example, November and December of 1982 for the '83 model year would be X3 and Y3, then January would be A3), but this probably started after this Bulletin was published (don't hold me to those years). I think some Panasonic (Japan) built Schwinns also had serials on the headtube (Voyageurs), but that probably came later as well.

The '80s dating was crazy! We can't even get a straight answer out of Richard Schwinn. Norman Guitar Serial Number Search there. So, are post 1984 Schwinn's ID'd by: 1st letter = month, 1st number = year (ie 1977 or 87 if the number is 7) and the remaining numbers are just the production run? For what it's worth, I have a 87 Schwinn Circuit Headbadge#0257 and SN#I637223 Someone on this thread has an unknown bike w/Headbadge#0267 and SN#I637212 This means that the badges of said user and mine were stamped on consecutive days - mine being a day older My Circuit also has the '8' stamped on the bottom bracket. I wouldn't want to infer too much as I don't know about the production process but seems like someone with that kind of knowledge could perhaps look at how close the Headbadge and SN numbers are on these two bikes and form some kind of hypothesis about ID'ing via SN. Of course all this out the window if I missed the elephant in the room about later model Schwinn ID methods that exist somewhere out there now - in which case - please forgive. The serial number format depends on who built the bicycle.

I'm not an authority on Schwinn but I'm pretty good with Asian serial number formats and that format is consistent with Bridgestone, who were a known source for Schwinn. The first character in a Bridgestone S/N was a month, but then it changed to fortnight, sometime in the late 1980s.

So, it could represent the 9th fortnight or September of a year ending with '6'. Based on the head badge code, September is more likely. While some manufacturers do code model identification and further stratification into the serial number, it is quite rare to go beyond month or fortnight.

When looking at the sequential frame number, two numbers that are fairly close to each other may be from the same batch but you really don't know when one batch ends and another starts. Once you have a manufacturer, year and month or fortnight, you are typically better off identifying the decade and model via frame features and/or components. Mcdsp Emerald Pack Torrent Mac Torrent.