The last of the possible locations is on the head tube, which is are on the very front of the bicycle (between the handlebars and the fork) on which the Schwinn logo badge is affixed.
Look below and to the left of the badge to find the serial number.
Visit the Schwinn Date Codes website--this is the "cheat sheet" for identifying Schwinn serial codes on the Internet, and it contains many other related resources and facts. The Date Codes website has a link for each of the three places mentioned in Step 1 where you might have found the serial number.
For example, if you found your code under the bottom bracket, click the link below the line on the website that says, "IF THE SERIAL NUMBERS ARE FOUND UNDER BOTTOM BRACKET." Match your serial number and find out the exact year, month and day your Schwinn was made.
The code is helpful in dating decks after 1904, the year it started, according to the Hochman Encyclopedia.
But, I have found evidence that the dating code was actually in use prior to 1904 which is why I have amended the chart to include 1900-1903 (highlighted in yellow, below).
From 1948 to 1982, Schwinn pioneered its own models of cruisers, touring bikes and three-speeds, fabricating their own frames and components in-house.For appraisal purposes, this date will be helpful in determining your bike's collector value, though it is not a definite rule.Generally, the value is determined by what those within the community of Schwinn collectors would pay for that specific model and year.Thinking of going cycling as a first date activity? Not only is it cheaper than more traditional first dates (popcorn, eh?), it also gives you a great insight as to whether your prospective life-partner will be able to keep up with your awesomeness, on or off the bike.