By early 1959, serial number 949 had been reached, necessitating a new system.
The “New” System This system was used from Spring of 1959 to the end of 1965.
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.
For appraisal purposes, this date will be helpful in determining your bike's collector value, though it is not a definite rule.
It consisted of six components: Paramount Tandem Serial Numbers Paramount started building tandems in 1969.
Prior to this time, only special team tandems (like Olympic bikes) were made.
The first possible location is on the underside of the bottom bracket.
Sheldon Brown's Bicycle Glossary defines the bottom bracket as "the part of the frame around which the pedal cranks revolve." Turn the bike upside down to view it better.
The second possible location of the serial number is on the left rear dropout--the "fork end that allows the rear wheel to be removed without derailing the chain first," according to Brown's Glossary.
From 1948 to 1982, Schwinn pioneered its own models of cruisers, touring bikes and three-speeds, fabricating their own frames and components in-house.
After the "Bicycle Boom" of the 1970s, however, Schwinn's proprietary frame-building technology and heavier bikes became less economically viable in an increasingly weight-obsessed industry--resulting in millions of unique vintage and antique bikes that can be identified by their serial numbers.