Schwinn Bike Serial Numbers
Schwinn Lightweight Data Book (Serial Numbers) Serial Numbers Chicago built Schwinn Serial Numbers for the years 1960 - 1969 are found on the left rear axle-hanger or fork-end on the frame; for the years 1970 - 1979 (Chicago built) they are on the headtube of the frame where the fork enters from the bottom (actually, this begins in April of 1970). The Chicago Serial Numbers consist of a letter representing the month of manufacture, a number indicating the last digit of the year (1960 - 1964; 0=1960, 1=1961, etc.) or a letter indicating the year(1965 - 1979; A=1965, B=1966, etc.), followed by a sequential series of five or six digits (e.g. A367584 or CB77584). If letters were used for date codes, they skipped the letters 'I' and 'O' as they looked too much like numbers. Note: This scheme is for all Chicago built non-Paramount models excluding 1962-1963 Superiors, 1964-1969 Super Sports and 1968 S/S Tourers (whose Serial Numbers are located on the left rear axle hanger and consist of a single letter code for the month [again, skip 'I' and 'O'], the last digit of the year and a 3-digit sequential build number -- e.g. 'K6018' is the 18th frame built in October of 1966).
I have an older schwinn roadbike frame that looks like its from the 70's or maybe the 80's. The serial number is on the bottom of the bottom bracket sideways. I checked schwinn serial number websites and apparently my bike frame doesn't exist because it starts with an I. My serial number is I702756.
The 1970 Super Sports with Huret dropouts seem to have used a two digit year ('C70204' -- March, 1970, 204th frame). The 1979 Chicago built Le Tour and Super Le Tour models had their Serial Numbers on the left rear axle hanger and began with an 'S', followed by the standard letter/number scheme. Bicycles from Japan will have Serial Numbers located on the left, rear axle hanger, on the bottom bracket shell or on the lower section of the headlug. The number will have a production month letter in either the first or second position and a production year number in the other (first or second) position. Free Download Iscii Devanagari Font. Examples: J677123 = September, 1976.
For some Japanese built Schwinns the headbadge will have a 4-digit stamping that represents the assembly date and consists of the ordinal day and the last digit of the year (2456 decodes to the 245th day of 1976 or 1986 -- use decals and components to determine the decade). The ordinal dating was adopted for Schwinn's domestic production in 1976. Some Japanese bikes may have an 'X' in the month position of the frame serial number. This was used to keep the physical year of production, for example 'X9' -- December of 1979, with the model year of the remainder of the production for that model -- 1980. This could also work for January back to a previous year. Some Taiwanese (built by Giant) Schwinns have a date code (on the right rear axle hanger or on the bottom bracket shell) in the format 'Gmmyy'.
The letter 'G' followed by a two-digit month code (01 = January etc.) and two more digits for the production year (80 = 1980 etc.). An example would be 'G0680' and equates to 'Giant, June, 1980'. Japanese built LeTour (and Super LeTour) numbers (1978) include the letter 'S' with a letter for the month of production and a single digit for the year of production (8 = 1978). Example: SC84652 decodes to March, 1978. For Paramount serial number information go to site.
1946 series Hxxxxx Ixxxxx Jxxxxx A0xxxx (small type face) Bxxxxx Cxxxxx (low number) Cxxxxx is probably a cusp number between 46 and 47. More on the 47 side. 1947 series Cxxxxx/Dxxxxx 1948 series Dxxxxx ect.
Identifying features: Skinny drop outs (1946) Razor edge fenders Shortie rear fender(early 1946 rare) light cover has deep rear screw hole Raised or de bossed style AS clamp(rare) Non scripted light lens Tapered pencil kick stand Canti frames have more of a hump to the top tube. (Early) Straight bars ie 'fat bars' have same dia bottom tubing. (This feature also was found on later years and is not solely indicative of a 1946) Rack clamp is a one piece flat band aid shaped plate. Rear top stay fender bracket is sometimes tubular on early frames. (I've only seen this on dx models). Courtois Flugel Horn Serial Numbers.
My 46 rear fender stay mount is taller and more boxy then late 40s 50s style. Early 46 tanks have been seen with tapped brackets ie left over snap style prewar tanks. Big outtie delta horn button and tank hole (prewar size). Chain guard front frame mount tab is thinner with bigger hole. Grips will be oval with one tail coming off N without double back crossover(late prewar style) Rear chevron will be shorter on 46.
Drop center rims or sometimes Lobdell flat profile rims. 1946 bikes have been found with 1941 stamped dogleg cranks skinny truss rods. Springer pivot bolt rumored to be chrome on early 46? Pivot clip was prewar style half clip.(early) Springer fenders sported diamond and tombstone reinforcement tabs Granted stuff got replaced or got carried over ie pencil stand. Note; (A) serial started again in 51 but in regular larger print.
What I have gathered doing research and asking experts is that the I J and K serials would have been left over prewar BB shells and or frames that had already been stamped prior. A being the first true postwar serial.
Hope this helps. Pm me if you have any further questions or would like to add something to the list. Click to expand.Yes and no. The first year that I see any recordings for the Tandem is 1949.
01/19 ------------------ T001000 ----- T001217 -(TDM) The Tandem's SN always started with the T00 during the years the T&C was available and the number was stamped on the rear bottom bracket. I believe after the T&C was discontinued the numbers went to the standard SN recordings and were then stamped on the left rear dropout, and this was sometime in the early 60's. The last entry for the Tandems that I can see was ------------------ T002663 ----- T003035 -(TDM).
I believe the original source for the Schwinn serial number information listed in the OP is here: From there it links to these pages: Note on the original pages where it states 'Copy and print this info at will, it`s FREE. BUT If You Steal The HTML And Post It On A Web Page In ANY Format, It Is Illegal' In that case it appears that the info in the OP's links was reposted without authorization or credit. I would only trust the information from the original source, as copies (especially unauthorized ones) can introduce errors. For example the it states: 'NUMBERS ARE NOW LOCATED ON THE LOWER LEFT OF THE HEADTUBE (By The Schwinn Badge On The Front OF The Frame)', whereas on the it states 'Serial #'s are now on the lower left of the headtube, by the Schinn badge on fromt of the frame'. Click to expand.Schwinn head tubes were fabricated from a flat piece of stock when the fillet brazed frames were no longer and EF came into play. That piece of flat steel for the head tube went thru many stampings, then rolled and then welded together. Here's the deal on the upside down SN.
The serial numbers were stamped by an automatic stamping machine and the head tube plate was stamped with a serial number prior to any rolling or welding. Some worker had the head tube plate upside down when he stamped the SN. I've seen a few of these along with a double stamping of the SN. One on the left top upside down and then a different SN stamping on the right bottom in the correct spot. Schwinn quit stamping the SN's when the frame was built when they quit stamping the numbers by hand. All auto stamped SN's were stamped on the component prior to any welding, building of the frame etc.