Can someone please explain what these three numbers mean on the pedal crank housing? I believe this to be the pedal crank housing from a 1956 Spitfire Ladies Bike.

Serial reads M0D502 (small top left) The Serial reads 46772 (medium right) The large Serial reads 13 5 124

The Schwinn Serial reads M0D502 (hard to see but top left) The next number reads 46772 (medium right) The large number reads 13 5 124

One of my concerns is this... The Schwinn serial numbers that date the bike to the fall of 1954 or 1956, but I believe the Serial numbers for 54 and the 56 were located on the Left Rear Dropout - not located on the bottom bracket of the pedal crank housing. Why would this be?

Additionally what does the 46772 indicate? and what does the 13 5 124 indicate?

Thank you so much for all of your help!

  • Not much help but FWIW, the number on my early-1970's Schwinn Suburban is on the steering housing, two letters followed by six digits, in the range of HK549xxx. I presume that is the frame's serial number since it's both highly visible and the only number I can find. – keshlam Jun 28 '14 at 19:30
  • Again, dunno about this case, but other numbers on a piece often indicate model number, mold number if cast, and manufacture date. – keshlam Jun 28 '14 at 19:32

Are you sure that this is a Schwinn bicycle?

None of the numbers on the BB match the Schwinn serial number formats of the 1950s.

With all the numbers stamped on the BB it looks like Sears-Roebuck.

The 46772 might be the Sears catalog number.



This site attempts to decode the serial number, and if it is "M zero D five zero two" then the decoded result is

Congrats! Your bike is an original Chicago Schwinn.
Unfortunately the serial number you entered was used twice by Schwinn
meaning there are two possible dates for your bike...
Built: 08/13 to 08/23 of 1954 or... 
Built: 09/06 to 09/07 of 1956.



And more catalogues may be found at https://bikehistory.org/catalogs/ So you might browse through looking for something that matches your bike.


I am 100% that is a Murray bicycle. Mod stands for. Murray Ohio and the letter d is the year 1939 nice bike!

  • 2
    Can you provide any corroborating evidence? A link to something supporting your claim? – Criggie Nov 10 '18 at 1:11
  • An indicator that it's a Schwinn would be the welded on kickstand housing located on the chain stays. – P. Barney Nov 30 '19 at 1:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.