Bicycle oddities and factory mistakes

[Monarkman]

Serial numbers seem to be one of the most common production oddities/errors found and it most likely started on the very first bikes that came with the hand stamped serial numbers.
The machine stamped serials started a whole different page on oddities or errors that were caused by both mechanical and human error. Many believe the serial numbers were stamped when the frame was built, and that may have been the case decades ago until the manufacturers realized it was more efficient to pre-stamp the numbers on the actual part before it was used in building a frame.

Pre-stamped serial located in the wrong location. The 1960's Tandems used electro forged dropouts to the chain and top seat stay and the middle stay was hand welded to the dropouts and those welds covered part of the serial numbers on numerous pieces.
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A 1970 Schwinn Twinn with a serial stamped on the dropout and one stamped on the head tube. This tandem was built with two pre-stamped components during the change of the serial number location in 1970.

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At the beginning of the January 1966 stampings there was either a mechanical issue or possibly someone failing to insert a stamping die in the stamping head. Someone didn't check the stamping dies in the machine so some were stamped with no year letter and some were stamped with no month letter. This is noted on the Anglefire serial list as recorded in error, but it was actually a stamping error.

1966 Varsity missing the year stamping die.
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Wow! Thank you for the post. Looks like a lot of quality control issues.

 

[Boatman]

Let’s see your bicycle oddities/factory mistakes. The stuff that you just don’t see because it is super uncommon, but is just plain cool. That factory worker that took a cat nap as a few frames went by, the one frame that missed the silver base coat etc. Think printing mistakes in currency, but on bikes. For example if @phantom could post up his upside down serial on his red Schwinn that’s what I’m talking about. I don’t have any to share but I want to see what you’ve all got.

I don't think that this was intended as a mistake, but it certainly was. Designed to keep the rider clean it ended up far too heavy and very few were made. There are believed to be only 3 examples left.

People always ask where the engine is and probably the best answer is "on the saddle"

 

[coasterbrakejunkie1969]

@MEKANIXFIX why a sad face on my post?

 

[MEKANIXFIX]

@MEKANIXFIX why a sad face on my post?

Hi just a little reaction, that could be sad to find that mystical number in the bike serial#

 

[Hastings]

Happy factory flaw-up friday everyone. Schwinn 20” girls early post war 16” brace arm radius stamped into 20” brace.

 

[10~18kustoms]

Early Dyno Cruiser with headbadge D on upside down.

 

[spoker]

incorrect date stamps,are confusuing somtinres,i collect gm muscle cars and mistamed numbers showup often,i also sold a 1955 og shwinn corvette with misstamped numbers,there normal ppl were stamping this stuff,there is bound to be mistakes,

 

[GTs58]

Here's another odd Schwinn serial stamping.
Not mine, owner Mr T. Martin

 

[DrRumack80]

The EF joints look close to the BB shell on that one.