Originally Posted by
rccardr
From 86 to 92 Cannondale used two different serial systems. Your frame appears to have used the second system:
Single digit spacing (0= 120 or 130, 5= 135, 6= 126)
Double digit frame size in mm for racing frames, inches for touring frames
Four digit date code
Four digit sequence number
My guess is that you have either misread the first digit or it is incorrectly stamped. Measure the rear dropout spacing. The rest then follows:
60 cm frame
Built 09/88
44th frame built that day.
Which makes it an 88 or possibly very early 89 model year frame.
Thank you for the response! Interesting, the 8 is very clearly printed there. How common is it that they incorrectly stamped it?
I can't post proper links here because I haven't posted enough, if you just take the spaces out this a link to a pic of the serial number: h t t p s://imgur.com/oHb7LaG