Originally Posted by
ncrnelson
I think it would be later than 83-85 as bradtx says. In 83 they only offered the st500 and I think through 85 only offered the st400 st500, neither of which had tight racing geometry like yours. I'd guess yours is between 86 and 89, I believe in 90 they switched to the cantilevered rear dropout criterium frames. Check the catalogs on vintageCannondale.com, maybe you can find a match.
Got out the magnifying glass and the serial # is either 88 1094 or BB 1094. If its BB, then that would be 84, but none of the frames in the 84 catalog look like a match. The 85 SR500 looks like it might be a match, but 86 and beyond, I can't see the underside bottle mounts in the catalog photos. Their frames looked very similar from year to year. The only parts that came with the frame were a 105 FD and a no
name chrome headset. Looks like the 105 wasn't used until 88, so its probably not O.E.
Guess I'll settle on mid-80's SR 500. Thanks for the replies
Edit: Also the location of the serial # on the bottom bracket places it in the early to mid 80's. After 85 the serial # was on the seat or chain stays.