Originally Posted by
Ronno6
Very interesting bike indeed........
The downtube is spec'd at 44.4mm, or roughly 1 3/4".
Cannondale began using 1 3/4" in '86, up from the original 1 1/2" for '83 to '85.
Yours looks to me to be the smaller size, but measurement will tell the tale.
Interesting locations for derailleur cable guides and housing stops.
I was told by a Cannondale rep back in '86 that the correct (official) way to measure their
frame is center of crank, up seat tube to a point 1cm above the top of the top tube.
This was due to the top headset race and the seatpost clamp being above the TT, hence
effectively making the frame 1cm larger than previous conventions.
Anxiously awaiting future info.
Thanks. DT (and TT) are 1.5".
I should have re-read your post about sizing prior to posting my measurements above - BB center to 1cm above TOP of top tube (rather than above the center of the top tube as above) should measure out to a 61cm - still not a stock size from the early years (TT length measured CTC also doesn't match the catalogs...57.5cm / 22.64"). I'll keep digging, but it seems the frame does not match production sizing.