Originally Posted by
Spaghetti Legs
I'm not particularly expert on Bianchi but that is a higher end one. My guess is around 1980-82 based on under BB cable routing and portacatena dropout. The rear derailleur is Super Record. A racing Bianchi from this era would be Columbus SL but the 27.0 seat post suggests otherwise and my guess would be Columbus SP which was used on larger size frames (like a 59 maybe indicated on the BB?). Another possibility is maybe it is SL and the seat tube just needs to be reamed out. The BB is almost assuredly Italian thread on this one. Cool bike!
Thanks. The 59 frame size makes some sense. I only had a tape measure in inches and measured 23" (very rough) which works out to about 58.4cm so I am guessing you are right.
I forgot to mention the rims are Mavic G40s, not that that necessarily says much.