Cicli Santini is an Italian bike shop located in Forte dei Marmi, which still exists by the way. The founder Ermanno Santini introduced the eponymous branded bicycles in the 1970s and there were still some made during the 90s. During this long period, quite a few exceptional bikes with the quadrifoglio (shamrock) has been made. Most of them have been made by Gino Vanni, a very skilled frame builder who made frames also for Fanini.
One of the typical motives Vanni used to drill 5 holes in a special cross scheme into the bottom bracket shell. This Santini road frame set shows this signature detail too. The frame, presumabely made on Columbus SL tubes, is very well made indeed and with it certainly doesn't lack the technical finess.
The brake cable is routed internally, which wasn't really that special during the 80s. But both shifting cables are routed inside the frame as well. And for that reason you have one little outtake hole in the chain stay and one really tiny one on the seat tube. The inside of the bootm bracket shell had to be adapted too. The shifting levers are also to be positioned on the top of the down tube, rather then on both sides.
A beautiful base of a high class Italian classic bicycle.
Rear axle width: 126 mm
Bottom bracket: ITA
Steerer length: 186 mm (threaded part: 37 mm)
Seatpost diameter: 27.2 mm
Front derailleur attachement: braze on
For 700C rims (28" wheels)