On the Allegro I have a Campi Professional head set and It fit perfectly. Somehow I have misplaced my calipers so I can't get any precise measurements but I did measure th rear dropouts and they are 130 mm so I am going with a 7 speed freewheel or an 8 speed cassette. I am really stumped as to why the owner would have had triple cable guides brazed to the top tube. I will have to run the rear derailleur cable down the seat stay and use a top pull front derailleur. It just doesn't make sense to me especially as there is a campi down tube shifter and down tube cable guide on the bike and there is still the cable end on the chain stay. Any thoughts as to why they did it this way? Also, what are the braze on s on the front fork and left side seat stay for. They are both threaded for something to attach to them. Are they for lights? The more I look at this frame the more confused I am getting