Italian and German Frame Sizes
I just moved to Zurich from California and have been browsing some of the online market places here for a new road-style commute/errand bike. I've noticed that a lot of people describe frames in both Italian and German sizing, i.e., 56 Ital/57.5 Deutsch. The German size seems to be pretty consistently 1.5 cm larger than the Italian one.
Does anyone know what these measurements represent and which corresponds to the "American" size I'm used to that measures from the BB to the top of the seat tube?
I don't know for sure but, from your description, I assume that you're talking about the difference between center-to-center (center of the bottom bracket to center of the top tube) and center-to-top.
In the US center-to-top is more common but some bikes are marketed both ways.
Good catch -- in retrospect I feel like I should have been able to figure that one out myself Thanks.