I have a New Albion Privateer that I built up a couple years ago, but lately I've been questioning my choice of frame size, and am considering swapping out the frame for a different size. I have two other similar bikes with similar geometry - a 2011 Bianchi Volpe and a 2008 Raleigh One-Way.

Published Volpe geometry, 51cm nominal:
Seat tube, C-T: 510mm
Top tube, effective: 525mm
Top tube, actual: 511mm
Chainstays: 425mm
BB drop: 68mm
Head tube: 120mm
Front-center: 593mm
Seat tube angle: 74.5º
Head angle: 71º
Bike is set up with a Gilles Berthoud Aspin saddle on a Velo Orange Grand Cru setback seatpost, and 80mm Velo Orange tall stack stem with one 10mm spacer


Published Raleigh geometry, 53cm nominal:
Seat tube, C-C: 500mm
Top tube, effective: 530mm
Chainstays: 425mm
BB drop: 55mm
Head tube: 120mm
Wheelbase: 1029mm
Seat tube angle: 74.5
Head angle: 71.5º
Bike is set up with a Brooks Professional saddle on a Velo Orange Grand Cru setback seatpost, and 90mm 17º stem set to positive rise angle, with 35mm worth of spacers underneath


I can post pictures later, but based on those numbers, which size frame would you choose for the New Albion Privateer? (geometry chart below)

48 is clearly the closest to both.

If you know the fork length and offset of the first two bikes, then punch some numbers into here:-
Stack and reach calculator

Compare the results with the stack and reach of the Privateer.

That's a lot of work when the bike in question has very little head tube length variation and very obvious TT length increments. Why make things harder?

Gee... beats me, sure would be nice to see how extended the seat/ handlebars are from the frame, plus some sort of information on your dimensions. Ie; height, preferred seat height, reach . even a picture of you on the bike. ???