lm getting to be a real nerd about this bike , l wanted to find out how it was possible to make such a light frame. The tubes are standard from the exterior but they are elliptical inside where the butted surfaces require the most strength they are thicker and much thinner where not. I found this explanation ,
Available in standard and OS diameters for high performance road frames. The utmost stiffness is assured by the tube thickness distribution according to the three axis. The inside section shape is elliptical in the butted section and the thickness butts extend in thin strips along the tube.
Few more photos