So I’ve got a new 2014 S3 with mechanical Ultegra. How much aero am I giving up with the exposed cables vs. electronic? I have some Di2 parts on another bike I could swap, but I really like the mechanical shifting.
I’d bet that when you consider the oversized derailleurs (due to the motors) and other little details like the junction/control box and stuff, if there’s any difference at all, it’s got to be so minimal as to be essentially meaningless.