Originally Posted by
slanglois
To get back to the original thread, I have confirmed the Ultegra behavior on a different bike. Same issue, you can adjust the point at which the RD will shift from going to the small ring on the FD to the big ring, but not the point it will shift on the RD when going from the big ring on the FD to the small ring in the front. It will always do the shift in 2nd gear so the drive is quite cross chained. Maybe Shimano will fix this with a SW update but that is the difference between Ultegra 6870 and Dura Ace 9150. Maybe someone who has Dura Ace 9070 can try the same and add to the thread.
I have Ultegra 12-sp Di2 and have not tried to change that shift point. So, no idea if I have that behavior. I agree there would seem to be no reason not to allow this behavior. But I run big to 2nd gear often and it simply isn't an issue for me. I prefer to be able to stay in the large ring longer before it shifts to the small ring. This is more of a get of the top of a short hill type thing. I don't cruise in that gearing.
Shimano is known for being quite conservative in there specifications. I don't think they would allow this, and certainly as the default, if it were an issue.
Of course, bike frame geometry affects this and what works for me perhaps is more of an issue for others.
I may see how my system behaves. If I do, I'll report back what I find.