Originally Posted by
Koyote
Fair enough, and thanks for indulging me.
When people want to upgrade to Di2 because they think it shifts better, I like to point out that it doesn't. A good mechanical Shimano groupset, properly-adjusted and maintained, shifts as quickly and cleanly as Di2. But Di2 does indeed require only a small tap on a paddle (not a press or push), and I have found that Shimano's mechanical 11sp groupsets do indeed shred RD cables rather quickly - usually within the shifter, sometimes to catastrophic results.
Are you going to get the bluetooth dongle? I highly recommend it, as it allows you to customize shifting with your phone (rather than plugging in a computer) and you'll get gearing and battery level readouts on your gps computer.
One of the reasons I went to the V3 EOS system was to get the gearing and battery level data. So yes, I'd like to include the "blue tooth dongle", but I'm not clear where it goes in the system. As I understand Di2 so far, I'll need wires from the R & L shifters to the A junction box which I plan to mount under that stem alá EPS, then a wire from the A box to the 4 port B box. The other 3 ports of the B box then take wires going to the battery, which I plan to mount in the seat tube, the front and rear derailleurs. So where/how exactly does the blue tooth "thingie" go?
BTW, I do have a coping of Shimano's dealer manual for the R8050 series. Unfortunately, Shimano's manuals are less than crystal clear. In an apparent attempt to cover all possible cases, the document ends up being poorly organized and it's diagrams are often not enlightening.