guadzilla

Hi all -

I am running Ultegra Di2 10 speed on my TT bike. I'd like to upgrade it to 11 speed. Can someone confirm if all i need to do is:
- buy an 11 speed 6870 Di2 RD
- reprogram the shifters?

Or is there a little more to that?

And can i reprogram the shifters myself, or do i need to take it in to a bike shop?

TIA!

notmyke

Assuming you're running the newer 10speed stuff (not the 79xx series)...

The 6770 Di2 shifters *will* work with 11-speed cassette/derailleur - keep in mind that the shifters are really nothing more than a micro-switch that sends a "move this way" or "move that way" signal to the CPU (SM-EW90). So, it really doesn't care whether the brain (and thus derailleur) are 10 ticks top to bottom, or 11 (or, presumably 12).

I can confirm because that's what I have on one of my bikes.

sch

The shifters send the same signals in 10 and 11 spd Di2, the RD moves a fixed distance with
each signalled shift, so a 6770 RD moves a tad more than a 6870 RD. The shifter will
work fine without an update to its firmware with a 6870. OTOH updating the firmware is not always a
bad idea. You can do it yourself of have a shop do it for a (presumably) nominal sum which would
probably be less than buying the necessary interface cabling. You can't mix 10spd FD and 11spd RD
however.

Contrary to what notmyke says, the shifters do send a digital signal specific to the shifter and are
not simple switches. The switch that is present controls a very small microprocessor ckt board in
the brifter that debounces the switch and sends the digital signal that tells the RD if R brifter or
FD if L brifter to move. It has to be this way because the cables have only two conductors and
the A or B connector boxes with 3 or 4 sockets allow any cable to be plugged into any socket.