After reading a few posts on ST and some references to the weightweenies forum http://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=87102&hilit=cateye+button, it looks that getting a Di2 Ultegra system for a tri bike for ~$1500 is doable. Di2 Ultegra TT is not supposed to be available until mid 2012 but the system will be available for road bikes this month. What I am not sure of is how difficult it is to convert the road system to TT. It should not be too difficult to wire the 2-switch road system to the 4-switch (2 on the extensions + 2 on the brake levers) as this is a direct current system with all the “brains” in the derailleurs.
Doing a quick search, I can get the RD for $340, FD for $310, internal wiring kit (including battery & wires) for $600, 4 cat-eye remote shifter buttons for $50. Add $100 for brake levers and $100 for miscellany for a total of $1500. Worst case scenario is that I totally screw up and have to wait for the ultegra Di2 TT system to come out in 6-8 months. The Dura-Ace kit is $2300; I guess I need to decide if saving $800 is worth taking on such a project. Any ST advice would be most appreciated.
I’m pretty sure it’s not as simple as that. The trim control unit is on the bars too, so the signal that goes down the 2 wires isn’t just high/ground. Also the two shifters are wired together and then that’s 2 wires to the ‘brains’ so there has to be some coding in there to allow it to know if you want to shift front or rear mech.
There are other forums where they have got the soldering irons out and had a play and they may be able to help. Your money, but I’d personally want to be pretty sure of what I was doing before I risked frying $2400 of gubbins.