OK, it's time to upgrade to Di2. The trusty 7800 group has served well, I resisted 7900 and waited, but now the rear gear selection is getting a little tired, so maybe time to retire it. It came down to a choice of 9000 or 6870 and the Di2 option appeals.
I have a 2009 TCR Adv SL so can easily accommodate an internal battery and a mostly internal wiring setup, but in the frames current state, I would need to run the rear mech cable external, and this would look OK, especially as the frame is black.
I am considering modifying the frame for a full internal fit. To do this I would need to drill one hole in the rear drop out and enlarge the front mech cable drilling. On the 2009 model the rear drop outs are aluminium bonded into the tubes. The front mech is easy as the under BB hole is plenty big enough, it is just a case of enlarging the existing drilling on the upper BB area with a fine circular file.
I have attached photos showing where the cable exits the frame in its current configuration, where the hole would need to be drilled, and an example of how the original Di2 only frames from giant were drilled (this is what I want to achieve). Basically, the original TCR Di2 only frames were exactly the same in the rear except for this one hole in the rear drop out.
Secondly I am considering removing the existing cable stops that are riveted onto the frame tubes. I 'think' that this could be done quite cleanly as I can pass a piece of paper between the stop outer edge and the tube, so it appears that the frame clear coat was applied before the stops were fitted, however, the unknown is whether the stops are both riveted and bonded to the frame. I am worried that if I drill the rivet heads out that the stops still don't budge. If they were bonded then removal could be a bit messy.
The frame is well out of warranty and re-sale is not a concern. So, I would like to here from anyone out there who has attempted similar or who is a bit of a frame structural expert.
Photos are here: https://onedrive.live.com/?cid=CE461544A39EEF41&id=CE461544A39EEF41%21473
Thanks in advance for any info/advice.