saw this on DCRainmakers Week in Review: looks like its written by someone here

hope this helps

Need to decide if you are going to run it internally or externally and get the appropriate kit for that (battery, wires, junction box etc). Very easy to route the Venge internally, you should get most of the wires you need in a group and can buy extras if you need them.

Wow, thanks. I missed it on DCR's week in review apparently

Venge internal battery adapter. http://service.specialized.com/.../pdf/IG0436_revA.pdf[/url]

Venge di2 wiring cable stops
Specialized Part# S132000002
http://fcdn.roadbikereview.com/...-owners-grommets.jpg

Planning on internal wiring with the seat post battery

One question though. If I have 10 speed now can I use the 6870 as 10 speed and then convert to 11 later if I want? I'd like that if possible because the 6870 will accept up to 32T cassette

No. the 6870 RD will only run 11 speed.

I run the seat post battery in my Venge. Dont bother with the over priced adapter from Specialized, just wrap it in some foam and a couple zip ties. something like this. http://weightweenies.starbike.com/...php?f=3&t=115008

+1 on using some foam or leftover bar tape, works fine.

I've got a 54 Venge S-Works with 10speed Dura Ace Di2 with internal battery, I'm thinking about selling. It's the complete bike less crank and wheels. All very nice stuff.

I'm assuming this is because you only have a 10 speed compatible wheel?

If everything you are getting is 11 speed minus the wheels, I have read that you could remove 1 cog from the 11 speed cassette, add a spacer (not sure what size), adjust your di2 limit screws and essentially have a 10 speed setup. There is no software programming to make the 6870 10 speed.

When I've adjusted my own 11 speed di2 rear derailleurs, I've gotten into situations where it only shifts 10 spots due to the limit screws and fine adjustments. It tries to shift to the 11th spot, gets stopped, tries for 5 seconds then backs off. So it's possible. Whether it is ideal is another question. Not sure if it puts additional stress on motor if it keeps getting stopped by limit screws or if the shifts aren't as smooth if you remove a middle cog.

Well I've already got the frame and a 54 is prob too small. I'm on a 56.

If you wanted to part the DI2 stuff I'd be interested