OuterMarker

I'm about to do my first Di2 build and everything looks unfamiliar. All of the stuff online seems to be from the first generation of Di2, so aren't that helpful anymore.

Goal
I want the cleanest Di2 install and don't care about the cost.

The Plan
Run Ultegra Di2 with no visible battery or junction boxes. I think that means I will have a bar end junction A box that is connected to the STI levers via a Y Connector(?). A wire from the bar end junction box goes down the downtube, around the bottom bracket, into the chainstay and connects to the junction b box. Wires from the junction b box connect to the rear derailleur, front derailleur, and seat tube battery.

Questions
Is the Di2 Battery Charger something that goes on/in the bike, or is it just something that allows me to charge the battery with an outlet?

How does the Wireless Module fit in the diagram? I know it goes in the handlebar, but what part of the Y Connector does it attach to?

How do you attach the battery to the seat tube? I see that there are some specific adapters, but they only seem to be for a small number of manufactures. If I buy a "Di2 ready frame" that includes a seat tube, should I assume that the seat tube can accept the battery?

veganbikes

The battery charger is to allow you to charge the battery. You want the SM-BCR2 because it can now do the PC linkage as well.

I have the Wireless Unit and maybe it is my phone or something but it doesn't really work well for me. I have gotten it to work but not often. Mine happens to be in the seat tube but maybe putting in the bars might help and I may end up doing that when I install my bar end junction box (which I need to do at some point)

The seatpost will take the battery you just need one of the various mounting plugs to fit your seatpost. ENVE, FSA, ZIPP, Ritchey, PRO and others make them. They are typically plastic or rubber and just help you shove it up in the seatpost and prevent rattling or falling. Mine is Ritchey in a Ritchey seatpost and it has worked fine for many years.

Not that you can see anything well as I need to take better photos but my Di2 wire at the front is actually zip-tied along with my brake cable so it is quite clean and the wires only stick out enough to leave the chain stay to get to the RD and the seat tube to get to the FD:
https://www.pedalroom.com/bike/found...titanium-34057

I imagine on some of these integrated handlebars and carbon jobbers you can now clean up every single wire and shove into the steerer tube and frame and you won't see a goddamn thing but Ti is fly.

sch

Charger is separate, plugs in via connector on 910 barend junction so need a 110v in US wall outlet to plug charger into
and that the bike can be close to. From this search you can look at some videos suggesting Y connector not needed
https://duckduckgo.com/?q=Di2+bar+end+junction+box+A&t=opera&ia=web&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DcON3w1I L_7k&pn=1&page=1&adx=artexpa&sexp=%7B"artexp"%3A"a"%2C"prodexp"%3A"b"%2C"prdsdexp"%3A"c"%2C"biaexp"% 3A"b"%2C"msvrtexp"%3A"b"%2C"bltexp"%3A"b"%7D

Also the Shimano dealer manual is referenced. Wireless module plugs into any open port. Haven't looked at the literature lately but seat tube batteries to my
understanding attach to the seat post which must be a Di2 compatible and the battery is small enough to fit any seat tube.

Barry2 

The wireless unit D-Fly has a plug on each end. I hung mine below the seatpost mounted Di2 battery.
I coiled the cord between the battery and D-Fly so that the D-Fly remains high in the tube and not down by the metal BB.
Battery to D-Fly to Rest-of-Bike
This places the D-Fly in the seattube (Carbon) and not near the thicker and stronger seatpost or worse yet inside a metal drop bar..
Seems to work fine. I've even used it for a wireless firmware flash.

D-Fly did not come with a cable, get the shortest one you can,

Barry

OuterMarker

So, after LOTS of youtube videos, I have a better idea of what to do. Here is my plan for the frame:



But, when it comes to the handlebars, I have a question. The "normal" way seems to be this:


The question I have, is why not use the internal cable routing holes in the handlebars? Is there any issue with attempting routing like this?

OuterMarker

Sadly, I was thinking about this in my sleep and came up with some more combinations:

This one appears to avoid sharp cable bends:




And this one uses the Y-cable:


Does anyone know which way is best?

Steve B.

Using the h-bar mounted A junction begs you to use a handlebar drilled for Di2. Much easier to run wiring.

OuterMarker

I am trying to avoid running the wires on the outside of the drops as I don't like the feel. I have a few bars with internal cable holes that are normally used for mechanical groupsets. I want to use those holes to run ALL the Di2 cables so they are internal.

TerryDi2C

My setup is this:
https://assets.bettershifting.com/up...etup_terry.png
(everything through the bars)


I tend not to use the Y-splitter, because I think it is rather bulky. The one thing that is great about it is the way it allows you to disconnect the front of the bike from the rest (in case of troubleshooting for example).

My bike's build log can be found right here: https://bettershifting.com/build-log...trix-disc-di2/

As for which is best, it's up to you. Di2 itself doesn't really care how things are connected, as long as they are .

There are a couple of more diagrams here: https://bettershifting.com/bar-end-j...llation-guide/
Most of the information is taken from the Shimano dealer manuals, they also have example wiring schematics.
To find a dealer manual just go to https://si.shimano.com and enter R8050 in the search box. Then open any of the DM files it lists.

OuterMarker

This is exactly what I was looking for! I just found your website a few days ago and it has helped a ton, but I never saw the build guide section.

I was worried about the size of the Y-splitter too. I also really like the use of the SM-JC41 connector. I tend to swap parts around my bikes a lot, so this will make a handlebar swap much easier. What's your reasoning behind the wireless unit location? Why not put it inline with the bar end junction box?

TerryDi2C

The shortest wire is 150mm, so putting it inline would put it somewhere halfway in the handlebar drop.
There isn't a whole lot of space there in my Easton EC70 bars, only just enough to get two wires through.. getting the EW-WU111 somewhere nice would be a hassle ;-).

Of course it could also go in the handlebar near the stem.. maybe I'll do that next time.

The SM-JC41 in the image linked in this thread is located in the downtube, near the bottom bracket by the way.. but there is no limit to the amount of SM-JC41 units. They're just 'dumb' 4 way splitters. You can have 0, 1, 2, 3 or 20 if you like

OuterMarker

Oops, I got the part code wrong, I thought the JC41 was one of the 2-way splitters. I will put the JC41 in the downtube, but I think I will use the JC200 2 way junction between the frame cable port and the bars. That way I will be easier to remove the bars without undoing all the Di2 cable routing.

Steve B.

Real common to stick it in the seat tube. Wrap some foam around it so it doesn' rattle.