Internally routing or Hiding Di2

EDIT: posted in wrong thread.

Ok I'm having vague thoughts about changing over to 2x Di2 set up on my Curve which currently has the cables running externally down the downtube with bolt on guides. I want use an internal battery and junction boxes and at first I thought I'd have to have the frame drilled but after looking at again and some of the products in this thread I think there might be a way to almost achieve it without modifications. However I don't have any experience with Di2 thus far so I might be talking nonsense?

At the handlebars I would use a bar end junction box and either have the wire come out at the clamping area (as per some pre-drilled models) or run externally with the brake hoses and then along the underside of the stem to the headtube. Then could I use something like the Ritchey headset to have the wire enter the headtube (44mm) and run down the down tube to the BB.

The BB is T47 with external bearing cups so I assume there would be enough room to fit wires around it coming down from a seatpost mounted battery and linking upto the junction box. Then in terms of wires exiting to the derailleurs, there is a fairly sizeable drainage hole on the underside of the BB shell for the front derailleur wire which would then go through an existing cable stop. As for the rear there is an unused bottle boss hole at the end of the down tube it could exit from and then be routed externally along the chainstay (internal routing is out of the question because the chainstay begins with a solid yoke).

Anything I've overlooked or is this actually doable?

Also I think the Orbea option for a stem that routes wires to the headset is reasonably nice looking:

seems do-able, keen to know your progress, the key piece of hardware is that headset

I've got a BMC one which is similar. Waiting to give this a go for next summer's sunday best bike

Reading into it more I'm assuming the Di2 wires (2mm) would fit through the holes (drainage and bottle boss) but the plugs (5mm) wouldn't ? So that would mean cutting off the plugs and then soldering them back on after routing?

Nice! I keep up with you're current projects thread so I'm eagerly waiting to see you build this fully internal frame!

This is not too difficult if you are at all handy with a soldering iron. If you are cutting and splicing you may decide not to use a junction box in the frame, and simply join all the ends together and cover with heatshrink. That way you only need to purchase half as many of the ridiculously expensive cables.
Don't forget to include an external junction between the frame and the handlebars.

If people dont mind selling a kidney (or both) bastion have made this tidy looking fork/cockpit setup that is fully internal. Apparently may be available aftermarket

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The tech behind it is crazy but mixed feelings about the HR Giger vibe it radiates.

Another example of someone doing fully cables on a steel frame. I don't think the oversized headtube looks so out of place on it but I think the large downtube helps with that. @PhilDAS you made any progress in your plans to weld up something similar?

No not yet. The planned build was for a summer road bike but for this year, I'm just going to hang onto my CAAD12 and I'm hesitant to replace it now anyway because it rides so good and will be lighter than I'm able to make a steel frame.
However, my plan is to use a BMC fork which has a squared steerer that is flat on two sides allowing the cables to run into the headset that way

Check it: https://www.bikeforums.net/bicycle-mechanics/1230520-9150-controlling-9070-a.html

impressive, but not sure I'd drill holes in this

All holes are in sensible places. They range from 1.8 to 2.5mm. There's pics and vid in the Bikeforums thread.

That pic is showing the charging plug and jack harvested from the BCR2 and the A-junction, separating the loom between the frame and fork, hotglued into place behind the head tube. There's no hole drilled there.

ETA: huh, you grabbed that pic from the build thread, so you saw the process. Why'd you illustrate your comment with that pic?

Looks like enve will be selling their integrated fork/stem/bars system at some point. May be a good bet for some if you have the cash. Works with 44mm head tubes but you need external cup on top. I think it looks pretty good although im not usually a fan of the external top cup. They only have one option of forks which is a bit of a middle ground geo/clearance wise so may not work for all.

https://www.enve.com/integrated-road-system/?fbclid=IwAR1H1oW4yux2i4uNxmTGfp7hmqkvkvu7TVsZQVNFnlGCBzOJkvshU5Ddc6s

My latest project is fully internal again, including di2, dynamo/lighting cables and hydraulic lines. Not really using oversized tubing:

do you have any more build details on this please :)

What kind of details are you looking for?

It's a custom build frame and fork with drilled steerer for internal routing. Has a polished (by me) Ultegra RX derailleur, DT 180 rear hub and Praxis Works Zayante crankset.

Sorry I meant more photos! Very lovely bike..

Superb as usual dude. Very interested to know how you went about polishing the RD? I looked at the pressed pins and backed off, went to SRAM as it's all easy to pull apart.
Calipers polished too I see.
Did you feed everything at the top of the HT?

I'd be very interested to see more of the routing with the bars, stem, steerer, headtube if you have any photos

Haven't got too many pictures, but hopefully this helps.

I cut a decent part out of the steerer to feed the brake hose, di2 and rear light wires from the fork to the downtube:

Basically the rear light and switching wires enter the fork from the bottom. The di2 wire and brake hose go through the dropbar, trough the stem and into the steerer. Here you can see a bit of the assembly without the dropbar (and my dad fitting Land Rover tyres):

@Chak I didn't remove the pressed pins, just polished it partially assembled. Maybe next time I would drill out the pins and just make some new pins:

Curious how the front brake hose enters the fork blade? Does it go down the steerer and then through the lug at the crown? Whole set up is super cool.

Yeesh. Reckon that's a little more concerning than tiny holes in carbon