Di2 11 speed on rim brake steel frame: clever/stupid/goofy solutions?

[benadrian]

I recently bought a mechanical brake Di2 11 speed group from Clean39t. I've never owned or used Di2 before. My intention was to see if I liked it, but also I knew I'd have some kind of fun challenge and project to fit it on to my rim brake, steel frame road bike.

Before I did anything irreversible to the frame, I wanted to try out the Di2. So I came up with this craziness. I took a Gatorade bottle and put a small hole in the bottom. I placed this bottle in the seat tube bottle cage. I put the battery and B junction in the bottle. I then ran the FD, RD, and main wires to junction A tightly along the frame and zip-tied them down. I was able to tuck any excess wire into the seat tube bottle. Ugly, yeah, but it went smoothly

So yeah, Ultegra Di2 and kicks the pants off of my mechanical 105. So now, how do I do a more permanent installation?

This is a classic steel frame. There's no oversized shaping or tubing in which t stuff shifting electronics. There are vent holes in the BB to the down tube, seat tube, and chain stays. Annoyingly, there's no way the 4 port B junction will fit through a vent hole in the BB. I'm pretty sure there's enough room to fit wires around the BB sleeve though, and enough room to get the di2 cables into the seat tube, downtube, and chain stay. So, I have a few options.

As Internal As Possible
I could probably fit the junction box in the seat tube. Then I'd have to drill a downtube hole, a seat tube hole, and enlarge the chainstay vent hole. That would be some crazy routing for a steel frame, but the most elegant if I pull it off.

Internal Battery
Get one of the external mounted 4 port, under BB junction boxes. Drill one hole on the bottom of the BB to run to the seat tube battery, then do very nice and secure external cable routing.

Nicer External Routing
Find a case or bag like I'm doing with the water bottle, but mount it in a slick way under the downtube or in the down tube/seat tube junction area. No drilling, just route as cleverly as possible.

Abandon this crazy idea
Flip the Di2 and go withe Wheeltop (no real support), Force AXS (expensive, will need a new freehub body, cranks, BB, etc), get the nicest Ultegra/Dura Ace mechanical everything that I can find? Give up on my steel frame road bike idea?

Thoughts?

[prototoast]

Even with frames designed for it, routing Di2 wires through a steel chainstay is a major PITA.

[robt57]

Shimano SD50 E-tube Di2 Wire Cover Set. Come in white and black. I put these on a Scott Addict LTD in 2016 and my friend still has the bike and they show no signs of dislodging.

Trick is to solvent clean where they will get adhered to, and keep your fingers off the adhesive side once you pull the protector off to install. You shoud/could along the chain stay wrap over with bar tape or something for slap protection so don't need full run of cover on CS. The Scott is black nude cleared over carbon and they are pretty much invisible.

https://www.universalcycles.com/shop...OajRcVSMCb0ghI

You did not say of 11 or 12 speed.

Oh, and you can use one of these to house an internal battery in. Even has a 6 port B junction for SD-50 wires [11s e-tube].


https://www.universalcycles.com/shop...s.php?id=70432
Shimano SM-BTC1 Di2 Bottle Cage Battery Mount


If you are going for pure aesthetic, sell the Di2 for ASX. If you have a black frame IMO the black e-tube covers will be nearly invisible from more than 2-3 ft away.

[benadrian]

Originally Posted by prototoast

Even with frames designed for it, routing Di2 wires through a steel chainstay is a major PITA.

Yeah, it seems like it.

One of the reasons that I wanted to have a steel frame, medium reach rim brake road bike was to have something that was easy and fun to work on. Something where I could quickly swap parts, try experiments, and just have a toy to play with. Doing an internal Di2 install just seem to crap on that idea.

Bun man oh man, the shifting is so nice. And one long lasting battery rather than the multiples on my AXS bike... very cool.

[robt57]

Originally Posted by benadrian

Bun man oh man, the shifting is so nice. And one long lasting battery rather than the multiples on my AXS bike... very cool.

Yeah, the front is as good as it gets, and the auto trimming function with the overshift then auto trim after is the shiz!

Don't bother trying syncro shift IMO. When you shift yourself you know when to get the watts light on the pedals for the shifts.

[Look585]

Are you willing to learn to cut & splice the Di2 wires? That has opened up a number of clever alternatives for me.

The SD50 e-tube wires are ~3mm diameter once you cut off the connectors. I have been able to feed these 3mm wires out through various vent holes (BB cable guide hole or BB drain hole, rear dropout vent hole, etc) to avoid or minimize drilling the frame.

Cutting/splicing also allows for the elimination of the "B-junction" as you can splice the 4 wires together. The B-junction is a simple connector, there are no "brains" in it (unlike the A-junction).

Below are examples of cutting off a connector, fishing through an existing (small) hole without modification, and splicing the connectors back on.

[benadrian]

Originally Posted by Look585

Are you willing to learn to cut & splice the Di2 wires? That has opened up a number of clever alternatives for me.

The SD50 e-tube wires are ~3mm diameter once you cut off the connectors.

Cutting/splicing also allows for the elimination of the "B-junction" as you can splice the 4 wires together. The B-junction is a simple connector, there are no "brains" in it (unlike the A-junction).

My day job is designing guitar electronics. I've build my own amps and effects pedals. Wire splicing is no big deal. Are Di2 cables coax or dual conductor?

Cheers!

[Look585]

Originally Posted by benadrian

Wire splicing is no big deal. Are Di2 cables coax or dual conductor?

Cheers!

Dual conductor. Strip off the (admittedly tough/hard to strip) outer casing to reveal red and black insulated multi-strand conductors. Strip the inner insulation. Splice and re-insulate.

I use heat shrink solder butt connectors to splice the inner wires and then seal up the outer with a length of 3:1 glue-lined heat shrink tubing.

[glepore]

I have 3 bikes with "external" Campy EPS with a internal seattube battery.

I ran the wire from the stem junction down the downtube, secured with a ziptie. I then went in thru the vent under the bb on 2 of the bikes and drilled out the screw hole for the cable guide on the third.

I did not drill any other holes-the derailleur wires run back out the bb hole - the rd wire has one zip along the ss and then is placed thru the cable stop slot and to the the rd-, the fd wire just runs up to the fd. Excess is below battery in st.

[benb]

The idea of cutting and splicing the wires is interesting but only if it allowed a truly hidden setup.

Otherwise I kind of lean towards keep this frame built the way it was intended to be built, it would look more elegant that way.. if it's old enough that wired electronic is a kludge on it then leave it mechanical or get a wireless SRAM group. Take the Di2 group over to another frame that is more accommodating of it.

Funny thing for me is I have been riding on frames designed for Di2 since 2011 (first frame was external wiring but with channels for it, then since 2016 on one setup for internal) and yet have still not tried it. My mechanical stuff 100% refuses to break. If a brifter broke that would probably kick me to try it. A broken derailluer would be a "hard to decide" situation.