Di2 1x minimum components

Discuss light weight issues concerning road bikes & parts.
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brearley
Posts: 384
Joined: Mon Aug 11, 2008 10:08 pm
Location: Hull

by brearley

Asked in the di2 section in cycle chat but had no reply

Next year I'm going di2 hydro disc and need to know what components I can get away with having as a minimum

Obviously need shifters and rear mech, there won't be an etube wire going to the left shifter
Can I use a 3 port connector to go direct from connector to rear mech?

Can I just charge the internal battery through junction A?
I plan on having the 3 port junction near the bottom bracket inside the frame as I often remove the chainset anyway

I'll most likely be on ultegra 8000 series but steadily buying parts on the way

From my limited understanding my list so far is :

Shifters
Rear mech
3 port connector
Etube wire from shifter to 3 port
Etube wire from rear mech to 3 port
Internal battery (does this connect to the 3 port?)

by Weenie


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ms6073
Posts: 2888
Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

With the availability of the Shimano SW-R9150 satelite shifters, I would ask are the ST-R8070 shifters really necessary for a Di2 1x setup? I am suggesting sourcing something like:

TRP Hylex RS single speed disc brake system
Shimano SW-R9150 Remote Shifters
Shimano EW-JC130 Y-Split cable
Shimano EW-JC200 Inline Junction Port (connect remote shifters to y-cable)
Shimano RD-R8050 rear derailleur
Shimano EW-90-A 3-port Junction A
Shimano SM-JC41 Junction B
Shimano BT-DN110 Battery
Shimano EW-SD50 Di2 wires (1 each downtube, derailleur, battery)
Michael - The Anaerobic Threshold is neither...

Belshazzar
Posts: 15
Joined: Wed May 15, 2019 9:55 pm

by Belshazzar

In theory that will work. However, you will have to place the A-Junction somewhere accessible for charging purposes, and depending on the size of the bike, the 1600mm wire from the rear derailleur *might* be too short. I would really recommend adding a JC-41 and a wire to the left hand shifter. Then you have an extra 3 buttons to configure however you want, for example if you want to have both buttons on each side shift one way, E-Tap style. Just opens up more options and costs an extra, what, $40?

Ritxis
Posts: 432
Joined: Fri Jun 01, 2012 3:00 pm
Location: San Sebastian

by Ritxis

as you say.
Basic components;
Shifters
Rear mech
Battery
Junction (EW90 or RS910)
as a function of Junction A, the cables you need..........

example; with RS910 I would do it like that, if you are not going to use a SW-R600 or SW-R9150

1 cable shifter to shifter
1 cable shifter to RS910
1 junction B (SM-JC41) for internal conection, with 1 cable to battery and other for rear derailleur (the junction you can avoid it by attaching the cables directly)
1 cable junction B to RS910 (if necessary, since the longest cable measures 1200mm, you could place a connector JC200* or d-fly (WU111) and other short cable

* ? in the figure
Di2.jpg


DeeHubbs
Posts: 104
Joined: Tue Mar 31, 2015 11:05 pm

by DeeHubbs

You need one A-junction for the system to work.
The A-junction can be inside the frame, and pulled out every few months to charge the battery. BUT the a-junction also functions as the micro adjust on the cassette. If you switch wheels, or get wheels from neutral service in a race situation you might want the a-junction accessible.
For a minimal setup I'd go:
-Wire from Right shifter internally in bars to
-RS 9100 bar end a-junction, internally inside the bars, then following the brake cable to enter the frame to
-B-junction internally placed in the frame
-to battery
-to RD.

4x cables, 1 x a-junction, 1x b-junction.

DeeHubbs
Posts: 104
Joined: Tue Mar 31, 2015 11:05 pm

by DeeHubbs

I basically have the same set up.
I go left shifter to right shifter to a-junction into b-junction inside the frame out to FD out to RD out to Battery.

brearley
Posts: 384
Joined: Mon Aug 11, 2008 10:08 pm
Location: Hull

by brearley

DeeHubbs wrote:
Thu Jun 13, 2019 10:49 pm
You need one A-junction for the system to work.
The A-junction can be inside the frame, and pulled out every few months to charge the battery. BUT the a-junction also functions as the micro adjust on the cassette. If you switch wheels, or get wheels from neutral service in a race situation you might want the a-junction accessible.
For a minimal setup I'd go:
-Wire from Right shifter internally in bars to
-RS 9100 bar end a-junction, internally inside the bars, then following the brake cable to enter the frame to
-B-junction internally placed in the frame
-to battery
-to RD.

4x cables, 1 x a-junction, 1x b-junction.
That sounds great. So instead of the usual stem mounted 3 port or 5 port A junction I can use the bar end junction and then an internal B junction somewhere near the bottom bracket?

So if I've got this right:

Shifters
Rear mech
Battery
Ew-rs910 junction A
Sm-jc41 junction B
4 wires between

Do I need the proper shimano charger? Looking online it's possible with just a standard micro USB charger?

engi
Posts: 49
Joined: Wed Apr 03, 2013 5:09 pm
Location: AZ, USA

by engi

I actually just built a 1x Di2 road bike (breakaway style, for travel). Here's what I used:

-Ultegra 6870 rear shifter (11sp) with a generic Chinese brake lever for the front
--wire from shifter to 3port Junction A (at the stem)
-3port Junction A
--wire from JunctionA to Junction B (at the BB)
-Junction B (internal battery style), 4 port
--wire from Junction B to internal battery (housed in downtube)
--wire from Junction B to rear derailleur
-Ultegra 6770 long cage rear derailleur (10 sp)

The system is a 1x10, because it's RD-dictated.
FWIW, I'm running a 40T narrow-wide oval front ring and a 11-34T cassette.

Technically, i could elminate Junction B and plug the battery into junction A, but it would not have worked for me because the frame is split up at the downtube. If your frame is 1-piece and you don't mind running longer cables, then sure, you could eliminate Junction B portion.

Regarding chargers, I'm not sure what plug is on the bar end Junction box, but for the EW90 (3 port), it's a proprietary plug, not a micro USB. I was lucky in that my wife's bike is also internal Di2, so I'm using her charger.

There are also ways to build it cheaper using a DIY internal-style battery that's meant for RC cars/planes (and you can charge it with a cheap charger), but you would need a Shimano proprietary battery "chip" somewhere in the system. What I did (this was my rev0, before current setup described above) is got a cheap external battery mount, cut out the chip portion, and soldered that inline with leads from the RC battery. The latter procedure is a PITA, somewhat fragile (even when epoxied over) and a bit bulky also (got the battery "package" down to 70g...internal Di2 battery is 50g). I used EW67 for Junction A, which already has an integrated wire going to the shifters. You'll end up saving $100-150 this way over the standard internal battery setup, but I'm not sure it's worth the hassle...and I like to DIY stuff on the cheap.

DeeHubbs
Posts: 104
Joined: Tue Mar 31, 2015 11:05 pm

by DeeHubbs

brearley wrote:
Thu Jun 13, 2019 11:17 pm
Do I need the proper shimano charger? Looking online it's possible with just a standard micro USB charger?
Yes you need a Di2 charger. They have a proprietary plug end that goes into the Di2 part. Its not just a charger, it's also a diagnostic tool that allows you to check and update firmware. BUT Only on PCs. If you are MAC only get the Inline Wireless Transmitter (WU101 or WU111) and you can bluetooth to your iPhone. BUT make sure you have an latest version of the battery (BT-DN110) that supports the Inline Wireless Transmitter.
You really can get away without a charger, if you willing to go to the shop every 3 months to charge it. Just pull the seat, seaports and battery and leave that part plugged in at the shop (or a buddies place) for a night. The battery will last that long, I charge mine once in April, once in July, and it goes to bed in Oct and still has some charge left again in April. And with the WU111 you can see the battery level on your iPhone or Garmin Computer.

by Weenie


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