It is possible to build a di2 system without a junction b but this involves running e tube wires from junction a to both the battery and derailleurs as well as the shifters.
Di2 junction box downtube.
Both the current and the previous generation di2 have a button on the junction box.
This junction a is required to connect the shifters via e tube wires to the downtube junction wire 3 port design one for downtube wire to bottom.
The sm ew90 junction box features an integrated battery level indicator charging port and gear index setup switch.
Shimano di2 ew90 junction a box 3 portthe removal of traditional mechanical cables in favour of electrical wires not only eliminates poor shifting caused by contaminates corrosion and stretching but provides effortless gear shifts features.
The di2 kit for my 2012 6 9ssl included a short mount that fits under the bb.
What does the button on the junction box do.
Di2 ew90 junction a box 3 port features.
Shimano junction a e tube under stem mount 3 port shimano s sm ew90 a 3 port junction a mounts neatly to the bike stem and connects with e tube wires from di2 shifters and the downtube junction wire.
As for mounting the pieces i ve seen a photo of the junction a box mounted using the oe strap to the seat tube below the bottle cage and near the fd if you had one.
If you use it combined with one of the old batteries external sm bmr1 sm bmr2 or internal sm btr2 it.
This junction a is required to connect the shifters via e tube wires to the downtube junction wire 3 port design one for downtube wire to bottom bracket junction two for shifter connection.
Depending on what battery you use the button does different things.
This means you d need to have two or three long wires in your down tube fd rd and battery or move the battery to your fork stem or top tube.
3 rs910 junction a box to be installed in the downtube of frame 4 4 port junction b for bottom bracket 5 ew wu111 dfly wireless bluetooth transmitter 6 battery bt dn110 to be installed in the seat post 7 bmc di2 parts 301102 di2 kit 8 and 213675 plug kit.
The sm ew90 junction box features an integrated battery level indicator charging port and gear index setup switch.
It can be run inside the down tube of the frame compatible frames only or outside it.
I m not familiar with a 2004 madone but wonder if the external battery mount from a later one e g.
