dunno wrote:
Thanks, my 5 port is mounted inside the stem, I never need to go in there.
Sorry for all the questions but just to be sure before I order everything do I need the junction b boxes if I intend to run the cables directly into the 5 port in the stem?
I'm still not understanding the purpose of the b junction-are they used as a cable extender? Thanks mate
It can be used as an extension and also a kind of wire splitter/hub junction like how a cable tv splitter works or a powerstrip to get multiple items plugged into 1 single power outlet.
Example as I recently upgraded my TT bike to Di2 running with a 3 port Junction A. Parts were: 2x bar end shifters, 2x brake shifters combo, FD, RD and battery. That is 6 total items that need to get connected to the Junction A in order to have the whole system working and the math doesn't work out this way. In order to get my system to work for all of the pieces I connected a few of them to 2 different Junction B's (each 4 port ones) and then 1 cable from each of the B's to the A. Even if I went with a 5 port Junction I'd still need at least 1 Junction B to get it to work.
So I actually wired mine as follows:
Left bar end shifter, FD & battery to Junction B #1 + 1 wire to Junction A
Right bar end, right basebar shifter & RD Junction B #2 + 1 wire to Junction A
Left Basebar shifter directly to Junction A
I might've transposed the left/right basebar shifter on which on actually plugs directly into Junction A though but you should get the gist of it. I personally chose the MT800 Junction A because it has built in wireless/bluetooth and a digital display for gear, shift mode and battery charge level. Worth it to me despite having to run extra wires and 1 additional Junction B over a 5 port Junction A (and trying to remember the light flashes for battery level or having to get a separate wireless unit which means more wires and connections to account for).