# Need help on 1st generation Di2 wiring



## tom_h (May 6, 2008)

Posting this for a friend who is not a native english speaker. Also I'm primarily a Campy user, so Shimano's Di2 tech documents are bewildering to me.

Here's the issue --

My friend's bike frame broke in a crash, and he replaced it with a 2016 Specialized Sworks Tarmac frame, which is designed for internal cable & wire routing.

Friend is using 1st generation, 10 speed, Dura-Ace Di2 -- I believe that's 7970 series, but I'm not sure (I'm a Campy guy, remember!).

The LBS moved over this 7970 Di2 drive train to the new Tarmac frame.

However, the cable between the "Junction A" near handlebars, to "Junction B" under bottom bracket, was sloppily taped on to the outside of the frame! 
LBS claimed the cable was too short to be routed inside the frame. 
It looks so ghetto -- terrible -- and the tape is already curling up.

LBS told my friend this "junction cable" is:
a) discontinued.
b) was only ever available in 1 length, anyway.

WTF? That is hard to believe!

I've gone thru Shimano tech documents, but there's a dizzying array of slightly different series & part #s, and I'm not sure I'm even looking at correct diagrams. 

> > Any help in identifying a part# for a longer "junction cable" is much appreciated. 

The 1st diagram below shows the cable, but we need it longer than original "standard".

Shimano document # EW-7973 -- if that's even correct for friend's setup -- shows 2 available junction cables:

Y7E398010, EW-7973-1 Junction Cable (Short)
Y7E398020, EW-7973-2 Junction Cable (Long)

But there's also documents # EW-7972 & EW-7974 that only show 1 cable length -- very confusing.
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## rm -rf (Feb 27, 2006)

Sorry, I don't know the cables.

If you have to keep the external routing, you can use the Di2 cable tape. It's also called "Di2 wire cover". That should look better and last longer.

View attachment 314928


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## goodboyr (Apr 19, 2006)

Not sure but I believe there were a few lengths. Will try to dig up references. In any case, if you are handy with soldering small wires you can always extend cable. As well, seller "eapathome" on eBay sells harnesses and batteries for internal cabling for first gen systems. 

Sent from my SM-G900W8 using Tapatalk


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## rcb78 (Jun 15, 2008)

Complete 7970 wiring kits still show up in the Shimano B2B site that dealers use. They show stock on Short, Med and Long kits. That said, if he only needs one single wire, then a phone call to Shimano directly is in order, or do some ebay surfing.
The kits are complete (all wires) and show and MSRP of $250. The sizing just refers to the wire you happen to be looking for, the run from front to back.


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