I’m thinking of upgrading my Felt AR to Di2 and I was wondering if anyone knows what cable lengths I’d need for a 54? Is it also better to go with an internal or external B junction box?
I was very pleased to see your post, since I am currently considering the same move with my 2015 Felt AR.
In response to your questions, the Felt Manual explains how Junction Box B can be installed internally above the bottom bracket. There are very useful diagrams in that manual explaining how to install Di2 wiring.
My question to you (and to the forum at large) concerns the cockpit, Junction A and charging. I have:
- a TriRig Omega X brake that I am keen to install up front; and
- a preference to hide Junction Box A (5 port) in a manner which still enables me to charge the Di2 battery quickly and efficiently without having to engage in fiddly unpackaging/repackaging.
Given my choice of front brake, I am naturally attracted by the TriRig Alpha X cockpit, but I am concerned about access to Junction A for charging and adjustment purposes. Could I ask what you are planning with respect to Junction A - internal or external? And (to the forum at large) what options are there for hiding Junction A in a stem or otherwise while retaining easy access for charging and for adjustments?
I have the same size AR and I believe I built it up with a 1000mm long cable and then 2 400mm for derailleurs. Then the 2 short ones for shifters. The extra di2 wire within the frame can always just be bunched up so always go longer vs short since the extra just sits in the tube. I have mine B junction installed at bottom bracket as previous poster states that’s found in the wiring diagram for the frame.
So are you looking for a TT setup since the Alpha X is a TT cockpit? No advice for you there if that’s the case. There are ways to hide Junction A but most don’t allow easy charging. I’m running a 3 port A junction in a standard place (attached to bottom of stem) for now. If I wanted more aero I could go with something like the 3T Integra stem that allows the 3 port junction to be put inside the stem (only alloy version I believe). I don’t know if the 5 port junction can be hidden inside the stem.
I’m sure there are other options out there now that I’m not aware of. Browse the Felt AR thread on here and you are sure to find SuperDave’s Responses about this.
HTA: yes, I am going for an aero set up (returning to triathlon after nearly 3 decades away!). I will take your advice and search for posts by SuperDave.
I never thought to actually look at the manual but it is helpful. It looks like the manual has the bike set up with an internal battery too. I didn’t think the battery would fit in the seat post, are you using internal or external battery?
Internal. The seat post is specifically made to use the internal battery using the clamp provided (assuming you have the clamp). It’s a great setup.
So it does work come with an internal holding spot. I talked to two different shops about it and they both said to install it externally on the bottom. Oh well I guess saved a lot of money buying the external one.
I built up a 2015 AR3 this spring with Di2. Very easy build, even for me as a first timer, following the felt pdf and the shimano install pdf.
For shifters to 3-port junction on my 42cm 3t aeronova bar (I hid mine in the 3t integra stem, but not sure that the 5 port would fit there) I think I used the 350mm wires, but I think the TT bar end and brake lever shifters include attached wires already.
I put my b junction below bottom bracket and the d-fly between battery in seat post and the 4-port b junction.
I really wanted my A junction hidden under the seat for easy charging and derailed adjustment but I couldn’t find a good hole to pass a cable and didn’t want to drill the seat post. The integra stem does have a small finger opening that you can use to push the button on the A junction (for adjustments, or to reset the crash protection feature - a other reason not to bury it inside the frame).
I think I used the 1250mm for the downtube, the 850 for the battery, 600 for front der from bottom bracket junction b, and 750 for the rear Der to junction b, but I can’t remember for sure- I basically just used the default wiring set that came from Ribble with my complete groupset.
Another option would be to put two junction B boxes inside the Integra team stem, to allow plugging in both of the bar end and brake shifters of a tt setup, and run the downtube cable to a third junction B in bottom bracket and mount the junction A on the rear chainsaw in front of the rear derailleur in-line with the rear-der cable (I. E. Junction-b in BB - > cable exiting at rear chainsaw to junction A - > short 350ish mm cable from junction A to rear Der (one of three ports still open on junction A)… Wouldn’t look quite as clean though…
Also, it is frustrating that more stems aren’t coming out designed for hidden junction boxes. For my AR3, I’m excited about the prospect of picking up one of the new junction-a replacements that are small enough to use as a bar end plug (new di2 durable stuff that comes out this fall?) and then you can use any length regular stem!
This is one of my favorite topics. You’ve already gotten really good advice, especial from IA guy. Everything internal, obviously. Junction B is a no brainer for internal. As has already been mentioned, the AR provides complete integration in the seat post. Bike shops are so incredibly full of fail.
Here are a few pictures for you to think about with your junction A. Happy to answer questions but I think they pretty much speak for themselves. The first two are mine from my B series and my AR (I prefer the Sigma classic XF for this) and the third is SuperDave.
In the SuperDave case, which is what I did on my mountain bike, you drill a small hole in the back of the bar and hide the junction inside the stem. There are plenty of hollow stems that make this possible. If you hate the idea of undoing a couple M5s once a month, then you can spend $60 on an extra junction A, which you can plus into the e tube that connects to the rear derailleur to charge the system. But that’s pretty lazy.
I hide my D-fly jawns inside the top tube behind the steerer, and if I didn’t want to drill into a bar, I could hide my junction A in there too.
Shimano might have your solution coming out soon if you are patient.
http://www.dcrainmaker.com/2016/06/shimano-dura-ace-power-meter.html
I have a 2015 AR2 and I just have my Junction A box mounted to the side of my stem so its behind the aero bars.
As for cable length, go with 1000 on the Junction A to Junction B. Longer is always better for internal routing. 350 or 400 from the shifters to the Junction A if the A box is at the stem.
The other thing to consider is that you do get power notification via the LED on the Junction A box, so if your battery is very low the red LED will flash.
Ian
Many thanks to all for the responses. gte534j: the new Shimano handlebar junction would be perfect, but I am struggling to work out how to add it to bullhorn/pursuit/aero bars.
Ideally, TriRig or 3T or someone would come up with a set of aerobars that allowed the installation of the new Shimano handlebar junction at the end of one of the aerobar extensions. I don’t know if that is physcially possible - I suspect it would require drilling a hole through the bottom of the extensions in order to thread the cables from the STI shifters. Hmm. I wonder if that is a DIY project worth pursuing?
I wouldn’t hesitate at all to drill the bottom of an aero extension behind the clamp so the new Shimano Bar end junction A could be placed inline downstream of an extension shifter. On the Alphas this would help place the wire right at the back of the notched extension riser. My Zipp extensions are notched at the bottom so I can wrap the wires tight out of the back and have them run down vertically behind the extension risers to the basebar.
I have two junction B’s in my Zipp Vuka Stealth for linking extension and bull horn shifters. Also have a DFly in there. 3 port junction A is tucked in behind front derailleur.
For a TT/Tri cockpit instead of one 5 port junction A’s or two junction B’s there is also the option of using the XTR internal battery external mount kit wiring junction that has 6 ports and functions as an expanded junction B.