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  1. #1
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    di2 seatpost question

    I just converted my BMC GF 02 disc from 105 to ultegra r785 di2 (internal routing), which is amazing. First di2 build and first time riding di2.

    However, I've got the B junction box in the seattube right above the bottom bracket, and have now realized if I want to take the seatpost out of my frame, which I do from time to time to transport my bike upright in my ford escape, I will have to remove the bottom bracket to plug the battery back in. If I pull the seatpost out, the cord will come out of the b junction box.

    Is there any way to avoid this besides getting a super long cable for the battery? I think this is my only option but not sure; wanted to check before I eat 20 dollars for a new cord.
    I like to ride fast.

  2. #2
    tlg
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    Yes, you need a longer battery wire. There should be a few extra inches so you can remove the seatpost.

    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  3. #3
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    I use a wire with enough slack to pull the wire off of the battery. I use a rubber band over the outside of the seat tube to keep it from slipping down inside while it's not connected.

  4. #4
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    Got it, thanks. Does the extra wire inside the frame make noises?
    I like to ride fast.

  5. #5
    tlg
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    Quote Originally Posted by marathonrunner View Post
    Got it, thanks. Does the extra wire inside the frame make noises?
    Should be no problem.
    Wires in the downtube tube are more likely to rattle. And the Junction Box B. A good trick is to wrap some foam around the junction box.
    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  6. #6
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    Quote Originally Posted by marathonrunner View Post
    Got it, thanks. Does the extra wire inside the frame make noises?
    None that I've ever heard.

  7. #7
    'brifter' is a lame word.
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    Quote Originally Posted by marathonrunner View Post
    Got it, thanks. Does the extra wire inside the frame make noises?
    If it ends up rattling around in the frame you can always put those little things that Shimano makes on the wire. They're sort of like a little zip-tie that keeps the wire from moving around...heck, just try some little zip ties, they'll do the trick. The 'tail' pushes the wire against the frame and keeps it from moving.
    I work for some bike racers
    I've got some bikes, some guns,
    and a bunch of skateboards

  8. #8
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    Quote Originally Posted by cxwrench View Post
    If it ends up rattling around in the frame you can always put those little things that Shimano makes on the wire. They're sort of like a little zip-tie that keeps the wire from moving around...heck, just try some little zip ties, they'll do the trick. The 'tail' pushes the wire against the frame and keeps it from moving.
    You can actually buy those Shimano "zip ties" as a Shimano part. Trouble is, they cost about 100 times as much as a bag of home Depot zip ties, and it's really hard to see the difference.......
    All the internal builds I've done have used the home Depot ones.....
    No complaints so far.

    Sent from my SM-G950W using Tapatalk

  9. #9
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    Quote Originally Posted by cxwrench View Post
    If it ends up rattling around in the frame you can always put those little things that Shimano makes on the wire. They're sort of like a little zip-tie that keeps the wire from moving around...heck, just try some little zip ties, they'll do the trick. The 'tail' pushes the wire against the frame and keeps it from moving.
    Those "zip ties" are convenient, the ends clip onto the wire instead of having to be zipped on. My bike came with them installed.

    The theory is that the loose end of the tie keeps the wire pressed against the tube due to the spring in the tie's tail, which is long enough to touch the other side of the tube.

    But I still got rattling. Only with certain kinds of rough road vibrations.

    I removed the fork to get access to the top of the downtube, and unclipped the original ties.

    I slit some small cubes of foam, which were a little larger than the downtube diameter, put the wire in the center, tied it shut with string. Then slid them down partway into the tube. That fixed it.

  10. #10
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    Quote Originally Posted by Finx View Post
    I use a wire with enough slack to pull the wire off of the battery. I use a rubber band over the outside of the seat tube to keep it from slipping down inside while it's not connected.

    Di2 connector tool


    OP, since you installed the Di2, you already know about the inexpensive plastic Di2 connector tool. It's way easier on the wire connectors, making it less likely to strain or break a wire, and to make sure the connector clicks in when installing.

    It looks like the battery uses the same wire and connectors.

    Tool usage, from the pdf Di2 "Dealer's Manual", worth downloading if you do any work on your Di2 components. It's easy to follow, and very detailed.





    Attachment 322915

    Attachment 322916
    Last edited by rm -rf; 06-13-2018 at 06:35 PM.

  11. #11
    coaster
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    While you're replacing the wire with one that reaches out of the seat tube you could also put the battery in the frame so you don't need to deal with it every time yiu remove the seatpost. Wrap a single layer of bubble wrap around it with some tape over that and drop it down the seat tube.

  12. #12
    tlg
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    Quote Originally Posted by Lelandjt View Post
    While you're replacing the wire with one that reaches out of the seat tube you could also put the battery in the frame so you don't need to deal with it every time yiu remove the seatpost. Wrap a single layer of bubble wrap around it with some tape over that and drop it down the seat tube.
    If you do that, make sure you securely attach a string with a loop on it so you can fish it back out.
    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  13. #13
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    Quote Originally Posted by tlg View Post
    If you do that, make sure you securely attach a string with a loop on it so you can fish it back out.
    Yeah, I think I'll leave it in the seatpost. The Ritchey seatpost container seems to work really well. Also, wouldn't having the battery in the seattube prevent water from draining out the bottom bracket? Water does get between my seatpost and seattube somehow and drains out the bottom bracket...as long as there's no mud blocking the hole in my frame under the bb.


    Oh, and I have and used that connecting tool properly.
    I like to ride fast.

  14. #14
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    Do any di2 A junction mounts exist for the lezyne out front gps mount? I used tiny zipties to attach the A junction box but it's not straight and doesn't look terribly refined. It's better than the stupid strap around the stem though.

    I don't want the A junction box under the stem for multiple reasons.
    I like to ride fast.

  15. #15
    tlg
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    Quote Originally Posted by marathonrunner View Post
    Do any di2 A junction mounts exist for the lezyne out front gps mount? I used tiny zipties to attach the A junction box but it's not straight and doesn't look terribly refined. It's better than the stupid strap around the stem though.

    I don't want the A junction box under the stem for multiple reasons.
    Check out my signature. I make 3D printed junctions box mounts.
    Custom Di2 & Garmin/GoPro mounts

    There isn't a di2 mount for the lezyne. It's not a good option to mount the di2 junction box onto a gps mount. I pushes it too far out beyond the bars and isn't very clean.
    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  16. #16
    coaster
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    Quote Originally Posted by tlg View Post
    If you do that, make sure you securely attach a string with a loop on it so you can fish it back out.
    The J-bend end of a spoke catches on the bubble wrap easily. You don't wrap so many layers around the battery that it's a tight fit (which could trap water and be hard to get out). You give it a single wrap so you don't hear it moving around.

  17. #17
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    Quote Originally Posted by marathonrunner View Post
    Do any di2 A junction mounts exist for the lezyne out front gps mount? I used tiny zipties to attach the A junction box but it's not straight and doesn't look terribly refined. It's better than the stupid strap around the stem though.
    Quote Originally Posted by marathonrunner View Post

    I don't want the A junction box under the stem for multiple reasons.

    This may or may not help. I've used these on a few builds. Better than a strap, but not as nifty as integrated frame or handlebars.

    FOURIERS :: Products

    There are other similar products out there, including some on the shapeways 3D printing site.
    Last edited by Finx; 06-15-2018 at 09:21 AM.

  18. #18
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    Those 3d printed mounts and FOURIERS mounts all go under the stem though.

    I don't have any spacers under my stem, and I like being able to grab the stem to maneuver the bike through the many tight 180 degree turns in my house to get bikes from outside into my basement workshop.

    Shapeways might be able to make one for me.
    I like to ride fast.

  19. #19
    tlg
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    Quote Originally Posted by marathonrunner View Post
    Those 3d printed mounts and FOURIERS mounts all go under the stem though.

    I don't have any spacers under my stem, and I like being able to grab the stem to maneuver the bike through the many tight 180 degree turns in my house to get bikes from outside into my basement workshop.

    Shapeways might be able to make one for me.
    I grab my bike by the stem all the time without problems.

    Shapeways doesn't make anything. They're just a 3D printing service. You need to, or have someone provide the design to print.

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