On the P3 you can not insert the the internal junction box in through the bottom bracket opening. It is just too small. So I ran all my wires up the seat tube where I could plug them into the internal junction box with the seat taken out and then simply dropped the plugged wires and internal junction box back down into the seat tube. Fishing the wires was not too difficult. I used dental floss with a small nut tied to it and also a wire coat hanger to get the pull strings in place.

I went with the internal Dura Ace battery inside the seat post. It is a tight fight so there is no movement.

So I have a fully internally wired Di2 system with both sets of shifters. Used the bike in a Half last month and an Olympic Race last weekend and it performed beautifully both times.

I really like the setup and can never see me going back to manual shifting. Good luck and let me know if you have other questions.

Thanks for reply. So you end up using pretty long wires in order to get all 4 connected in seat tube, right? Did you have to splice and solder the from front and rear derailleur? What about from the front? Thanks

zigor911 wrote:

Thanks for reply. So you end up using pretty long wires in order to get all 4 connected in seat tube, right? Did you have to splice and solder the from front and rear derailleur? What about from the front? Thanks

Yes I went with longer wires to allow me to snake from the shifter junction box down to the bottom bracket and back up to the top of seat post opening. Same thing from derailleurs to the top of the seat post opening. Shimano sells the wires in lengths long enough to make it. So I do not have any spliced wires.


You can estimate the lengths you need using string or a tape measure.

Thanks! Surprised you were able to get wires through the frame w/o splicing - it seams all other posts suggested that as holes in frame were not big enough. Did you have to enlarge/ drill them out a bit?

zigor911 wrote:

Thanks! Surprised you were able to get wires through the frame w/o splicing - it seams all other posts suggested that as holes in frame were not big enough. Did you have to enlarge/ drill them out a bit?

Yes I enlarged the holes a little bit. I believe I was able to use a 7/32 bit which is close to the 5mm diameter of the wire ends. On the top of the bike for the shifter junction wire I went through the side cable opening on the top end of the down tube. For the front derailleur I went through the cable opening near the FD at the bottom of the seat tube. Finally for the rear derailleur I went through the opening at the rear of the chain stay.


Clean, simple and worked like a charm.

Did you take any pics of the internal battery setup inside your seat post? How do you keep it from dropping out of the seat post?

i'm not a P3 owner but am very experienced with di2 installations.

if you have any closed-cell foam, give the battery a few wraps of it and then slide it in the post. you'll have to experiment a touch. i find that a spiral wrap (think how you wrap a handlebar) works well where the upper-most part is a 1/2 or single layer of the foam and then there is some overlap as you go down toward the bottom.

this facilitates stuffing the assembly into the post.

it can still be removed with some force but if done correctly there should be no way for it to accidentally slip.

hope this helps.

Thanks! And does the standard di2 internal battery fit in the new P3 seat post?

it's about 16mm diameter. i suggest measuring the inside of your seat post to be sure.

alternately, you could put it in the seat tube if you just need a few more mm of clearance.

fits inside a shiv TT's post.

^

I have the new P3 (48cm) and the standard di2 internal battery fits. Just need to secure it in the seat-post like wrapping with foam or place it in the seat tube with foam/protection so it doesn't move around.

Just to be clear, we're all talking about this product, correct?


Shimano BTR2 Di2 Internal Battery E-tube

Yes. Since I'm still waiting on a few parts and haven't put my bike together yet here is a picture I just took for you:



edit: also have a look at this thread from Brad: http://forum.slowtwitch.com/gforum.cgi?post=5079478

Would the seatpost not be a preferable position for the battery in case so you need to remove the seatpost for travel, etc...? Or would it just be banging around in there?

Do you mean the seat tube? In either case you want to secure the battery so it doesn't move about/rattle/hit against the frame and potentially cause a catastrophic failure/ frame damage. Others have installed it in the seat tube so the seat post can be removed (e.g. for travel). If you get a long enough di2 cable from the battery to the junction box you can remove the seatpost from the bike and disconnect the cable to the battery for travel. I think I misjudged for my cable so to remove the seatpost I will need first disconnect from under the bottom bracket first.

Hi, yes, sorry - meant in the seat tube, not seat post, as you say. I've seen airforce brads thread. Are there pics floating around of a seat tube instalation?

I've got the frame, just waiting on all the bits to arrive and my LBS has a bunch of cables in stock as they specialise in builds.
Thanks!

it feels like the seat post is the same as the P3 2016, so the internal battery would fit there. Am I right?

I've got a 2014 Cervelo P2, which should be the same seatpost as the 2016 P3. My Di2 battery fits fine inside. I wrapped it with some spongy packing material and electrical tape to keep it secure and from rattling.

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