Where do you mount your Di2 Junction box?

JesseD

At present I have a Lightweight Di2 junction box spacer (one of these https://www.bike24.com/p2127195.html) as well as a 10mm headset top cap, this is coupled with a -6 degree stem, however I want to lower my bars by 5mm and the easiest way to do this is to lose the 6mm Di2 spacer, however this leaves me with an issue with where to mount the junction box.

I have contacted Kuota UK to see about a 5mm or a flat top cap for my headset but apparently they dont make them, so the logical thing is to lose the 6mm spacer.

I do not like the rubber band idea that Shimano supply, kind of looks messy and an after thought, the bar end junction boxes that have been released look good but will mean a change of bar and stem for me to accommodate and i like th shape of my bars, also have seen that Specialized do a mount that works with their SWorks SL stem which looks good and could be a possibility, and finally Tate Laps do a mount on the bottom of their Garmin mount which also looks ok,

However I am keen to see what ingenious solutions other have found to mount the junction box as I am sure there are better options out there.

ryan_w-2

Di2 junction boxes are soooooo 2016.

All about handlebar / bar-end ports now.

ATYapton

I assume you need to access the junction box the charge the battery? If so you are limited to mounting externally unless to get one of the bar end units. There are some options to mount on the underside of a Garmin mount, barfly are an example.
Other options such as putting the junction in the handlebar would be an option if you’re handy with a soldering iron. But then you’d lose access to the button to program or be able to see the led’s to check on the charge.

JesseD

Ryan_W wrote:

Di2 junction boxes are soooooo 2016.

All about handlebar / bar-end ports now.

I know, looks so much cleaner.

Only problem is I would need to change the bars and stem as well and Zipp dont do compatible bits to allow me to go all internal.

Still could always get out the drill :?

topgunsteve

Depending on your set-up you can hide the 3-port J-box under you're seat, you'll need to be able to run a wire down the seat post - an internal battery may cause a problem here.

At the front end you could use the new wiring yoke to connect the two sifters and connect to the down-tube cable. The 3-port j-box can go anywhere in the system.

JesseD

topgunsteve wrote:

Depending on your set-up you can hide the 3-port J-box under you're seat, you'll need to be able to run a wire down the seat post - an internal battery may cause a problem here.

At the front end you could use the new wiring yoke to connect the two sifters and connect to the down-tube cable. The 3-port j-box can go anywhere in the system.

Whats a wiring yoke?

Quite like the idea of hiding the port under the saddle, and I have an aero seatpost so there would be room despite the battery being held in the post as well, only issue I would have is there are no hole to feed the wires into in the seatpost at all, its all carbon with a round compression clamp which is a pain to use!

Basically this one.

https://shop.ccm-sport.de/artikel,ccm,e ... nte=751819

Pulsatingstar

I just mount mine in the normal place using a double sided sticky pad rather than Shimanos band

pippi_langsamer-2

Pulsatingstar wrote:

I just mount mine in the normal place using a double sided sticky pad rather than Shimanos band

This :idea:

topgunsteve

JesseD wrote:

topgunsteve wrote:

Depending on your set-up you can hide the 3-port J-box under you're seat, you'll need to be able to run a wire down the seat post - an internal battery may cause a problem here.

At the front end you could use the new wiring yoke to connect the two sifters and connect to the down-tube cable. The 3-port j-box can go anywhere in the system.

Whats a wiring yoke?

Quite like the idea of hiding the port under the saddle, and I have an aero seatpost so there would be room despite the battery being held in the post as well, only issue I would have is there are no hole to feed the wires into in the seatpost at all, its all carbon with a round compression clamp which is a pain to use!

Basically this one.

https://shop.ccm-sport.de/artikel,ccm,e ... nte=751819

Sorry, I meant the y-splitter thing.

Check you're seat post, some have access at the top. bear in mind that you'll have a wire from the battery to the junction box and then one from the junction box down to the BB to junction box for the mechs and controls.

Personally I'd keep it simple and go with the aforementioned sticky pad - I'll be using this approach on my TT bike but stuck to the aero bar extension.

topgunsteve

JesseD wrote:

topgunsteve wrote:

Depending on your set-up you can hide the 3-port J-box under you're seat, you'll need to be able to run a wire down the seat post - an internal battery may cause a problem here.

At the front end you could use the new wiring yoke to connect the two sifters and connect to the down-tube cable. The 3-port j-box can go anywhere in the system.

Whats a wiring yoke?

Quite like the idea of hiding the port under the saddle, and I have an aero seatpost so there would be room despite the battery being held in the post as well, only issue I would have is there are no hole to feed the wires into in the seatpost at all, its all carbon with a round compression clamp which is a pain to use!

Basically this one.

https://shop.ccm-sport.de/artikel,ccm,e ... nte=751819

Sorry, I meant the y-splitter thing.

Check your seat post, some have access at the top. bear in mind that you'll have a wire from the battery to the junction box and then one from the junction box down to the BB to junction box for the mechs and controls.

Personally I'd keep it simple and go with the aforementioned sticky pad - I'll be using this approach on my TT bike but stuck to the aero bar extension.

pilot_pete

Regarding the Y splitter, it is actually cheaper to connect the shifters together with one standard cable and then run another from one shifter to the junction A (if you have the newer shifters with two ports).

If you have the stem mount junction A, stick the mount on the underside of the stem and then fit the box to it - much neater than the fugly strap. I personally use black Sugru which is pliable, super strong setting rubber. Beauty of this is you can stick a blob on the mount, push it into position and then clean the excess off to make an incredibly neat finish and a great bond which won't fail with time/ water etc. If you want to remove it you can get it apart and the remnants rub off easily - no sticky residue which takes all day to get off!

You could hide it under the saddle, I have also seen a picture of one tucked up at the base of the seat tube, butted up to the front derailleur (not sure about that myself) and the wire entered through the FD hole, I guess with the can-bus system they just use another junction B somewhere in the frame and run one cable up to the handlebars into one shifter and then one between the shifters.

PP

JesseD

Want to make this as cheap as possible so new cabling etc is probably going to be cost prohibitive, although I agree it will be the neatest solution.

I do like the idea of the Sugru Pilot Pete, can you confirm that there are no issues with the junction box coming lose? I have never heard of the stuff let alone used it but a quick google seems like it could solve a lot of issues if it works as advertised.

The end goal here is to drop 5mm from my stack height so I think the best options for me are as below;

Cheap option 1 - https://www.amazon.com/Rec-mounts-Shima ... B00M2JBEKW
Stick this to the underside of the stem with Sugru and mount the junction box to it

Cheap Option 2 - http://www.mcconveycycles.com/10790/pro ... -stem.aspx
Will hopefully work with me Zipp stem but if not then I can possibly trim to fit.

Not so cheap option - https://www.lordgunbicycles.co.uk/bar-f ... bike-mount
Will hold my Garmin and the Di2 junction box in front of the stem.

Bit more expensive option 1
http://www.mcconveycycles.com/10790/pro ... -stem.aspx
+
https://www.sigmasport.co.uk/item/Speci ... lsrc=aw.ds
This will be around £90 but looks clean, but I would also need to change to Spesh bars as I like bars and stem to match and there are no Spesh bars I like.

Bit more expensive option 2
https://www.merlincycles.com/deda-super ... gJZQ_D_BwE
+
https://www.ribblecycles.co.uk/deda-di2 ... zero-stem/
But as above I would need to also change to Deda bars to match stem which would be another fifty odd quid.

I am leaning more towards option 2 at the moment as it will be cheap to try and looking at the shape of my stem and the s-works stem they seem very similar so it could work with minimum faffing. Failing that I am going to go for the Sugru option and see how long it lasts.

pippi_langsamer-2

The 3m double sided sticky pads i use are good for about 7kg I think, so it's still your cheapest option (cheaper than Sugo).

pilot_pete

Pippi Langsamer wrote:

The 3m double sided sticky pads i use are good for about 7kg I think, so it's still your cheapest option (cheaper than Sugo).

Maybe cheaper, are they neater? I've never used them so can't compare directly.

The Sugru is incredibly neat (you basically can't see it if you put just enough on and clean up all the edges with a suitable sharp edge). You can actually smooth the finish with water too if you wish.

If you apply the Sugru to the Junction A mount, position it correctly and square on your stem (easier if you remove the stem and turn it over on a table), leave it to cure fully, then you can slide the Junction A onto the mount. The mount will be held VERY securely and the junction box will not come loose - let's face it, it weighs nothing. Mine has been attached for 2 years now and shows no sign of coming loose. It has been ridden in the rain and washed numerous times.

I have used Sugru to make a cable grommet and also a hole plug. You could use it to do lots of things - I am considering making an aero seat post light holder to do away with the ugly rubber band.

PP

pilot_pete

Jesse

That Rec mount (first one in your post) is chunky and unnecessary, the junction A comes with a small mount that fits flush to your stem. The box clips in and out of that mount, so all you have to do is stick the mount to your stem. Also, in the pictures accompanying it they have mounted it 'out front' with the cables facing back over. Again this looks a messy solution.
A better solution is having the cables come out from under your bar tape and turning back over under your stem to enter the junction box with the sockets facing forward. The cable that enters your frame (if the entry hole is on the downtube just below and behind the head tube) can be neatly routed from the junction A, with a loop around to the entry hole. To tidy it, use spiral wrap or heat shrink to hold it flush with your rear brake cable for part of the loop. This stops it just being another loose dangling cable.

PP

JesseD

Pilot Pete wrote:

Jesse

That Rec mount (first one in your post) is chunky and unnecessary, the junction A comes with a small mount that fits flush to your stem. The box clips in and out of that mount, so all you have to do is stick the mount to your stem. Also, in the pictures accompanying it they have mounted it 'out front' with the cables facing back over. Again this looks a messy solution.
A better solution is having the cables come out from under your bar tape and turning back over under your stem to enter the junction box with the sockets facing forward. The cable that enters your frame (if the entry hole is on the downtube just below and behind the head tube) can be neatly routed from the junction A, with a loop around to the entry hole. To tidy it, use spiral wrap or heat shrink to hold it flush with your rear brake cable for part of the loop. This stops it just being another loose dangling cable.

PP

Thanks Pilot Pete, I need to dig out the original mount I have with the band on it and have a look at it.

I have a feeling it is a Shimano SM-EW90 Di2 Junction Box Hook so am hoping the hook part can be taken off so its tidy.

pilot_pete

This is a picture of the Junction A mount that comes supplied with the box and strap. https://www.google.co.uk/search?q=Shimano+SM-EW90+Di2+Junction+Box&safe=strict&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj94JD30onYAhVoC8AKHbMMDcYQ_AUIEigC&biw=1024&bih=671#imgrc=lrV18OTNKEouwM:&isa=y

It is really small and may already be attached to the box itself. There is a tiny tag which unclips it and allows the box to slide out. Remove it and chose where you want to stick it!

PP