Weight Weenies

I've been interested in the idea of putting sprint shifters on my bike, but the are overpriced. So after dong some reading, it turns out they are just momentary switches attached to half a standard e-tube wire with a notch on the plug so that in can only be put into the dedicated port. Also because of this notch you can only have one pair of shifters.

So this got me thinking, how hard can it be to make my own shifters? So I purchased an e-tube wire (needs to be >600mm) and some momentary switches (circuit diagram too). By using a switch with 4 connection points, I was able to put 2 switches in parrallel to give me 2 pairs of sprint shifters (which I put on my tops and drops).





First I cut the end, plus enough cable, off the e-tube wire and stripped it to the wires. Inside there are just 2 wires, one red, one black. Since we are just completing the circuit these colours are irrelevant.



Since I don't have access to a soldering iron (apartment problems) I crimped one terminal of the switch to each of the wires (though this would be so much easier using solder than crimps)



I then insulated the crimps in electectrical tape and did the same on the other side, with a section from the centre of the e-tube wire, (only showing one terminal crimped).



For the second switch, since this would be at the end, I broke off one pair of terminals to prevent the circuit shorting and joined the wire to remaining pair of terminals.



This was repeated so I had a pair of the cables and buttons



I connected the wire to the lower Di2 port on my shifter (this has the notch to allow shimano's sprint shifter to be plugged in). then with double sided tape I placed the first button to my desired position on the drops and the second button under the tops.





Then wrapping the bars (bit trickier with the buttons so I'm afraid it is not perfect) and cutting a small section for the buttons.





And voila, 2 pairs of sprint shifters that work. Overall the parts cost < £20 compared to shimano's version which retails at £100 (although can be found for closer to £75).

Nice work. Is the button waterproof? I would throw some hot glue or epoxy over your connections to seal those from sweat and rain.

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I've been doing this with cateye remote switches...roughly $9 for the pair from performance (http://www.performancebike.com/bikes/Pr ... 83__400283). I looked for a bit to try to find a good source of waterproof switches and kept coming back to using the cateye ones.

+1 for the cateye switches. That's what I used also.

Lol. I'm sure cateye sells more of those buttons for di2 than for their intended purpose.

This only works with 9070 and 6870 shifters, right?

It won't work with the 6770 shifters, as they don't have the extra shifter port. I have no clue about the non e-tube 7970 stuff, but assume not.

+ Cateye.

Nice work!

The 7970 are just easier. You solder the buttons in parallel with the shifter harness. This has been done many times. I've got that on my 2006 R3. I use a pair for each derailleur. You can search ww for this mod including wiring diagrams.

7970 does have 1 extra port for either climber or shifter.

To have both, you need to splice.

I've done a DIY on 7970 using Shimano's own Climber and shifter buttons, as I'm sure a good few have too.

Cateye switches may be a good cheap alternative, but the mini-lever which cover the actual switches on the shimano sprinter switches is what makes them special exactly suited to the job in hand.

You are not so much thinking about clicking a button to change, just a flick of the thumb in the general direction of that lever makes the lever click the button underneath and gets the job done. When on the drops, out the saddle thats about all the focus I want to give to a gear change.

Quick report: It has all been working very nicely, not having to move hands for shifting is very nice. I've had a couple of rides in the rain with no issues, but I may put a small piece of cling-film or similar over the buttons when I next wrap my bars, just to be sure. The buttons only need a small depression to shift (~1mm maybe) so in the drops a small brush is all that's needed, I didn't have to think about it anymore after a couple of rides.

I did consider the cateye buttons but they were a bit more expensive (these buttons cost under £3 for 10) and would have required a bit more splicing to get 2 sets of extra shifters which I wasn't as happy to be doing.

i use that setup a year a go, first i use a normal switch buy at local eletronic shop, first time in the rain start failure
then i buy a better switchs and i put it inside a round plastic piece, like that i can put tape above the switch, with the tape it becomes waterproof.

for the climbing switchs i use a flat membrane switch,now my setup is perfect and i love it

So, I thought that connecting a normal switch alone to Shimano's e-tube products (6770, 6870, 9070) would not work because of the protocol that is now used in all of the shifters. Is there a way around this other than buying Shimano's sprint or climbing shifter and opening it up to solder wires directly into the circuitry?

There's a dedicated sprint shifter port on the 6870 and 9070 levers that you can just use an e-tube wire to connect to.


The sprint shifters plug in here, and contain no circuitry.

Oh, I see now. I was trying to do this on my 6770 shifters and it was not working. I plugged my wire into my brother's 6870 shifter and voila, it works. So, now it looks like I need to do a shifter upgrade or live with 6770 limitations.

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