Modifying the Di2 Sprint Shifter for 10spd

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06SpiceRed
Posts: 33
Joined: Thu May 12, 2011 5:06 am
Location: Boulder, Colorado

by 06SpiceRed

This is a crosspost from BF that I thought I would ask the fine folks in WW world if anyone can shed light on the matter.

While the web is full of useful Di2 information, I have been wondering if anyone has successfully been able to add Di2 Sprint Shifters to 10 Speed Ultegra shifters. It is well known that the sprint shifters have a tab located on the end of the E-tube wire that is specific to 6870 and 9070 due to the third port having an added slot to accomdate it. I know the simple answer would be to go ahead and make the purchase of 6870/9070 shifters and be done with it but I know there are a few 10 speed guys that have wanted this feature without having the need to go an upgrade.

There is one short youtube video where a guy has done that but there are not specifics regarding the hack.

I guess the question comes down to, has anyone filed off the tab and tried it to any affect? Does it simply work that easily and just no one has done it?

Another option would be to hack open the climbing shifters and relocating the buttons on each drop but might not be worth it.
A bunch of carbon, with a bunch of electronic parts

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aaric
Posts: 430
Joined: Thu Jun 09, 2011 4:10 pm

by aaric

The di2 sprint shifters are just momentary switches. I've created functional switches using a cateye remote, and an e-tube cable cut in half, and it works just fine for climbing shifters.

My assumption is that shorting the etube wires out in the normal bus is a bad thing, and that's why the sprint shifters have the extra tab to prevent them from being plugged in. The climbing shifters have more to them which includes a circuit board to interface with the etube bus.

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06SpiceRed
Posts: 33
Joined: Thu May 12, 2011 5:06 am
Location: Boulder, Colorado

by 06SpiceRed

Anyone have any other information to share regarding the topic? One source suggested filing down the tab to make it connect and trying that out. I know my shop has a few bits laying around. Looks like I have a saturday morning project to try out.
A bunch of carbon, with a bunch of electronic parts

glepore
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Joined: Thu Mar 28, 2013 4:42 pm
Location: Virginia USA

by glepore

I have no specific information but there is likely a reason beyond marketing for the tab. It may just not work. It might fry the battery. Batteries aren't cheap.
Cysco Ti custom Campy SR mechanical (6.9);Berk custom (5.6); Serotta Ottrott(6.8) ; Anvil Custom steel Etap;1996 Colnago Technos Record

aaric
Posts: 430
Joined: Thu Jun 09, 2011 4:10 pm

by aaric

There's a bit of information in other threads.

However, given the way a bus works (they are transmitting signals over the two wires in waves or pulses) vs the way the shifter buttons work (closed = shifting), you're not going to have much luck, and have a reasonable likelihood of causing issues with the rest of the system.

I don't think many people are going to file the tab off and try it, because the cost of the sprint shifters is about the same as the cost difference between the 6870 and 6770 levers on the secondary market, and you risk burning out a bunch of di2 parts to test it for a ~$100 savings.

If you want to try it, just grab an e-tube wire (~$20) and cut it in half, then strip the leads. Plug it into your shifter port and briefly touch the bar wires together. I'd wager nothing happens, as the control units are expecting encoded signals. You'll probably not damage anything either, but the likelihood of damaging something is higher than the likelihood of it working.

other sprint shifter threads for reference:
viewtopic.php?f=3&t=126091

viewtopic.php?f=3&t=125861

viewtopic.php?f=3&t=127909

viewtopic.php?f=3&t=127059

glepore
Posts: 1408
Joined: Thu Mar 28, 2013 4:42 pm
Location: Virginia USA

by glepore

A 6870 right body is the same price as a climbing shifter pod, so you could buy that and whatever momentary switches you wanted, along with the appropriate etube cable and have switches wherever you want, hence no need to hack the climbing shifter. Or, you could, for the same cost, buy a climbing shifter and solder on wires for additional momentary shifters wherever, and have shifting everywhere.

Its sorta angels on the head of a pin.
Cysco Ti custom Campy SR mechanical (6.9);Berk custom (5.6); Serotta Ottrott(6.8) ; Anvil Custom steel Etap;1996 Colnago Technos Record

grouk
Posts: 232
Joined: Wed Sep 17, 2014 5:29 pm

by grouk

i have di2 6870 and i have home made sprinter switch and climb switch, so simple like that, two momentary switchs pluged in paralel one di2 cable cut in half pluged in the tab port. configure etube and it is done. i have in my aero bars switchs too. the port with tab in the shifters are without need of PCB conection so you could plug any switch that you whant

Jesper64
Posts: 71
Joined: Sat Aug 30, 2008 1:16 pm

by Jesper64

The spare port on the 6770 shifter is essentially a junction box so to pass any meaningful information through it whatever you connect needs to have some circuitry to communicate on the eBus system eg climber switch, diagnostic tool. Whereas on 6870/9070 there is an additional 3rd port which is notched for the sprint shifters, which as people have said are just momentary switches. The momentary switch closes and that triggers something in the brains of the 6870/9070 shifter body itself which then sends a shift signal out.

You could test to be double sure. As suggested above use an etube wire and plug it in, but you don't need to ruin one by cutting it in half, just use something thin to short across the open end.

by Weenie


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