Author Topic: Electronic Gears for tandems.  (Read 5750 times)

Electronic Gears for tandems.
« on: 11 May, 2015, 06:37:28 pm »
 My Raynauds makes life difficult for me when it is cold and especially when it is cold and wet. On a recent 200k I could not change my STI gears as my hands were too cold to work properly especially with my right hand. I noticed a few riders this weekend on bikes with electronic shifters which only require a thumb movement. Has anyone any experience with the Shimano electronic system on tandems? Battery life does not seem to be a problem but the distance from front to rear may be a factor with wireless systems.

LittleWheelsandBig

  • Whimsy Rider
Re: Electronic Gears for tandems.
« Reply #1 on: 11 May, 2015, 07:07:57 pm »
The Things have been using electronic shifting on their go faster tandem for the past year.
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Re: Electronic Gears for tandems.
« Reply #2 on: 11 May, 2015, 07:09:09 pm »
Wireless?

I assume you mean cableless.

Agreed that getting the length of wire required might be a challenge, but I doubt that electrical losses (resistance) would be that great to cause a problem.

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Dibdib

  • Fat'n'slow
Re: Electronic Gears for tandems.
« Reply #3 on: 11 May, 2015, 07:53:01 pm »
Wireless?

I assume you mean cableless.

SRAM apparently have a wireless groupset in development, but for the moment I think it's a bit secret-squirrel-pro-teams-only.

Common-or-garden Shimano or Campag electronic groupsets should be fine, but depending on what you're thinking of running, be mindful that Shimano road and Shimano MTB electronic groupsets apparently aren't compatible with each other.

thing1

  • aka Joth
    • TandemThings
Re: Electronic Gears for tandems.
« Reply #4 on: 11 May, 2015, 08:25:47 pm »
Yep we did 2x 1200km brevets last year with Di2 on the Tandem. I love it. Shifting is less tiring and having multiple gear shift positions is fantastic. I have STIs and also aerobars and climbing shifters for the rear derailleur.

Road groupo does limit you to a double and just 32T at the back. XTR solves that but as said  above you can't mix XTR rear derailleur with road front derailleur - at least not until someone works out how to hack the firmware to remove that artificial limitation. You can use road levers with MTB derailleur fine though so long as both derailleurs are MTB style.

If you have more questions fire away. :)

Re: Electronic Gears for tandems.
« Reply #5 on: 12 May, 2015, 08:47:02 am »
There is also an electric shifter for Rohloffs:

http://www.edsanautomation.com.au/EdsanProducts.htm

We have never tested a Rohloff on our tandem, let alone an electric Rohloff, but are seriously thinking about that.

Re: Electronic Gears for tandems.
« Reply #6 on: 12 May, 2015, 06:27:41 pm »
Thanks for the information. I had forgotten about the road sets being for double only. Would we need a triple for PBP? We are reasonably fit for old gits and got up the hills at the end of Asparagus and Strawberries without using the granny ring and on 32 bottom cog without struggling. Maybe we should just wait until someone develops a set for triples.

Biggsy

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Re: Electronic Gears for tandems.
« Reply #7 on: 12 May, 2015, 06:49:51 pm »
How about using the electronics just for the rear gears and an old fashioned friction lever for the front (perhaps a thumb one)?  Easier than STI?
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Re: Electronic Gears for tandems.
« Reply #8 on: 12 May, 2015, 08:27:02 pm »
I can't imagine you'd need a triple on PBP. We never trouble the granny in easy anglia (except Hartest Hill) either.
I don't remember much out of the big ring on PBP, though I am a monster masher.

Re: Electronic Gears for tandems.
« Reply #9 on: 12 May, 2015, 09:02:55 pm »
I can't imagine you'd need a triple on PBP. We never trouble the granny in easy anglia (except Hartest Hill) either.
I don't remember much out of the big ring on PBP, though I am a monster masher.

I wouldn't have thought so either.

However - last year on the way out to Mortagne, I fixed an Indian lad's bike - the front mech clamp had broken, and I took the mech off for him, but when I lifted the chain into the middle ring, he was adamant that he needed it in the granny ring. He was from Bangalore, I don't know how hilly it is around there.

It can't have been a quick ride to Mortagne, as he'd just arrived when I was leaving.

Re: Electronic Gears for tandems.
« Reply #10 on: 13 May, 2015, 01:37:37 am »
We were a little concerned about the lack of triple before we got the bike, but haven't been defeated by the lack of granny so far. The combination of electronic shifting and SRAM red 22 chainrings means we run 52-33 on the front and 11-32 on the back without any problems and all 22 gears are accessible. Most mechanics refuse to believe that set up works though......
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clarion

  • Tyke
Re: Electronic Gears for tandems.
« Reply #11 on: 13 May, 2015, 09:00:29 am »
Tandem seems an obvious candidate for electronic shifting.  Long gear cables can mean there are delays in changing and remote feeling.   
Getting there...

Re: Electronic Gears for tandems.
« Reply #12 on: 13 May, 2015, 10:46:57 am »
And it is surely only a matter of time before someone starts to think about two way switches...  ;D

tiermat

  • According to Jane, I'm a Unisex SpaceAdmin
Re: Electronic Gears for tandems.
« Reply #13 on: 13 May, 2015, 10:49:35 am »
How about using the electronics just for the rear gears and an old fashioned friction lever for the front (perhaps a thumb one)?  Easier than STI?

Won't work with DA/Ultegra, as the system needs to detect there is a front mech there before it will inialise.

However, the XTR one is available in 1*11, so presumably it will work without a front mech (or uses a dummy mech to confuse the system into working)
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Morat

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Re: Electronic Gears for tandems.
« Reply #14 on: 14 May, 2015, 03:16:30 pm »
And it is surely only a matter of time before someone starts to think about two way switches...  ;D

As a stoker, I second the motion! :)
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thing1

  • aka Joth
    • TandemThings
Re: Electronic Gears for tandems.
« Reply #15 on: 27 May, 2015, 08:10:55 pm »
And it is surely only a matter of time before someone starts to think about two way switches...  ;D

I generally have 3 sets of RD shifters up front - STI, aerobar and climbing shifter. Another nice benefit of electronic groupo for long rides (and god knows I'll miss the aero extension shifters on pbp. Typical that tandems are penalized just because half bikes can't play nicely together :-P )

Yeah the conversation has come up in jest of moving one set of shidters back, but I don't think either of would really enjoy that though.

Karla

  • car(e) free
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Re: Electronic Gears for tandems.
« Reply #16 on: 27 May, 2015, 08:17:06 pm »
How about using the electronics just for the rear gears and an old fashioned friction lever for the front (perhaps a thumb one)?  Easier than STI?

Won't work with DA/Ultegra, as the system needs to detect there is a front mech there before it will inialise [sic  :P ].

Yebbut how hard is it to spoof?

Re: Electronic Gears for tandems.
« Reply #17 on: 27 May, 2015, 11:35:00 pm »
And it is surely only a matter of time before someone starts to think about two way switches...  ;D

I generally have 3 sets of RD shifters up front - STI, aerobar and climbing shifter. Another nice benefit of electronic groupo for long rides (and god knows I'll miss the aero extension shifters on pbp. Typical that tandems are penalized just because half bikes can't play nicely together :-P )

Yeah the conversation has come up in jest of moving one set of shidters back, but I don't think either of would really enjoy that though.
We've seriously considered a second tandem with the gears on the back, racing style. Shorter cable runs, give me something to do, and he often wants a break from it by the end of a long ride. It'd be a big tick in favour of electrics for us.

Biggsy

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Re: Electronic Gears for tandems.
« Reply #18 on: 28 May, 2015, 04:09:25 pm »
Hopefully, you could have the front mech fitted as a dummy above your functioning mech, if it's too tricky to spoof electronically.  Would be nice if it was as simple as closing a circuit, but things don't tend to be that simple these days.
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thing1

  • aka Joth
    • TandemThings
Re: Electronic Gears for tandems.
« Reply #19 on: 29 May, 2015, 05:38:25 am »
Using a friction shifter for the FD would also remove one of the nice benefits of electronic shifting: the auto-trim function on the FD.

The XTR triple FD is little use though, it has a maximum chainring size of 40T (I finally found this in http://www.starbike.com/manuals/shimano-xtr-di2-m9050-dealers-manual-en.pdf) and the XTR double even worse at 38T max chainring.


Damn shame. If they just allowed an ultegra FD and XTR RD work together you could if needed use a 10-42T SRAM cassette for 52/10 top and 33/42 bottom gear and lack of triple wouldn't be an issue at all.....  :-\

thing1

  • aka Joth
    • TandemThings
Re: Electronic Gears for tandems.
« Reply #20 on: 29 May, 2015, 05:44:26 am »
We've seriously considered a second tandem with the gears on the back, racing style. Shorter cable runs, give me something to do, and he often wants a break from it by the end of a long ride. It'd be a big tick in favour of electrics for us.

Yeah basically I found that electronic shifting solved these issues anyway.... cable run length becomes a non-issue, and the climb shifter removed a good chunk of the annoyance I had with shifting on day 3 of a 1200kms. (basically, I have times when I just want to sit upright, and on rolling terrain keeping on reaching for the STIs is tedious but not necessary with the climb shifter).


We should try out devolving control one day though...

Re: Electronic Gears for tandems.
« Reply #21 on: 29 May, 2015, 08:20:58 am »
We've seriously considered a second tandem with the gears on the back, racing style. Shorter cable runs, give me something to do, and he often wants a break from it by the end of a long ride. It'd be a big tick in favour of electrics for us.

Yeah basically I found that electronic shifting solved these issues anyway.... cable run length becomes a non-issue, and the climb shifter removed a good chunk of the annoyance I had with shifting on day 3 of a 1200kms. (basically, I have times when I just want to sit upright, and on rolling terrain keeping on reaching for the STIs is tedious but not necessary with the climb shifter).


We should try out devolving control one day though...
I don't think it's a physical tiredness. I come properly into my own at the end of rides, whereas he fades a bit. Sometimes he's too tired to pick the right gear and I end up calling them all... Maybe I'm just fussier! Because we're mashers rather than spinners I wonder if we'd get away with a double... *daydreams*

tiermat

  • According to Jane, I'm a Unisex SpaceAdmin
Re: Electronic Gears for tandems.
« Reply #22 on: 29 May, 2015, 08:22:11 am »
Looking through various online articles, it appears that it must be possible to use Ultegra Di2 with a single front ring, as many CX racers are using just that setup (at least at pro level).  Why is this relevant? Well using a single ring, or using a manual front changer is, to a Di2 system, exactly the same thing.

I have been unable to find anything about how to do it, though, maybe dropping an email to Lennard Zinn, over at Velonews, might get an answer (from reading a few of his articles it appears he runs such a setup on [on of] his CX bike)
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thing1

  • aka Joth
    • TandemThings
Re: Electronic Gears for tandems.
« Reply #23 on: 09 June, 2015, 06:30:54 am »
I just stumbled across my very own notes on the subject: http://blog.tandemthings.com/2015/01/xtr-di2-parts-on-road-tandem.html

Yes, with only the RD connected the Dura-Ace lever would shift the XTR RD just fine. It's only when I connected the (Ultegra) FD that the system halted.
This does open the possibility of a glorious hack of running 2 independent Di2 buses: one for front and one for rear. Would require 2 batteries and again looses the auto-trim feature.