XTR di2 1x11 parts ?

mattjevans
mattjevans Posts: 253
edited February 2015 in MTB workshop & tech
Playing with the idea of putting 1x11 di2 on my next bike. Will be using SRAM cranks with direct mount chainring and 10-42 cassette (compatible according to Fairwheel bikes). Already have brakes so I am only asking about the mech/shifter components for pure 1x.

Might be pointless but looking to understand what's required. Given how new this group is there may not be answers to my query but anyway...
Now I know I need:
one of these, obviously http://www.ridextr.com/en/productdetail ... M9050.html
and a right one of these http://www.ridextr.com/en/productdetail ... M9050.html
SMBTR2 battery, which i'd install in steerer tube using one of these http://www.madison.co.uk/products/cycli ... r-sm-btr2/
And obviously 2 or 3 sd50 e-tube wires.

Question is do I need this: http://www.ridextr.com/en/productdetail ... M9050.html
or could I use one of these instead http://www.artscyclery.com/Shimano_EW90 ... EJB90.html



Is any sort of Junction B box required?

Comments

  • The Northern Monkey
    The Northern Monkey Posts: 19,174
    http://www.chainreactioncycles.com/shim ... prod127994
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  • mattjevans
    mattjevans Posts: 253
    Um that's a triple group, and I don't need new cranks or a Shimano cassette

    It turns out from further research that display unit isn't needed for 1x, but I still not sure what minimum di2 junction box is needed
  • oodboo
    oodboo Posts: 2,171
    The display might not be required but it does show the battery level. Can you do without that? I wouldn't fancy get stuck in one gear half way round a ride because I didn't know the battery was low.
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  • mattjevans
    mattjevans Posts: 253
    If you do without display, as I understand it you still need a Junction A box which has a battery charge indicator light on it.

    Both the display and the smaller Junction A box have three ports, one thing I don't know is if the battery can be plugged directly into one of them
  • njee20
    njee20 Posts: 9,613
    The battery lasts thousands of miles, and the front mech has a significantly bigger current drain than the rear, so on a 1x11 it should last even longer. Plus you've got the warning light on the junction box. A complete non issue.

    As you say - you certainly can do without the display, but you'll need a junction box. The 3 way one will be fine if you just want the one shifter, indeed it should actually have a spare port (as it's designed for two road shifters). The 5-way one would mean you could fit ancillary shifters if you wanted, although not sure where you'd put them on a mountain bike!
  • njee20
    njee20 Posts: 9,613
    As an aside...I looked at it, but it's heavier than mechanical with a single ring set up, and the front mech action and the sequential shifting are the really cool bits. So I decided it's not worth it with a single ring.
  • mattjevans
    mattjevans Posts: 253
    njee20 wrote:
    The 3 way one will be fine if you just want the one shifter, indeed it should actually have a spare port (as it's designed for two road shifters). !

    I thought I'd plug shifter, rear mech and battery into the 3 port junction box?
  • jimothy78
    jimothy78 Posts: 1,407
    njee20 wrote:
    As an aside...I looked at it, but it's heavier than mechanical with a single ring set up, and the front mech action and the sequential shifting are the really cool bits. So I decided it's not worth it with a single ring.

    I was just about to post the same thing - why does the OP want electric shifting for a 1x setup? To my mind that makes it utterly pointless - without the integrated front/rear shifting pattern, you're just lugging around a battery for no real benefit.
  • njee20
    njee20 Posts: 9,613
    mattjevans wrote:
    njee20 wrote:
    The 3 way one will be fine if you just want the one shifter, indeed it should actually have a spare port (as it's designed for two road shifters). !

    I thought I'd plug shifter, rear mech and battery into the 3 port junction box?

    Nah, mechs plug into battery, you plug battery and shifters into the junction box.
  • mattjevans
    mattjevans Posts: 253
    edited February 2015
    jimothy78 wrote:

    I was just about to post the same thing - why does the OP want electric shifting for a 1x setup? To my mind that makes it utterly pointless - without the integrated front/rear shifting pattern, you're just lugging around a battery for no real benefit.

    it's the bling, innit...

    I fully accept this may well be madness - keeping my current cranks and upgrading to mechanical XTR (leaving aside cost of cassette which is the same with an X1 cassette would cost c.£200. The same with di2, over £600.
  • mattjevans
    mattjevans Posts: 253
    njee20 wrote:
    Nah, mechs plug into battery, you plug battery and shifters into the junction box.

    Confused... For some reason I thought with this new e-tube setup as long as everything was plugged into some junction it didn't really matter what went where. I was planning to do a steerer tube battery with junction A on the downtube, which would make for quite tidy wiring - just one wire each running from shifter and battery, and then one down to the mech. If this turns out to need two junction boxes I'll scrap it
  • njee20
    njee20 Posts: 9,613
    Should work...
  • mattjevans
    mattjevans Posts: 253
    njee20 wrote:
    Should work...

    Yep, but I'm kind of hoping for a more definitive "yes, that works I've done it"...
  • cooldad
    cooldad Posts: 32,599
    mattjevans wrote:
    njee20 wrote:
    Should work...

    Yep, but I'm kind of hoping for a more definitive "yes, that works I've done it"...

    I doubt many people would even consider it at this point, let alone do it.
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  • mattjevans
    mattjevans Posts: 253
    cooldad wrote:

    I doubt many people would even consider it at this point, let alone do it.

    Probably not for XTR but a Dura-ace or Ultegra 1x CX setup shouldn't be any different and there's any number of those around
  • njee20
    njee20 Posts: 9,613
    Most are still using both STIs though. I think my concern would be the diagnostics - you have to unplug something, with two shifters you unplug one of those, then swap it, but I don't know if that would matter more with three key parts of the system.

    Why is the lower junction box such an issue?
  • The Rookie
    The Rookie Posts: 27,812
    You're more likely to get a definitive reply on the WW website where I see you have posted the same question, the was a recent post where someone was using an Ultegra Di2 on an MTB but I can't find it right now, will get it tomorrow when I have the laptop and post a link for you.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • mattjevans
    mattjevans Posts: 253
    Yeah got the answer on WW, thx
  • mattjevans
    mattjevans Posts: 253
    In any case, good sense prevailed and I ordered mechanical
  • njee20
    njee20 Posts: 9,613
    And the answer was...?

    Wise choice. Di2 for 2x11.

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