Electronic & Hydraulic Shifting (Di2, Ui2, customisations)

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  • I normally can't hear anything over the gabber but the computer seems to have shit itself (see pc tech thread) so no audio this morning.

  • Assuming I buy a hydro/di2 lever set like this:
    https://www.evanscycles.com/shimano-di2-­r785-sti-hydraulic-disc-brake-with-rs805­-flat-mount-calipers-EV253007 £400

    What else do I need to complete the groupset?

    FD: http://www.ribblecycles.co.uk/shimano-ul­tegra-di2-6870-11spd-front-gear/
    RD: http://www.ribblecycles.co.uk/shimano-ul­tegra-di2-6870-11spd-rear-gear/
    Cable set: http://www.ribblecycles.co.uk/shimano-di­2-cableset/
    Junc A: http://www.ribblecycles.co.uk/shimano-di­2-junction-a-sm-ew90-a-3-port/
    Battery: http://www.ribblecycles.co.uk/shimano-di­2-internal-fit-battery-7-4v/

    £454.91 for that lot vs. £700 for a set that has levers I don't need:

    I probably already have a cassette, maybe a chain, might use my spare S-Works or DA cranks (although the rings won't be 11spd - hmm will they work?) and likely have a BB kicking around though might need a different one.

    I can see a junction box in the cable set but presume this is the one for the bottom bracket that goes to the two deraillers and I need to buy Junction A separately for the two shifters?

    What am I missing? Do I need shit like separate internal battery mount? Frame grommets?

    Anywhere UK cheaper than Ribble?

  • Hmmm. you need charger.

    The Junction A seems to be included in the cable set going by the pic.

    The internal battery Mount will depend on Your frame. Foe most round tubed seatposts you can just use some pipe insulation foam around the battery to form a Nice snug fit.

  • I have a charger already. Remember my TT race bike is DA Di2.

    I think that pic shows the BB junction box, no? The code is different in the blurb.

    Ta. I'll leave the battery mount out of it.

  • 10 speed chainrings will work with 11 speed. You'll need Junction A as well as the BB junction box. Frame grommets depend on the frame, and whether generic Shimano ones will work or whether the frame has its own cable management system. Internal battery mount will depend on how you're going to mount the battery, but if it's going inside a round seatpost then yes, probably.

    Worth checking Merlin to see what their prices are for the individual components - I generally find them slightly cheaper than Ribble.

  • Cool, so unless I decide to go to Compact, I can use one of my existing cranksets with this build.

    I'll leave out the grommets - we used silicon on the TT bike - it seals better and is easier enough to remove if needed.

    It is a round seatpost though not sure of existing mounting hardware (if any) so will probably leave it up to @scherrit to pick a solution.

    Hmm, Ribble was always my go to for cheap stuff but I'll have a look at Merlin. Ta

  • Oh, short or medium cage? If I'm running Standard double I'll probably have a cheating climbing cassette fitted but even a short cage will do 28T so I'm not sure if I'll need the Medium. What say you, forum?

  • The pic shows the external battery Mount. Might come With round bits to Mount the internal. But insulation foam will do the job.

    I have a spare cable, and little zip tie Things that stop the internal cables rattling. If you find you need them I can chuck them in the post.

    1 Attachment

    • Di2.JPG
  • Short.

    Works With a 29t too.

    I have 52/36, and use 12-29 on my training Wheels.

  • Yep, my medium cage was a waste on my bike I think, the short cage would have been fine for 11-32

  • I think it has options for external or internal battery so the external stuff is redundant but that's how it comes.

    Cheers, I zoomed in on the pic and it's definitely a Junction A. It didn't mention it in the text and it seems silly paying £50 for Junction A when the whole wiring set is £80 but it's in the pics so they better supply it :)

  • Yeah, but I'm climbing unknown gradient mountains and 15 days into the race I might not actually be able to push a standard double or 28/29T - that's what I'm worried about.

    52/36 rings would fit on my cranks but I wonder if it doesn't just make sense to buy a Compact and be done with it?

  • Really? I thought Short Cage was only good for 28/29T?

  • @hippy
    Ribble discount codes on Shimano:
    £10 off £100 - SHIM10
    £25 off £250 - SHIM25

    Can probably break an order up to use codes more than once.

  • Yeah, I got those yesterday but their new site is shitty and kept timing out so I only started parts building now. Cheers. I'll compare them with Merlin and see who's winning.

  • Totally personal. But in my opinion the campag 12-29 is a nicer spread than the Shimano 11-28. I'm not keen on the missing 16T on the Shimano. Its also kinda Nice that my training/climbing Wheels have 2 bigger cogs than my 11-25 crabon Wheels.


  • So far, Ribble is beating Merlin - their FD is cheaper and I can't find a cable set on Merlin.

  • You lost me at 'campag'.

  • Must be a Shimano Version out there.

    I havent noticed Complete cable sets for sale before. So might be pretty rare, or a ribble thing.

  • I can't find any di2 cables on Merlin so that's them out.

  • It'll get pricey buying them separatly.

    I recabled my bike a bit when I moved the Junction A. Luckily I could just mix the cables around and just needed to buy one.

  • The Ultegra 6870 rear derailleur’s maximum tooth capacity is 28 teeth. So in order to get it to shift onto that 32-tooth cog, you need to increase its capacity somehow. There are a number of ways to do this.

    One is to use a longer rear derailleur hanger on the dropout to get the derailleur to drop down far enough to clear the largest cog.

    Another method is to max out the b-screw adjustment (possibly in combination with the longer derailleur hanger as well) to get the derailleur to swing back far enough to clear the largest cog. It may require taking the b-screw out and putting it in from the opposite direction so the b-screw’s head contacts the tab on the derailleur hanger.

    Finally, the most elegant solution is to use a longer jockey wheel cage on the derailleur. You can buy an Ultegra 6800 GS long-cage triple rear derailleur and interchange its jockey wheel cage with the one on your 6870 Di2 rear derailleur. That cage is compatible with 32 teeth on the large cog. You’ll still be left with a perfectly functional cable-actuated Ultegra 6800 11-speed rear derailleur when you’re done, in addition to your long-cage 6870 Di2 rear derailleur. There are also aftermarket solutions to get more gear capacity; check out Ian’s comment below, who had written me months ago about a similar issue.

    I’m using Dura-Ace Di2 with Dura-Ace 50/34 compact chainrings and XTR 11-36 rear cassette with the K-Edge long cage, designed to let you use Di2 on a mountain bike. It has worked flawlessly and is a brilliant solution for heavy and/or loaded and/or weaker riders in the hills.
    — Ian

    Read more at http://velonews.competitor.com/2013/08/b­ikes-and-tech/technical-faq/combining-an­d-caring-for-electronic-and-mechanical-s­hifting-components_299684#Q8Mrefl1o7jKy1­Mf.99

  • "The latest version of Ultegra 6870 Di2 officially increased the cassette capacity to 30 teeth and I have had good luck with cassettes up to 32 teeth on the current generation."


  • YMMV but me Julie's bike has had 50/34 and 11-32 with a short cage from new, it's fine.

  • Actually in shimano doesn't have "large" cage. It's short or medium cage.
    For the "same" I thing it's better the medium cage in order to use bigger cassette.

    On the TransAm I used a 52-36 Doval 16% ovality with 11-32 cassette.

    It's pretty flat extensions, and the hardest summits are McKenzie Pass (km 520) 16 kms at 6,5% and other in Appalaches to get the Blue Highway (something like 4 k at 9%).

    For the Transcontinental I'm thinking to change the rings to 50-34, because the TCR#4 has more climbs and less long distances to rolling (I think only the firsts days to Laussane I can use long gears, and when you ride fresh you can move more cadence! So it shouldn't be a problem ).

    I can get you some Doval chainrings to test if you want.
    Some studies speak of 4-6% power gain. I think that it's true, because probable used another diferent muscles, and reduce toxic generation (formerly called lactate)

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Electronic & Hydraulic Shifting (Di2, Ui2, customisations)

Posted by Avatar for hippy @hippy