Shimano Dura-Ace Di2 Yumeya carbon fiber cage hack to put it on a mountain bike

Bikerumor reader Ricardo Wang just sent over this little hack.

After digging through his parts bin, he remembered a Yumeya carbon fiber XTR derailleur cage he’d purchased and never used. Turns out it’s a perfect fit for the Dura-Ace Di2 rear derailleur. While he says he doesn’t plan on using it, it’s a fairly cheap experiment compared to the full Ki2 kit from K-Edge, which he compares on his blog. Of course, you’d still need most of a Di2 group and K-Edge’s nifty machined shift pods.

Shimano Dura-Ace Di2 Yumeya carbon fiber cage hack to put it on a mountain bike


  1. what youve got is a long cage road front derailleur, far from a mtb derailleur. it’ll have the necessary capacity, but it will still limit your max cog size. k-edge offsets the upper pulley a lot to help it clear.

  2. I second what you say, Greg

    The excitement of 11-34 ten speed cassettes being available from Shimano (I’d tried the IRD version earlier) led to many destroyed long cage road derailleuers.

    The long cage takes up the chain slack

    The distance between the pivots on the mech body determines tha maximum size cog

    This is still a road mech!

  3. It was for giggles.

    I get it it, it’s a Road mech!

    People need to read the blog, without actually just scanning it. At no point have I ever mentioned that it was a mountain bike mech, I said it could be.. since you can use it upto 32t. never mentioning it for 34t or any teeth for that matter.

    What I said was…
    “What applications is this for you may ask? Well this could be used on a mountain bike or if you decide to run a 13/15 pulley combo there is plenty of room you just need some slight modifications.

    A disclaimer. This kit has not been tried out or fitted on a bike. I have no intentions to try it! but you can see It’ looks pretty darn good! so be my guess if you want to try. I and Flwrider will not be held repsonsible! Happy Hacking!”

    I have not seen anyone do this or even documenting this. Whether it worked or not. The point of this excercise is to inspire people to maybe give it a try.

    At the end of the day it’s a hack, Hacks are never perfect. Frankenstein was never perfect.

    If it was designed for a Mountain bike Shimano would have it as XTR Di2.

    If anything this excise proves that Shimano uses similar designs in their mechs. The M970 SGS has the same fittings as the Durace 79xx series.

    However it “could” be use for a ROAD mech as a cage to house a 13/15t pulley combo.

    Anyhow I have never needed to use anything larger than 32t, my present setup is a 2 x 10 running 42t and 27t with a 11 – 27t casette. however this is for cross country.
    In case you are wondering I am running 10spd XTR M980.

    Gillis, you need to see my parts bin.. Things get forgotten all the time. This Yumeya plate I originally got was to try and fit to my M972 ( However it was for a M970SGS so it would never fit.

    This is my bike stable.
    My Roberts, that’s how I left it, I took it out 15 years later to take pictures of it.. I have not ridden it in 15 years!
    My Viner is my latest project.

  4. ricardo,
    i hear what youre saying. believe me, i’m all for experimentation. theres a reason i knew this situation already.
    this derailleur, to be used for mountain biking, as a substitute to the Ki2 version, was implied by Tyler here, that’s all.

What do you think?