DI2 Ultegra Shifting w/ XT Rear Der

[CQbert81]

Current Setup:
2018 Stigmata Ultegra DI2 (R8050), 2 wheelsets - Mavic Kysrium Pro 11x32 (Road), Shimano XTR 11x34 (Dirt).
I am running 2 wheelsets to be able to hit the road and dirt when I want to with the change of wheels and chain.

I need a lower gear for the dirt and looking to run an 11x40 casette while still running the road 11x32 cassette on the road wheels

Does anybody know if the Shimano E-tube Project has this capability?

Thanks
Chris

[NickJHP]

AFAIK, it will work with the road shifters provided you use an MTB Di2 FD as well. You can't mix an MTB Di2 RD with a road Di2 FD.

But if you have the longer cage R8050 RD, it should work with an 11-40. This YT video shows an unmodified R8000 RD coping with an 11-40 cassette: https://www.youtube.com/watch?v=roUXWvAN-9k.