Mate runs R8000 GS rear mech (non Di2) with 11-40 XT cassette. I agree with edscoble though, 46/30 chainset neater solution. Also for the long climbs on TNR a couple years ago v my weedy legs I swapped to a M785 38/24 chainset and M785 front mech (RS685 shifters, 6800 rear mech & 11-36 cassette).
Mate runs R8000 GS rear mech (non Di2) with 11-40 XT cassette. I agree with edscoble though, 46/30 chainset neater solution. Also for the long climbs on TNR a couple years ago v my weedy legs I swapped to a M785 38/24 chainset and M785 front mech (RS685 shifters, 6800 rear mech & 11-36 cassette).