Shimano Dura-Ace Di2 RD-R9150 Rear Derailleur

Shimano Dura-Ace Di2 RD-R9150 Rear Derailleur Info

The Shimano Dura-Ace Di2 RD-R9150 Rear Derailleur is a wholesale re-design of the fabled rear mech. The biggest practical improvement is that cage and pulley wheels have been moved to accommodate cassettes with a 30-tooth cog. But that’s really the icing on the cake. The rest of the derailleur is much improved as well.

The first thing Shimano did was change the pivot point. Rather than being on the derailleur hanger, it’s below and behind it. This helps get to that 30t cog, but it also places the derailleur below the right stays, both less visible to the wind and to right-side crashes. This innovation first came on mtb derailleurs. The plus for road riding is obvious. It also means that a direct-mount derailleur hanger can be designed on to some bikes.

The change in the pivot point came with a longer cage. thanks to the positioning of the cage pivot, the upper jockey wheel maintains a near constant distance from the cogs, which improves shift speed. The jockey wheels themselves have been hollowed out for both less rotating weight and better muck clearance.

And despite what seems to be weight-adding changes, the derailleur actually drops 13g from 217g to 204g.

The Shimano Dura-Ace Di2 RD-9150 Rear derailleur is designed to work with the Dura-Ace 9150 group. It plugs in to Shimano’s E-Tube wires, which means it can work with 9050 Dura-Ace and 6870 Ultegra Di2 shifters. Likewise, it is compatible with all 9050 and 6870 components. The wires must be purchased separately.