Shadow Rear Derailleur (12 speed)
This DURA-ACE Rear Derailleur was announced by Shimano in September 2021. It is part of the 12 speed system, semi-wireless and uses a new battery, the BT-DN300.
This derailleur features a charge port, LED, button and an EW-SD300 type port used to connect the derailleur to the battery. Both the rear derailleur and the front derailleur connect to the battery using a wire. The shift levers send their shift commands to the rear derailleur wirelessly.
The low sprocket maximum is 34T and I expect a lot of bikes to be built up with 11-34T cassettes.
These 12-speed derailleurs use the same charger as the new Di2 power meters, and perhaps even better: the port cover can be replaced when broken.
Crash Mode Reset
Since the main junction functionality has moved to the rear derailleur, Shimano also changed the method of getting out of crash mode. Pressing the button on the rear derailleur would be hard during a race, so you can now shift out of crash mode.
To get out of crash mode on 12-speed road bikes, shift up and down the entire cassette. This video by Rides of Japan explains it well:
Details & Specifications
|Shimano model number:||RD-R9250|
|E-Tube Port type:||SD300|
|Component series:||DURA-ACE R9200 (Road)|
|Downloads:||RD-R9250 / RD-R8150 User Manual|