Shimano Dura-Ace Di2 Shadow RD-R9250 Rear Derailleur 12-speed

The Shimano Dura-Ace Di2 Rear Derailleur RD-R9250 – Communication unit with charging port
The RD-R9250 12-speed rear derailleur is the central element of Shimano’s top-of-the-line Dura-Ace Di2 road bike groupset when it comes to semi-wireless as well as fully-wired shifting. It consists mainly of aluminium and carbon, and therefore has a weight savings of almost 50 grams compared to the Ultegra model. The RD-R9250 has even more to offer than a conventional rear derailleur, because in the disc brake version it communicates wirelessly with the shift/brake levers via the built-in wireless chip. In the rim brake version with a cable connection to the STIs, it is responsible for coupling the components. This is done via a function button, which is also used to adjust the rear derailleur. You can also use the button to check the battery level, change the shift mode from manual to Synchro and Semi-Synchro Shift, and establish a Bluetooth connection to a bike computer or smartphone. An LED display helps you to do this.
The rear derailleur is connected to the battery via a cable, from which a cable also runs to the front derailleur and possibly to the STIs. It has a charging port that allows you to easily recharge your circuit using the matching charging cable. In racing and training use, RD-R9250 convinces with an extremely high shifting speed that clearly surpasses that of its predecessor. Its flat Shadow design reduces the risk of snagging and optimises shifting. With a total capacity of 37 teeth, you can shift 12-speed cassettes with a largest sprocket of 28 to 34 teeth.
Information regarding the return of batteries and electrical equipment:Information on the return and disposal of batteries and electrical equipment can be found here.
Specifications:Series:Dura-Ace Di2 R9250Application:Road, Triathlon & Time TrialGearing:12-speedMount:standard (Direct Mount compatible)Capacity:37-toothCompatibility:Shimano Road 12-speedCompatibility – Chains:HG 12-speedTechnical Information:Derailleur Pulleys:11-toothOuter Cage Material:carbon (CFRP)Inner Cage Material:carbon (CFRP)Other Materials:aluminium, carbon (CFRP)Compatibility:Power Cable:EW-SD300-I (1 x connection)Shift/Brake Lever:ST-R9250, ST-R9270, ST-R7170, ST-R9160, ST-R9180, ST-R8150, ST-R8170, ST-R8060Cassette:CS-R9200-12, CS-R8100-12, CS-R7100-12, CS-R7101-12Chain:CN-M9100, CN-M8100, CN-M7100, CN-M6100Charging Cable:EW-EC300Features:function button, charging port and wireless system in one compact unitDi2 wireless chip with low interference probability, high processing speed and low power consumptionLED status display (battery, pairing, settings mode, Synchro Shift)takes over the function of previous wireless units in establishing a wireless connection with compatible cycling computersextremely high shifting speed: 58% faster than RD-R9150flat designconnected to battery via cableonly one cage length for all gradationsfirmware updates via E-Tube Project4 fluorine-coated joint bushestension and guide roller bearingpainted cage platesTechnology:Shadow RD
Shadow rear derailleurs from Shimano have a very flat profile, allowing for a more aggressive riding style by minimising the risk of getting stuck on obstacles. In addition, the single preload ensures that the rear derailleur does not hit the chain stay even on very uneven ground. All of this contributes to a quiet, clean-operating gearshift.

Digital Integrated Intelligence (Di2)
Di2 systems are the electronic shifting systems from Shimano. They are based on the SEIS, the Shimano Electronic Intelligent System, which takes over the index shifting function from the mechanical components, only via power cables or radio signals and not via a Bowden cable. Shifting is done by simply pressing a button. This has the advantage that no great effort is required, your concentration on the ride is not disturbed and operation is easy even with cold hands. In addition, the electronic gear changes are very fast and highly precise. There is also no risk of a defective circuit due to dirty cables or other problems. You can adjust individual settings via the E-Tube Project, such as adjusting the shifting speed, the number of shifting operations per button press or the Synchro or Semi-Synchro shifting function. Shimano offers an app for this purpose. Gear maintenance and firmware updates are also done via E-Tube, with the bike connected to a PC running the appropriate E-Tube software for more extensive workshop work.

D-Fly
Shimano D-Fly is a Near Field Communication (NFC) network that allows Shimano E-Tube electronic components (Di2, STEPS) and smartphones or compatible bike computers to communicate with each other. For example, it is possible to view information about the components on the display or to track power meter data. Shimano provides the E-Tube Ride app just for this purpose. D-Fly is compatible with ANT+, ANT as well as Bluetooth. Network partners include Garmin, Wahoo, Sigma and Cateye for Di2 components and Garmin and