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 aluminum 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 optimizes shifting. With a total capacity of 37 teeth, you can shift 12-speed cassettes with a largest sprocket of 28 to 32 teeth.
Specifications:
Series: Dura-Ace Di2 R9250Application: Road, Triathlon & Time Trial
Gearing: 12-speed
Mount: standard (Direct Mount compatible)
Capacity: 37 teeth
Compatibility: Shimano Road 12-speed
Compatibility - Chains: HG 12-speed
Technical Information:
Derailleur Pulleys: 11 teethOuter Cage Material: carbon (CFRP)
Inner Cage Material: carbon (CFRP)
Other Materials: aluminum, carbon (CFRP)
Compatibility:
Power cable: EW-SD300 (1 x connection)Shift/brake handle: ST-R9250, ST-R9270, ST-R9160, ST-R9180, ST-R8150, ST-R8170, ST-R8060
Cassette: CS-R9200-12, CS-R8100-12
Chain: CN-M9100, CN-M8100, CN-M7100, CN-M6100
Charging Cable: EW-EC300
Features:
- function button, charging port and wireless system in one compact unit- Di2 wireless chip with low interference probability, high processing speed and low power consumption
- LED status display (battery, pairing, settings mode, Synchro Shift)
- extremely high shifting speed: 58 % faster than RD-R9150
- flat design
- connected to battery via cable
- only one cage length for all gradations
- firmware updates via E-Tube Project
- 4 fluorine-coated joint bushes
- tension and guide roller bearing
- painted cage plates
Technology:
Shadow RDShadow rear derailleurs from Shimano have a very flat profile, allowing for a more aggressive riding style by minimizing 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.
Shimano Synchronized Shift
Shimano's synchronized shifting function is a shifting mode that automatically matches the Di2 rear derailleur and Di2 front derailleur. It is activated either via the E-Tube platform or via the rear derailleurs with a function button. Synchro Shift means that the front derailleur automatically selects a suitable gear depending on the position of the rear derailleur, while Semi-Synchro Shift means that a suitable rear derailleur position is automatically set when you operate the front derailleur. This gives you the advantage that you only have to concentrate on one side of the shifting process and are not thrown off-rhythm by sudden unfavorable changes to the gear ratio.
Models:
Long Cage:Max. Largest Sprocket Teeth: 34 teeth
Min. Largest Sprocket Teeth: 28 teeth
Max. Smallest Sprocket Teeth: 11 teeth
Min. Smallest Sprocket Teeth: 11 teeth
Max. Chainring Difference: 16 teeth
Total Capacity: 37 teeth
Manufacturer Number: I-RDR9250A
Contents:
- 1 x Shimano Dura-Ace Di2 RD-R9250 Rear Derailleur- 1 x Shimano TL-EW300 cable tool
Gram Weight:
- black/long: 215 g (Grams)
