Next component to be introduced for the new 12 speed road system is the rear derailleur! The new Dura-Ace R9250 rear derailleur has a lot of stuff packed into it, I will get into the details in just a while.
This is the next generation electronic rear derailleur, upgraded from the previous 11 speed R9150. This post will focus on the new 12 speed rear derailleur and what it can do. All these components will go onto the Focus Paralane road bike.
New Dura-Ace RD-R9250 Di2 rear derailleur for 12 speed road drivetrain!
Glossy black surface finishing, in line with the appearance of this groupset. Even the hardware such as bolts and screws are black in colour.
Limit screws and B-tension adjust bolt are still located in the familiar locations, while the motor has been tucked in further inwards.
Even the ends of the link pivots has a black sticker to cover it up for better appearance, as this is
Cage stopper is molded right into the outer plate, instead of a screw-on stopper.
Carbon fibre outer plate for reduced weight. Cage looks rather long, but this is to make it compatible to larger 34T cassettes.
One issue I noticed with the rear derailleur is the amount of grease on it. Many surfaces on the rear derailleur is covered in grease, making for an unpleasant experience when I am handling the rear derailleur and taking pictures of it. I had to clean it up by wiping all surfaces with solvent.
Greasy cage area
Plate member is greasy as well, making the glossy surface even shinier.
Worst area is the matte plastic cover on the motor. Looks terrible for a high end component!
Looks better after cleaning up. Di2 port is still above the motor. and the linkage system looks the same.
There is now an LED on the top side and a button on the under side of the motor unit. This is because this rear derailleur now has wireless capability to communicate with the 12 speed Di2 road shifters.
The saver spring unit, designed to disengage and protect the motor if there is an impact on the rear derailleur.
Carbon fibre inner cage plate as well. Length will be measured in another comparison post.
Small bits and parts that come with the rear derailleur. It is stored in a small paper bag, don't throw it away! The paper alignment guide will be used to set the correct pulley distance from the sprocket.
New Di2 wire tool, smaller to match the new narrower SD300 Di2 wires.
Cable clip on the left to guide the Di2 wire, rubber boot on the right to provide more protection at the connecting port area.
I wanted to connect all the components to test it, but found that I had to charge the Di2 battery first, which is completely flat. For this new system, the charging port is located on the rear derailleur, and it will charge the Di2 battery via a Di2 wire between the rear derailleur and the battery.
Charging cable connected to the rear derailleur, and the blue light indicates that charging is in progress.
On this new 12 speed Di2 rear derailleur, the capability of the previous Junction A and also Wireless Unit has basically been built into it. This makes it very expensive, while also adding some weight to it.
Dura-Ace 12 speed Di2 Rear Derailleur RD-R9250 weighs 216 grams.
The new rear derailleur is about 20 grams heavier than the previous generation 11 speed rear derailleur, mainly due to the longer cage and also more electronic stuff built into it. On the other hand, the weight of the Junction A and Wireless Unit are completely eliminated, which means no weight increase overall.