The most premium combination is the electronic shifting, hydraulic disc brake version, which has the model number ST-R9170. Combining Di2 shifting with road hydraulic disc, it features effortless shifting and braking. Also, it is the only version not to use any steel inner cable for shifting or braking. Replacing the shifter inner cable is the Di2 electrical wire, while replacing the brake inner cable is the hydraulic brake hose.
These shifters will be replacing the non series ST-R785 that came with the Canyon Endurace road bike. The ST-R785 is the first generation of Di2 shifting/hydraulic braking road shifter, while this Dura-Ace ST-R9170 is the second generation. My plan all along was to upgrade the groupset to a full Dura-Ace groupset, from the stock Ultegra Di2 6870 groupset that came with the bike.
Handsome looking Dura-Ace ST-R9170 road shifters, with a very high quality finishing on the levers.
Another view of the new shifters. The lever shape has been subtly refined from previous generations.
Overall shifter shape is very similar to other shifters in the same Dura-Ace R9100 series, which is done by totally redesigning the shifter.
Another overall view of the ST-R9170
Due to the resin Bracket construction, the shifter weighs only 160 grams per side, giving a total weight of 320 grams per pair. This is very lightweight!
The Di2 shifter buttons have been increased in size compared to older Di2 shifters. The clicking feeling has also been enhanced for a better tactile feel.
Electronic button unit looks to be quite well integrated into the lever.
This textured area at the top of the hood hides a button underneath! This button can be programmed to perform shifting functions or control other devices such as the Garmin computer.
Hydraulic hose attaches to the rear of the shifter. Titanium clamp band for weight savings.
From the outside, the shifter looks very ordinary, as the rubber hood hides all the interesting bits underneath. However, once the rubber hood is removed, it looks much more interesting!
...while the top button is linked to the shifter buttons below by another wire running through the area shown above.
Bleeding this hydraulic shifter requires an adapter (included) to enable the standard bleeding cup to reach the bleeding port on the shifter. This is because the bleeding port on the shifter is located on top, in a recessed area.
Slot on side of Bracket to guide the cam of the hydraulic piston, for a Servo-wave effect.
One thing you notice is how many ribs are used to strengthen the Bracket and yet keep it lightweight! This is only feasible as a molded resin bracket (nylon + carbon fibre) is used. These ribs also make removing and replacing the rubber hood very difficult.
Located at the bottom of the shifter are the free stroke adjustment bolt (on right) and the lever reach adjustment bolt (on left).
Hydraulic piston slides along the internal bore of the Bracket when the brake lever is activated.
A quick comparison of the new Dura-Ace ST-R9170 with the older ST-R785. The lever shape is noticeably different, with the Dura-Ace lever having the same curved shape as the mechanical road shifters.
The new Dura-Ace shifter is also lower in height, which makes the new shifter look much smaller in size. This is possible only due to a new hydraulic brake design.
In a separate post, the ST-R9170 and the ST-R785 will be compared in greater detail. From what I can see, the main differences by making this upgrade is a slimmer looking shifter and also lighter weight. Ergonomics will be similar to other road shifters with Di2 or mechanical shifting, while the tactile feeling of the Di2 buttons will be improved.