The Pinnacle of Shifting and Braking.
Shimano's Di2 drivetrain continues its evolution and with the release of R9100 components, Shimano developed an entirely new hydraulic disc brake system comprising of STI shift/brake levers and new flat mount calipers. Previous versions of the top-tier Di2/Hydro levers and calipers were handled by the ST-R785 set, a model that wasn't confined to a group and most likely a place keeper until the UCI decided where their stance on road bike disc brake use in competition would lie. This marks the first time we see hydraulic disc brakes under the Dura Ace moniker and we couldn't be happier. Shimano's excellent E-Tube project offers customizable shifting set-up so no matter your cycling discipline, you are fully in control in how you are able to program your shifting. Sold as individual right and left levers, the levers include specific BR-R9170 flat mount brake calipers and hydraulic hose kit.
The ergonomics of the new 9170 hydraulic lever is nothing short of phenomenal. It's much slimmer than before and is very similar to the silhouette of the non-hydro Di2 and mechanical versions of 9100. Shimano also worked on making the clicks more positive which provides great feedback when trying to operate the levers in freezing conditions with thick gloves, during a muddy cross race, or over washboard gravel roads. Caring over from previous versions is the ability to integrate satellite buttons for climber and sprinter shifters. The new textured hood provides excellent cushion and grip and simply disappears when we are riding.
We are not surprised that Shimano waited until the Dura Ace version to include the flat mount brake calipers. By doing so, Shimano was able to drop weight while increasing power and offer even more or their highly vaulted modulation. The caliper is very low-profile and the finish matches the rest of the Dura Ace group. One of our favorite things about Shimano brakes is that it uses mineral oil, safer for the environment and won't harm your frames finish. Shimano worked hard to keep operating temperatures low. No one wants to carry around large heavy rotors on the road, so it looked at design and material use on the rotors, pads, and pistons. Finned, resin pads are used which are super quiet and offer the best modulation. The aluminum fins dissipate heat quickly and allow you to run smaller diameter rotors without the fear of overheating or fading on long descents. Ceramic pistons shield the caliper and fluid from the heat generated by the pads. An aluminum core draws the heat away from the face of the stainless steel rotor. Flat mounts are becoming the standard on newer cross, road, and gravel framesets and most of the ones coming through the doors at Competitive Cyclist are sporting them. Flat mount calipers are backwards compatible so if you are looking to put these on an older disc frameset you will be fine with adapters. In the wind tunnel, flat mounts have less of an impact on aero performance versus post mount so if you are fretting aero drag as a deciding factor, worry no more. Rotors are sold separately and the IceTech versions in 140 or 160mm are highly recommended.
The new E-tube Di2 system allows for a completely custom shifting setup. To take advantage of this system you will need to use a BM-DN100 or BT-DN110 battery and the EW-WU101 ANT/BLE wireless connector to connect to your tablet or phone. Each shift lever is programmable to operate either derailleur and you can choose if you want that button to upshift or downshift. Shimano also adds SyncroShift which helps to manage sequential shifting with two options. In fully synchronized mode, the front derailleur will automatically shift up or down based on the position of the rear derailleur and the set ratios you determine in the app. In semi-syncronization mode, you will still shift front and rear derailleurs normally but after a front shift is initiated, the rear derailleur will upshift or downshift depending on the direction of the front shift to keep cadence optimal and allowing you to focus on pedaling and not gear ratios.
Shimano's Di2 shifting is the gold-standard in which all other shifting is compared and we are excited that a hydraulic disc brake option now exists that proudly wears the Dura Ace badge. Mating superior, all-weather braking power and modulation with the industry's best shifting creates the most desirable components for your current drop bar bike or your next dream build.
- Dura Ace level Di2 STI road levers/brake caliper set
- New ergonomics keep the hood size the same as non-hydro shifters
- Refined lever shapes with more positive shift response
- Free-stroke adjustment for lever and pad contact placement
- E-Tube allows for SyncroShift modes and button customization
- Mineral oil is safer and resistant to high temperatures