As pro cyclists resist the road disc brake onslaught, they don't need to compromise. Shimano's R9150 Di2 system is designed for standard road brake calipers. Much has been written about the excellence of Di2, and certainly there are those who opt fo the competition, but nothing shifts like Di2 electronic with the speed, precision, and reliability Shimano is known for, and exemplified at the highest level of the sport by Dura-Ace. The now legendary Di2 electronic shifting version has been advanced, with many refinements and new customizable configuration. The ST9150 Di2 STI Levers for cable-actuated SLR-EV optimized road brakes calipers have a beautiful feel in hand, and improved overall performance. In the process of developing the Dura-Ace R9100 series, new ergonomics and efficiencies were built into the shifting systems for both mechanical and electronic versions, with options added via the E-Tube project for customizing the shifting set-up of the R9150 Di2 models. Given the frame by frame requirements, and personal set-up preferences the buyer still needs to select the Di2 battery build the E-Tube Di2 wire connection kits required.

The new Di2 system offers substantial opportunities for direct customization via e-Tube. You can set your carbon shift levers up for Shimano's SyncroShift with two primary options. In fully synchronized shifting, the front derailleur automatically shifts off the placement and shifting of the rear derailleur in combination based on your choices. In semi-syncronization mode, the rider shifts both front and rear normally, but front shifts are augmented by an automated rear shift to moderate the large jumps and pedal lag that can cause. In normal shifting mode you can still program the shift buttons to your preference for which each shift action each lever actuates, or even control compatible computer head unit mode or screen buttons. The E-Tube system allows to do all this from their app on mobile devices or directly through a PC interface. With E-Tube, your system must all be set-up and physically connected, and for the new system you will need to be using a BM-DN100 (external battery mount) or BT-DN110 (built-in battery) and EW-WU101 ANT/BLE wireless connector.

From a physical perspective, the new 9150 hydraulic lever has noticeable changes from the 9050 version. Slimmer, with much better ergonomics than ever before, as well as lighter weight, these levers shift a more refined electronic drivetrain with a more positive button response. You still have the capability for integrating with for satellite (sprinter, climber) buttons as well (one port per shifter). The new textured hood design provides excellent grip, some mild cushion, and covers the lightweight new plastic composite body housing. The strength and reliability of the housing is what allowed Shimano to engineer the shift action and ergonomics so well, and keep the weight at 115 grams per lever.

The linear action and feel of the brake lever has been optimized for use with Shimano's SLR-EV dual-pivot brake calipers. Ergonomics, the stiffness of the lever, and adjustability have all been refined based on pro rider feedback. Especially noticeable with Dura-Ace BR-R9100 brake calipers, the combination requires less lever pressure for max power, and the lighter pressure feeds back better in tactile response for better feel and control, with less fatigue. While to some riders these may feel like minimal changes, keep in mind that Dura-Ace brakes are simply the best made, at any cost. Power, modulation, feel and control are all industry leading. The mounting bolts and calipers are stiff and inherently reliable. Shimano has also improved the aerodynamics with the R9100 calipers. Sensitive riders will recognize and hail the changes, but all cyclists will benefit, whether they know it or not.

There have been countless reviews and comments about the excellence of Dura-Ace Di2. While other electronic shifting systems have their wondrous features and excellent performance, Di2 is the benchmark that every other shifting system is compared to. Shimano has never rested on their laurels. Witness the E-Tube project, refined lever design, the addition of hydraulic disc brake options, and the most reliable, amazing shifting performance found on a bike. Dura-Ace ST-9150 Di2 STI Levers represent the pinnacle of the industry. While still a wired system (for several key reasons), Di2 R9150 offers the most impressive combination of shifting performance and mechanical braking cycling has ever seen, with zero compromises. Return to Top