Shimano GRX Di2 ST-RX815 shift/brake lever

The electronic/hydraulic Shimano GRX Di2 ST-RX815 dual control lever provides Gravel inspired ergonomics. Particularly striking is the shape of the handle whose hood head is raised to prevent misalignment while the recessed finger notch prevents the hand from slipping upwards. Like the handle, also the lever features an anti-slip coating for greater mixed-terrain control.

In terms of shifting performance the 2x11-speed GRX Di2 STI lever can take full advantage of the well-known digital precision of the Shimano Di2 electronic shift systems and theSynchronized Shiftingtechnology. In contrast the braking performance is optimized by the brake lever's rotary axle which is positioned 18 mm higher than usual and Shimano'sSERVOWAVEtechnology improving the lever's modulation ability.

In addition, the programmable Di2 shift/brake lever features three switches (two on the side and one on the hood's top) that can be used to operate third-party devices such as compatible lights or bike computers. In order to meet the individual needs of the driver, the hydraulic brake lever offers reach and free stroke adjustment as well.

Number of E-Tube ports:2

Synchronized Shifting

Shimano's Synchronized Shift technology is a new feature introduced to their electronic road groupsets, designed to simplify gear choice and reduce decision making in racing situations. When riding at maximum capacity, decision making can be impaired. The less stresses on a rider and the less decisions a rider has to make, the less mistakes they will make. Therefore Shimano Synchronized Shift is designed to choose the next biggest or lowest gear ratio irrespective of whether a gear change needs to be made by the front or rear derailleur.

Shimano's Synchronized Shift technology adds two shifting modes to the standard manual one, in which front and rear derailleur were controlled independently from each other:

Full Synchronized Shift mode:
The front derailleur reacts based on the rear derailleur’s shift action. This essentially means that, when activated, there is no need for two separate shifters to control front and rear derailleurs, the two buttons on one shifter will control both derailleurs.

Semi Synchronized Shift mode:
The rear derailleur reacts based on the front derailleur’s shift action, shifting to the next most appropriate rear gear when the rider makes a front shift.

SERVOWAVE

Because the brake lever absorbs a lot of braking distance right at the start of its movement, the brake pads have disc contact more quickly and it remains more lever travel to adjust braking force. That is why SERVO WAVE brake systems are characterized by faster response, higher performance and shorter idle travel.