It comes with multiple configuration options, including monoplate and double-plate transmissions, mechanical or electronic change, 10 and 11 speeds, integration of the telescopic seatpost and wide-range or near-specific gear ratios for any type of gravel and adventure cycling.
After an exhaustive process of research, development and testing that has incorporated the experience of cyclists of all levels on the asphalt and trails, Shimano presents the new GRX series, the first family of components specifically designed for gravel and adventure cycling, designed to roll quickly and safely on loose gravel or dirt surfaces.
GRX offers the series of components RX800, RX600 or RX400, with transmissions 1 × 11, 2 × 11 and 2 × 10, as well as options of mechanical and electronic change Di2, which allows the cyclist to build to his measure his experience on mixed land and go beyond their usual limits in search of a wider range of land.
At the time of creating this series, the Shimano development team went even further with the aim of launching a platform that covers the current and future needs of cyclists. Whether in gravel, modern road adventure cycling, bikepacking or the most demanding cyclocross, SHIMANO GRX provides options ranging from gear ratios adjusted to gravel, custom ergonomics, integration of the telescopic seat post and specific GRX wheels with rim profiles more wide
Going into detail, GRX includes three options of cranksets -1 × 11, 2 × 11 or 2 × 10 speeds-, in addition to derailleurs and rear changes, brake bridge disc with option of brake lever in line, and handles Left and right hydraulic STI, which come with both the Di2 change and the mechanical shift option.
These components employ the leading technologies of SHIMANO transmissions, coming from the road and the mountain, in order to provide the precision in the change and stability that are distinctive of the brand. The result with GRX is a smooth and silent transmission that has been specially adjusted to the characteristics of gravel, both in relation to the terrain, as well as the position of the cyclist and the design of the bicycle.
Looking for maximum simplicity for the user, SHIMANO GRX recommends the cassettes and chains that are already part of its range for MTB (Deore XT, SLX or Deore) or road (Ultegra, 105, Tiagra). In addition to the GRX 800 main series, there are pushbuttons and cranks of the 600 series that combine perfectly with the components of the 800 series and the sets of connecting rod, derailleurs, buttons and brakes for 10 speeds. This means that you can mount any configuration, from a superlight bike to compete to a more economical and powerful bike for leisure trips
Connecting GRX sets:
The GRX cranksets are designed for different terrains and styles; all bring a chain line with + 2,5mm for wider tires and greater distance to the frame. Monoplate cranks offer the simplicity of the unique change in the rear cassette (options include the RX800 / 600 40T and RX800 42T cassettes) and feature Shimano Dynamic Chain Engagement profile teeth on the front plate that provide greater chain retention on rough terrain . Likewise, the RX810 double-plate GRX rod carries a jump of 17 teeth, at 48-31T, which is the broadest ratio developed by the brand so far. Together with the additional options RX600-11 / 10 46-30T, the double-wishbins provide sufficiently wide gear ratios to attack the steepest slopes.
GRX front derailleurs (FD): (FD):
Complementing the connecting rods, the Di2 (FD-RX815) or mechanical derailleurs (FD-RX810 / RX400) have 2.5mm more space for wider tires (up to 42mm), to tackle harder terrain. The GRX derailleurs must be combined with the SHIMANO GRX + 2,5mm cranks. Both series RX800, mechanical and Di2, are designed to work with the jump of 17 teeth of the front plate 48-31T, while the FD-RX400 of 10 speeds is adjusted with the plate of 16 teeth of the crankset RX600 46-30T for 10 speeds. All derailleurs deliver the legendary performance characteristic of SHIMANO. SHIMANO Di2 derailleurs can be adjusted perfectly using the simple integrated controls, while the mechanics provide an extremely light shift feel, thanks to its curved ergonomics, a design that allows more wiring options and a screw for the integrated cable that facilitates an adjustment simple and precise.
Rear shift GRX (RD):
Adopting the technology introduced in 2018 in the rear changes, the GRX Di2 rear derailleur (RD-RX815 / RX817) have been designed to make silent, smooth and reliable changes on difficult terrain thanks to the SHADOW RD + chain stabilization system, which minimizes unnecessary arm movement and provides uninterrupted performance. GRX comes with four options, depending on the cassette and the gear change you prefer. Cyclists using the 11-30 / 34T cassette with Ultegra, 105 or Tiagra, will need the rear derailleur Di2 RD-RX815 or the mechanical RD-RX810, while those who opt for the cassette 11-40 / 42 for Deore XT, SLX or Deore will need to use the Di2 RD-RX817 or the RD-RX812 mechanic, both with a cable pull similar to that of SHIMANO road changes.
GRX STI handles:
The action of change in the GRX is possible thanks to a levers of ergonomics specific for gravel (Di2: ST-RX815 or mechanical: ST-RX810 / RX600 / RX400, ST-RX810-LA) in which it emphasizes a pivot axis of handle located 18mm higher, a curved profile of the handle and a textured and non-slip finish that can be safely operated rolling on rough terrain.
To integrate the use of the telescopic seat post into the gravel, SHIMANO has created the hydraulic brake lever for the ST-RX810-LA disc which, used in conjunction with the 1 × 11 transmission, allows to control the telescopic seatpost without entangling the driving position with one more lever. The integrated cable pull system has a 9mm stroke. that handles the telescopic seatpost with a cable terminal inserted in the handle. The SHIMANO GRX also offers left hydraulic brake levers without change mechanisms or for the telescopic seatpost within the RX800 and RX600 ranges in their 1 × 11 configurations. The left handle ST-RX15 (1 × 11 Di2) has three buttons, two side and one top) to handle auxiliary functions of third-party devices such as lights or cycle computers.
GRX brake systems:
One of the main concerns of the gravel cyclist is having enough braking force that allows him to control the speed in very steep descents or in those that appear suddenly. That is why, at the top of the GRX range, one of the variants of the levers of the RX800 series (ST-RX815) offers the Servo Wave technology coming from the Shimano mountain brakes. It will give us a more powerful braking sensation and more modulation for a more aggressive driving. If you prefer the RX810 option without Servo Wave or the levers of the RX600 and RX400 series, they will still provide sufficient braking capacity at the level of the Ultegra, 105 or Tiagra discs, respectively.
Another option to consider within braking, is the sub-brake hydraulic brake BL-RX812-L / R that connects to the main brake line that goes to both the rear and front brake calipers. This sub handle is designed to be mounted on the handlebar and close to the power, which makes it an option when you have your hands on the top of the handlebar.
The brake calipers of the GRX BR-RX810 / 400 range have the same design as the Shimano flatmount brake calipers, which inherit high performance and performance, such as One-Way Bleed in one-way ICE TECHNOLOGIES heat in the pads and discs to offer an efficient cooling that allows a stable performance and for longer.
Wheels Specific for Gravel:
To perfect the experience, Shimano welcomes the innovative spirit of gravel with two sets of 12mm through axle wheels inspired by the gravel / adventure field (WH-RX570-TL-F12 / R12). These tubeless-ready wheels of 700c or 650c (no boost) mean an excellent balance between weight, rigidity and durability for gravel. The throat width is 21.6mm., Similar to the MTB, and one has vertical lag in the 22mm rim.