Over the past few years, Shimano has steadily increased its offerings for gravel-minded riders. First came hydraulic road disc brakes. Then last year there was the Ultegra RX rear derailleur with a clutch to prevent dropped chains. Now, convinced that it’s not just a passing fad, Shimano is going all in on gravel riding with its first ever dedicated gravel group, GRX.
- GRX comes in three levels: RX800, RX600, and the budget-minded RX400.
- RX810 cranks allow a 17 tooth jump between chainrings, from 31 to 48.
- Available in both mechanical and Di2 electronic versions.
- There’s an option for the left shift lever on the 1x version to control a dropper post.
- The brake levers are curved and have a higher axis for more control—there’s also an option for additional brake levers on the bar flats.
GRX will come in three different levels: top tier RX800, RX600, and the budget-minded RX400. The top two tiers will have options for both 1×11 and 2×11 drivetrains as well as mechanical and Di2 electronic shifting for both. RX400 will be 2×10 mechanical only. The components from the top two tiers will also be interchangeable with one another.
GRX may seem like Shimano’s traditional road groups—and in many ways it is including its appearance and how its shifters operate—but there are many tweaks and upgrades that make it most at home off road.
Expanded gearing is one of the most significant features of the GRX series. The top level RX810 series cranks have both a 1x and a 2x option, with the 2x accommodating a 17 tooth jump (48-31) between chainrings for tackling climbs without giving up the ability to spin on descents. Like Shimano’s road cranks, the RX600 cranks will only have a 16 tooth difference up front for 46-30 gearing. The 1x cranks will come in 40 and 42 tooth versions.
The RX800 derailleurs help expand the gearing even further. The short cage version allows for an up to 11-34 cassette while the long cage version expands gearing to a whopping 42 tooth low gear in the rear. You could run the 48-31 crank up front with the 11-42 cassette for a 31-42 granny gear that’s still useful on descents and hard efforts thanks to the 48-11. Both versions of this derailleur will be available in mechanical and Di2.
All GRX rear derailleurs benefit from Shimano’s SHADOW RD+ technology that allows riders to adjust chain stabilization to match their terrain. Turn it on for high quality shifting off road, or flip it off to save watts while on road. Up front, to accommodate the wider tires necessitated by gravel, the chainline in the GRX group has been pushed out 2.5mm over current Shimano road groups. Just note this means that the GRX crank and front derailleur have to be paired together.
Controlling these derailleurs are the GRX dual control levers which have a few tweaks to overcome the demands of gravel. To increase brake control from the hoods, the brake lever axis has been raised by 18mm, resulting in more leverage. And the brake lever itself is slightly curved for easier brake access. Topping the shifters off is an anti-slip texture that keeps hands in place on rough terrain.
When things get too rough for the hoods, there is an option for additional hydraulic brake levers on the tops—either the left brake, right, or both—providing riders with more positions that are useful across a wider range of conditions.
There is no dedicated Di2 left lever for 1x GRX. Instead, there is either no shifting mechanism for a clean look, or, with the ST-RX810-LA/ST-RX600-LA shifter, the option to control a dropper post with the shifter. The jury’s still out on dropper posts for gravel, but that’s a pretty cool bit of integration. There’s also a bit of play in the left 1x lever so that, in the event of a crash, there’s less of a chance of the lever snapping.
RX810 1×11 mechanical will cost $1,350, with 2×11 coming in about $100 more. Di2 1×11 will be $2,167 while 2×11 will be $2,355. GRX will start rolling out this summer with mechanical 1×11 and 2×11 groups available in July and Di2 versions in August.