After years of watching, waiting and developing in the shadows, industry giant Shimano has pulled the curtain back on it’s first dedicated gravel bike groupset family, GRX. Released in conjunction with some long-awaited updated to its enthusiast-level Tiagra groupset, GRX is designed for the masses, available in both 1x and 2x drivetrains, both 10, and 11-speed configurations and with either mechanical and Di2 shifting.
So without further ado, join us as we take you through ten things to know about the latest adventure riding groupset family to hit the market, Shimano GRX.
1. Three Levels of Performance
Rather than unveil a standalone groupset, with GRX, Shimano has developed a whole new groupset ecosystem with three levels of performance on offer. Sitting atop the hierarchy, RX810 is said to align with Ultegra, whereas RX600 and RX400 are destined for the OEM market and sit alongside 105 and Tiagra.
As buyers progress through the hierarchy, shifting switches from 10, to 11-speed, components reduce in weight and increase in price, while Di2 and increased gearing options are offered, more on that below.
2. 1x Makes It’s Way to the Road
Almost five years since industry rival SRAM debuted 1x shifting for the road, gravel and ‘cross scene, Shimano has finally taken the plunge and offered an option for riders to ditch the front derailleur. It’s worth noting that the Japanese outfit hasn’t gone all-in on 1x, with 2x drivetrains still dominating the GRX product line-up.
Both 1x and 2x systems are said to be offset 2.5mm compared to a standard road chainline for greater tyre clearance and efficiency. As a result of this, GRX double cranks must be used in conjunction with a GRX front derailleur.
3. Wide Range Derailleurs
Working in conjunction with the new groupsets is a new range of rear derailleurs. Each series scores an individual derailleur option depending on whether users opt for mechanical, di2, 10-speed or 11-speed. There’s also dedicated wide-range 1x options which allow riders to use 11-speed 11-40t and 11-42t cassette options. Riders opting for the shorter cage derailleurs can run either 1x or a double crankset up front but are limited to a maximum cassette size of 11-34t.
In addition to increased range, all GRX derailleurs also score Shadow RD+ chain stabilisation tech first unveiled over on the Japanese giant’s mountain bike groupsets. The spring tension is also adjustable, meaning that riders can fine-tune the amount of tension on the chain to their personal preference.
Finally, top-end RX810 users also have the option to opt for Di2 shifting on both their 1x and 2x drivetrains, with each configuration scoring both short and long cage options.
4. Refined Levers
An evolution of the brand’s ergonomic and highly regarded road STI levers, GRX scores a host of updates in the lever department when compared to its road-going siblings. The brake lever pivot point has been raised to increase brake leverage from the hoods; a scalloped finger rest has been added while the lever blades now feature a matte textured finish for improved grip.
The increased pivot point of the brakes gives a noticeably taller aesthetic and is said to provide more control when braking while descending on rough terrain.
5. Chainring Options Aplenty
Using Shimano’s proven Hollowtech construction on top end RX800 cranks and 24mm axles across the board, GRX offers up a range of different chainring options. As previously mentioned, with the chainline pushed out by 2.5mm, the new chainrings work in conjunction with the new front derailleurs to provide increased tyre clearance. RX600 level chainrings are said to tip the scales at around 100g more than their range-topping counterparts as a result of a forged manufacturing process, rather than using the lightweight and more expensive Hollowtech construction.
Chainring options for each series include; * RX800 1X: 40 and 42T. 2X: 48-31T
- RX600 1X: 40T. 2X: 46-30T (10-speed), 46-30T (11-speed)
6. Beefed Up Braking Systems
In line with its road-going siblings, GRX scores two levels of flat-mount hydraulic disc brakes. The callipers are a dual piston design and are said to use the same pads as existing 105, Ultegra and Dura-Ace systems. RX815 Di2 levers are the primary benefactor of the group though, scoring Servo Wave technology from its MTB stablemates. Servo Wave multiplies the pull ratio of the brake lever, bringing the pads in contact with the rotor quicker for increased braking modulation, power and control.
7. Dropper Post Ready
While the GRX primarily features expected and welcome additions to the Shimano product line-up, two unexpected inclusions are sure to please hardcore gravel grinders. This is the ability to run a dropper post off of a dedicated lever when opting for a 1x set-up and the inclusion of an option in-line brake lever. The RX810 LA allows users to operate a mechanical dropper seatpost, provided it attached the cable head at the lever body, and is said to offer a similar throw to that of a mechanical front derailleur shifter. While the in-line brake lever is a designed to mount near the stem and provide riders with an optional third dedicated riding position; drops, hoods or tops.
8. Gravel Ready Wheelset Debuts
As has been the case with the majority of new groupset additions to the Shimano product line-up, the Japanese outfit also debuted an all-new gravel specific wheelset. The hoops are available in either 700c or 650B diameters, are tubeless ready and feature an internal width of 21.6mm.
9. New Tiagra Additions
Unveiled on the same day as GRX, if not slightly overshadowed, was an all-new in group disc brake option for Shimano’s entry-level Tiagra groupset. The new R4720 levers house the hydraulic disc brake controls and are paired with all-new flat-mount callipers. Also unveiled was a new thru-axle hubset along with a sub-compact 48-34T dual crankset, which sits alongside the existing 50-34T and 52-36T cranksets.
10. Pricing and Availability
Shimano GRX is expected to hit the UK in July (mechanical), with the Di2 components expected to be available from September onwards. At the time of publishing, no official pricing has been released.