First Look: Shimano GRX Gravel Groupset

First Look: Shimano GRX Gravel Groupset

Written by Contender Bicycles, on March 03, 2021

For better or worse, Shimano is generally the marker of traditional conservatism in the cycling industry. Rather than reaching for any and all budding trends, Shimano studies, prototypes, and tests. That might come off as timid or slow to react, but it is a large reason why they're seen as the gold standard in reliability and quality in just about everything they do. That's where the new Shimano GRX gravel groupset comes into view, as a groupset that signals Shimano's decision that gravel riding is here to stay. Shimano GRX Groupset - Contender Bicycles The Shimano GRX group isn't a fundamental redesign of what we are used to seeing on gravel bikes but a refinement of their road drivetrains to match what works best while riding on mixed terrain with drop bars. Here, you'll find a focus on riding with flared drop bars, plenty of tire clearance, and wide-range gearing. Shimano GRX Groupset - Contender Bicycles - Gearing There are three different groupsets in the GRX line: ten-speed mechanical (RX400), eleven-speed mechanical (RX600 and RX810), and eleven-speed electronic (RX815). All three groups feature the option for 2x subcompact gearing (46-30t for ten-speed, 46-30t or 48-31t for eleven-speed), while eleven-speed models add a 1x option with a 40t or 42t chainring. Ten-speed groups can use up to an 11-36t cassette, while eleven-speed groups can use up to a recommended 11-34t (2x) or 11-42t (1x) cassette, all of which use the standard Shimano HG spline the Japanese brand has used for nearly thirty years. None of this is far off from what is already pieced together by gravel cyclists, but there are a few fundamental changes here. Shimano GRX Groupset - Contender Bicycles - Shifters Perhaps the most obvious difference between GRX and Shimano's road groupsets is at the shifters. Shimano found that most riders tended to use their brakes most frequently with hands on the hoods rather than the drops. This led Shimano to make a few key changes, including anti-slip textured hoods, scalloped brake lever blades that fingers naturally rest on that are finished in matte rather than gloss, and brake lever pivots that are raised by 18 mm. All of this is done in an effort to improve braking leverage from the hoods. As a result, GRX shifters look a little wonky, particularly the GRX Di2 shifters that look a lot like old-school Modolo aero brake levers. These shifters work interchangeably with other Shimano road eleven-speed derailleurs and Shimano road eleven-speed shifters, but if you ride a lot of dirt, these are the way to go for their improved braking and ergonomics. Shimano will also offer 1x-specific left-side levers, ala SRAM 1x mechanical levers. What's unique is a dedicated left-hand lever with an integrated dropper remote, available only with Shimano RX810 shifters and 1x drivetrain. It is definitely a cool option that doesn't require awkward dropper lever placement or kludging a 2x shifter to work properly. Shimano GRX Groupset - Contender Bicycles - Cranks Shimano has hopped on the subcompact gearing bandwagon with GRX, a move many have patiently waited for rather than using the myriad of aftermarket options already available. Ten-speed drivetrains must make do with a 46-30t crank, while eleven-speed drivetrains have the choice of native 1x and 2x gearing. The GRX RX-810-series crank features their Hollowtech construction to cut weight, as well as 48-31t gearing. Paired with the recommended 11-34t cassette gets riders close to the low gearing that SRAM's Eagle drivetrain famously offers. The simpler GRX RX-600 crank still offers 1x and 2x gearing options, though it uses solid forged crank arms that add a bit of weight. All GRX cranks move the chain line out by 2.5 mm to accommodate a front derailleur and wider tires compared to typical Shimano road cranks. It's not a problem we've typically had, but it is nice to see that Shimano thought these things through. Shimano GRX Groupset - Contender Bicycles - Derailleurs Making all of this work together is a pain without a proper rear derailleur, but Shimano has all of their bases covered. There are five derailleurs total, all of which share a lot in common with Shimano's Ultegra RX clutched rear derailleur. Besides the integrated clutch to offer improved chain tension and reduced chain slap, each rear derailleur uses the same cable pull as current Shimano road shifters. Translation? You can now use your current Ultegra shifters with a GRX rear derailleur and run an 11-42t cassette without adding anything to the drivetrain to make it work together. And while not "en vogue" per se, Shimano has also given their front derailleurs some attention, adjusting them slightly to accommodate the 2.5 mm outboard chain line. Shimano GRX Groupset - Contender Bicycles - Brakes Brakes are largely unchanged compared to current Shimano road groupsets, though GRX signals a comeback for inline hydraulic brake levers. Historically, inline brake levers often led to mushy brake feel, though these Shimano GRX hydraulic levers should be just as smooth as a standard brake lever. How does this translate to how the new GRX group feels in the real world? Great question; though we haven't yet gone out on any big rides yet, GRX isn't a ton more than an adoption of what we were already putting on gravel bikes. We know that subcompact gearing and 1x drivetrains are the way to go for an all-road bike, and Shimano offers that here. But in typical Shimano fashion, everything has a polish to its action that can truly only be had when a full Shimano group is used. Even with the new GRX gravel group, Shimano is the marker of traditional conservatism in the cycling industry. Many say they were late to the party, but clearly their arrival solidifies gravel bikes as a legitimate subsection of cycling that deserves the support of one of cycling's largest manufacturers. We're excited to get out and about on this groupset more in the near future, but needless to say that many people will be happy that Shimano took their time to offer up their latest groupset. Have any questions about Shimano GRX, GRX builds, or GRX-equipped gravel bikes in the shop? Give us a call during business hours, or send us an email to


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