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Shimano GRX is a component series designed for gravel and adventure riders, bikepackers and cyclocross racers, providing a wide spread of possible builds including 10-speed, 11-speed and 12-speed setups, 1x and 2x drivetrains, mechanical and electronic shifting, wide-range or close-range gears, and dropper post integration.
In 2019, Shimano announced GRX, the "world's first dedicated gravel component group" which combines key technologies and components from road and mountain bike groupsets with some added brand new parts that should be ideal for your gravel bike.
Below we've tried to compile everything you need to know about the groupset giant's gravel-specific drivetrains. If you're looking for advice on Shimano's road bike components then fear not, just head over to our complete guide to Shimano road bike groupsets instead!
Firstly, GRX is divided into three different levels:
That's all simple enough, but things are complicated by the fact that you can't get every component at every level. You can't have a complete RX600 groupset because there's no such thing as an RX600 rear derailleur. For instance, if you want an 11-speed mechanical rear derailleur you need to go for the RX800 level. In other words, you sometimes have to mix and match.
Things are further complicated by the fact that, at the time of writing, you can only get the new 12-speed GRX with mechanical shifting. We assume a Di2 version will follow, but for now GRX Di2 is 11-speed only.
With all that said, if GRX is for you it's easiest to decide first whether you want 12-speed mechanical, 11-speed Di2, 11-speed mechanical or 10-speed mechanical. This is the way that Shimano structures everything on its website, and we've followed this in our guide to each groupset and their variants below.
Not surprisingly given GRX's intended use, you get hydraulic disc brakes across the board. Cassette and chain options come from current road (Ultegra, 105, Tiagra) and mountain bike (XT, SLX, Deore) groupsets.
12-speed GRX is the newest update to Shimano's gravel shifting range, providing more gearing options but sticking to mechanical shifting. It's available in both 1x and 2x setups and there are options under the top-end 800 series (called RX820) and the more affordable 600 variant (called RX610).
Shimano have named the new RX820 groupsets 'Unbeatable', 'Unstoppable' and 'Undroppable' - in reality the first two are both the same new 800-series, 1x12 version of the groupset with different cassette and derailleur options, while the latter is the single 2x12 version of RX820.
The 600-series RX610 components haven't been given a fancy name, but at this tier you essentially have new RX610 cranksets and shifters to make your groupset more affordable.
12-speed GRX is the newest update to Shimano's gravel shifting range, providing more gearing options but sticking to mechanical shifting.
It's available in both 1x and 2x setups and there are RX800 configurations and a more affordable RX600 variant.
The GRX 600 series chainset is available 2x with 46/30-tooth chainrings, and 1x with a 40-tooth chainring, priced at £150.
The 2x setups are compatible with an 11-34T or 11-36T cassette which retails for £85 and the 1x setups can be combined with a 10-45T or 10-51T cassette which are £160.
The key difference between the GRX 800 chainsets and the GRX 600 chainsets is that GRX 800 uses Shimano's Hollowtech II hollow crank arm technology to reduce weight.
For the 1x setups you have the option of the RX822 medium or long cage rear derailleur, equipped with the integrated Shadow RD+ chain stabiliser, which are priced at £119.99 each.
12-speed GRX comes with revamped shifters and brake levers which are optimised for flared drop bars.
Shimano offers dedicated GRX STI (combined shift and brake) levers and you can buy them separately as well as in sets.
The 820-series shifter and disc brake set will cost you between £330 and £350, while the 610-series shifter and disc brake set costs between £260 and £280.
The complete groupset prices are:
Shimano's GRX 11-speed is currently the only Di2 shifting gravel groupset offered by Shimano, although it is also available with mechanical shifting.
11-speed GRX has 1x and 2x setups in both the RX810 series and RX600 series.
For 2x 11-speed mechnical GRX, there are also two models available - 48-31T (RX810) for £219.99, or 46-30T (RX600) for £134.99. For both 1x and 2x setups, it is worth considering that the 810-series will give the highest gear ratios.
Di2 11-speed GRX has 1x and 2x setups but belongs to the 810-series only meaning you have the option of a 40T or 42T crankset for 1x, and a 48-31T crankset for 2x.
For 11-speed GRX there's one derailleur with a long cage, belonging to the RX810 groupset which offers a range of 11-42T for 1x setups and a derailleur from 2x groupsets takes a maximum 11-34t cassette.
Mechanical and electronic GRX rear derailleurs are available and all of them use Shimano's Shadow RD+technology.
For 2x setups you can have an 11-speed GRX groupset with either a mechanical or electronic front derailleur.
Compared to regular road front derailleurs, the GRX front derailleurs have an additional 2.5mm outboard clearance to provide space for wider tyres, up to 42mm and for this reason the front mech must be used with the matching GRX chainset.
The 11-speed levers also offer Shimano's dedicated GRX STI technology (combined shift and brake).
The 800-series lever is available for Di2 and mechanical groupsets retailing at £244.99 and £239.99 respectively and Shimano also offers a mechanical shift RX810 left lever that, when used with a 1x11 drivetrain, can control a dropper seatpost, costing £224.99.
There is also a 600-series lever which retails at £189.99.
Shimano GRX also includes 1x11-specific BL-RX810 and BL-RX600-series left side hydraulic disc brake levers with no dropper or shift internals.
You can also buy STI levers and brake calipers in sets with one option for Di2 groupsets and two options for mechanical.
The complete groupset prices are:
Shimano GRX still offers 10-speed mechanical groupset which is only available as a 2x setup, using components primarily from the cheapest GRX subgroup - RX400.
There is no GRX 400 series chainset. Instead, there's a RX600 10-speed chainset with 46/30-tooth chainrings which retails at £109.99.
As with the 12-speed and 11-speed groupsets, 10-speed levers use Shimano's dedicated GRX STI technology (combined shift and brake) and are available to buy on their own or as a set with brake calipers.
Complete groupsets are now more difficult to find but are priced at around £600.
For more details on Shimano groupsets, check out Shimano's website.
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Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.