Shimano completes GRX Di2 with new wireless 1×12 option

Today Shimano, after a years-long roll-out, completed its GRX 8200 group. The Japanese brand adds its first fully wireless gravel drivetrain, a 1-by 12-speed group modelled after the latest version of XTR.

We’ve had some time on both the new wireless XTR group and the newest addition to GRX. Read on for details of the release and our thoughts on Shimano’s first fully wireless gravel group.

GRX follows XTR to the world of wireless shifting

For the gravel gear-heads following Shimano’s trio of new mountain bike groups, this latest GRX Di2 release would have been clearly foreshadowed the moment the brand hinted the new XTR rear derailleurs would communicate with any current Di2 drop bar controls. If you haven’t been following those releases, because they are mountain bike groups and this is a gravel gear story, we’ll give full details on the new GRX group, what’s new, what’s not that new and some more interesting options the new group opens up.

GRX’s major overhaul started with a fully mechanical group offering three options: traditional 2x gearing, wide-range 1x and a compact 1x option. A year later, Shimano released a Di2 version of GRX 820, but only the 2x group. It was pretty clear what part was missing and, with the release of XTR, what the final piece of the GRX line-up would look like.

The Details: Shimano GRX Di2 1×12

Seeing as this is the final piece to complete Shimano’s 820-series GRX, today’s announcement isn’t a complete group. Instead, there are limited new parts to complete the group, plus some options for those that want to upgrade or update their GRX group. The new parts are a wireless rear derailleur, simplified left brake lever, updated cassette and, at the same time, the launch of a new alloy wheel set.

Shimano GRX 1×12 Di2 Derailleur

The centrepiece, in fact the only really essential piece, to the GRX update is the new rear derailleur (RD-RX827). Like Shimano’s new XT rear derailleur, it is fully wireless, it uses the new Shadow ES chain stabiliser in place of a clutch mechanism and it has the impressive Automatic Impact Recovery function. We’ve talked a lot about this in the XTR launch, but this replaces the “crash mode” on other Di2 groups, which required riders to manually reset the rear derailleur, with an automated return that allows you to keep riding as if nothing happened.

Two really important features for gravel are that the battery and the mount. First is removable battery, which Shimano estimates gets around 700-1,000 km for a full charge, is tucked away under a cover plate inside the main derailleur body. It’s easy to remove to charge, but it’s well isolated from the elements which, in gravel racing, can be extreme.

Second is the mount. Shimano uses a traditional derailleur hangar mount, so GRX will work with almost any existing gravel frame (UDH or otherwise).

What doesn’t carry over from the mountain bike groups is the option for a compact cassette and short-cage rear derailleur. XTR and XT both offer a 9-45 cassette and corresponding SGS-version of the wireless rear derailleur. Both of those systems will work with GRX levers, though, so if you really want to you can run a compact/9-45 combo using parts from either group, the finish just won’t match you’re levers.

A simpler GRX shifter

There’s also a new left shifter (BL-RX825-L) to go with the Di2 1×12 version of GRX. Since all the functional elements are in the existing right Dual Control lever, Shimano’s offering a version of the left lever that is hollowed out of all the unnecessary parts. This saves weight (19.5 grams) compared to the Dual Control lever used with 2×12 GRX. This brake-only version is, of course, an entirely optional upgrade if you already have GRX 2×12 Di2.

Shimano RX180 alloy Wheels

Further expanding Shimano’s gravel range, and helping to counteract the price of GRX 1×12 Di2, is a new set of RX180 alloy tubeless wheels. With a 25-mm internal width and hooked sidewalls, the new alloy hoops are designed to work with tires from 32mm to 50mm wide.

Notably, these wheels aren’t just for the 1x groups. A redesigned rear hub allows for easy conversion between Microspline and HG-L freehub bodies. That means they’ll work with 1×12 or 2×12 GRX and a wide range of 10-, 11- and 12-speed cassettes. Shimano’s stating a 2,105-g weight with the HG freehub or 2,113 grams set up with Microspline. At $370 for a wheelset, these should have solid appeal beyond this GRX launch.

Some interesting options

Since the GRX rear derailleur is basically XT 8200, but with GRX finish, and GRX is compatible with all the new wireless mountain bike gear and HG+ 12-speed drivetrains, there are some interesting options here to save weight, or save some cash.

If you value weight over money or the aesthetics of a matching derailleur and shifter, you can save another 60-ish grams by opting for the XTR rear derailleur with its carbon fibre parts instead of the GRX’s alloy cage. Or you can cut just under 100 grams by upgrading to the titanium teeth of an XTR cassette. As mentioned above, you can also run this GR-XTR combo in the compact, 9-45 cassette option, if you want closer spacing and quicker shifting.

Alternatively, you can go the other direction and save some cash with a Deore-level cassette. Basically, anything that works with the combination of 12-speed HG+ / Microspline standards that GRX 1x groups run off of. Heck, if you want to get really out-there, you can run GRX with any of the three mountain bike shifters for a flat-bar gravel set-up.

Ride Impressions: Shimano goes wireless

While we have minimal time on the new GRX 1×12 rear derailleur, we have enjoyed the latest GRX brakes and hood shape that go with the group for over a year now. Those remain unchanged with addition of the new rear derailleur option.

We also have five full months riding the new XTR group on a mountain bike. That group is proving thoroughly impressive, with features that should translate to gravel well. As mentioned, sheltering the battery inside the derailleur body in a well-sealed chamber is an obvious benefit to the world of gravel. It’s also worked well during a wet spring of XTR testing on Vancouver Island.

Automatic Impact Recovery is nice, though probably less likely to be applicable to gravel. The shifting speed of XTR is impressive, though. It cruises across the wide-range 10-51 cassette with precision, whether under load or spinning easy. The trimming function is also important to anyone considering running GRX 1×12 for long gravel races, adventures, bike packing or any other scenario where you’d want to keep riding without the support of a mechanic. The third, function button on the GRX shifter allows you to adjust each gear individually while you’re riding. So, if you do crash hard enough and the derailleur isn’t sitting perfectly on one of the cogs, you can get it back into line while you ride instead of dealing with hours or days of not-quite perfect shifting. This seems particularly relevant this week as Tour Divide riders make their way solo from Banff, Alberta to New Mexico. In fact, Canadian icon Svein Tuft was running a Dura-XTR combo for the ultra-distance race (possibly since the race started before the GRX embargo lifted).

Canadian pricing and weights for Shimano GRX Di2 1×12

Pricing and weights are listed for the new additions to Shimano’s GRX group.

Shimano GRX Di2 component	Price	Weight (g)
Shifter set: BL-RX825-L / BL-RX820-R	$442.99	188
Rear derailleur, RD-RX827 GRX	$768.99	454
Battery (BT-DN320)	$75.99	26.5
Charger (EC-DN100)	$63.99	n/a
RX810 Wheelset	$369.99	2,105 / 2,113
Cassette (CS-M8200-12 – Deore XT)	$260.99	463
Existing GRX parts (2×12)
Disc brake rotor, RT-CL800, 160 mm with lock ring	$88.99	169
Chain, CN-M8100, HG 12-speed with Quick-Link	$71.99	252
Crankset, FC-RX820-1	$362.99	644-656