Shimano 1×12 GRX Di2 gravel drivetrain is completely wireless

The 1x12 Shimano GRX Di2 drivetrain brings truly wireless, electronic shifting to gravel bikes and drop bar mountain bikes.
By Jeff Barber
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Provided photos.

The wireless, electronic Shimano GRX Di2 gravel group is here, and a lot of the tech will be familiar to those following along with the brand’s recent MTB releases. The 1×12 gravel group (or drop-bar MTB group, if you like) launches with an all-new wireless derailleur and a dedicated hydraulic disc brake lever.

Shimano GRX Di2 derailleur

The Shimano GRX Di2 derailleur shares a lot in common with the mountain bike specific XT Di2 derailleur because, well, they are essentially the same. Both weigh around 450g, give or take, and are compatible with the same range of chains and cassettes. The GRX Di2 derailleur attaches to a derailleur hanger and the onboard battery sits inside a sealed compartment within the body.

GRX Di2 derailleur specs

  • Shimano Shadow ES Technology
  • Solid pulley construction
  • Removable and rechargeable onboard battery with 700km to 1,000km range depending on riding conditions (435 to 621 miles)
  • Long Cage RD-RX827 SGS for use with Shimano 10-51T 12-speed cassette
  • $565 MSRP
A close-up view of a cyclist's legs while riding a gravel bike on a dirt path. The cyclist is wearing white cycling shoes and green socks, with the bike's gears and rear wheel visible in the foreground. The background features a mountainous landscape under a clear sky.

With the 10-51T cassette spec, Shimano is betting that riders will prefer a wider, rather than tighter, gear range. SRAM made waves earlier this month with the release of a 13-speed cassette featuring smaller steps in between gears, though the range is limited to 10-46T. In order to address the large cassette, the Shimano GRX derailleur comes with a long cage. Shimano is speccing the group with either a 40T or 42T chainring.

Officially, the newest GRX Di2 group is 1x-only. Shimano is calling it 1×12-speed GRX Di2 to distinguish the drivetrain from the 2×12 wired, electronic Di2 gravel group launched last year.

Three cyclists in a desert landscape, with mountains in the background. One cyclist, wearing a yellow jersey, is adjusting their bike. The other two cyclists are smiling and looking toward the camera, wearing colorful cycling gear and sunglasses. The sun is shining brightly behind them, creating a warm and vibrant atmosphere.

A new shifter-less GRX Di2 brake lever

Technically, this isn’t Shimano’s first wireless gravel group. That would be the aforementioned 2×12 GRX Di2 group, and that group introduced the RX825 (wireless) shifter, which the new 1×12 GRX Di2 system also uses. The shifter/lever combo places two buttons on the shift paddle with a third, customizable button inside the hood.

Since the new wireless Shimano GRX group is 1x-only, Shimano is offering a new brake lever that matches the existing RX825 shifter, but without shifter controls, so that riders can save a bit of weight (and money). Unfortunately, there doesn’t appear to be an integrated lever option for riders who are running a dropper post on their drop-bar bike. For now, riders will need to choose a mechanical shift lever which will have a slightly different feel. We can only hope that it would be possible to pair the third button, located on the inside of the hood, with a wireless Fox Transfer dropper post.

BL-RX825-L lever specs

  • 1×12-speed brake lever option
  • Flared drop bar optimization
  • Anti-slip coating on brake lever surface
  • 19.5g lighter than BL-RX825
  • $345 MSRP

The Shimano 1×12 GRX Di2 group is priced at $2,282, which includes the entire drivetrain (cranks, derailleur, shifters, cassette, and chain) plus hydraulic disc brakes and rotors.

In parallel with the 1×12 GRX Di2 drivetrain launch, Shimano is also adding the RX180 gravel wheelset featuring 25mm-wide aluminum alloy rims, priced at $280 for a pair.

Shimano RX180 gravel wheel specs

  • Replaceable freehub body – switch between MICRO SPLINE and HG L options
  • 25mm internal rim width
  • Hooked tubeless rims
  • Weight: 2105 grams with HG L freehub, 2113 grams with
  • MICRO SPLINE freehub
  • $280 MSRP (pair)
 
Close-up view of a bicycle's rear derailleur and cassette, showcasing the Shimano GRX components and chain in a softly lit environment.
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