New Shimano Release 2×12 GRX RX825 Di2 Gravel Groupset

After releasing the 12-speed GRX in September 2023, Shimano added a 12-speed gravel riding electric in late May as they released the 2×12 GRX RX825 Di2 components. While Shimano's 1×12 GRX offers a lot of mountain bike group sets, the 2×12 mechanical iteration shares a lot with their road groups–and the same can be said for the 2×12 GRX Di2.

As such you'll see two control levels optimized for comfort and control, a Shimano Shadow Plus equipped rear derailleur for improved chainring control, and a stone-tuned front derailleur for seamless shifting. The 2×12 system is designed for gem riders who appreciate all the gear range and chain safety that a front derailleur offers, and the new 2×12 GRX Di2 should do just that, with a wireless cockpit and a number of customization options.

A closer look

One of the advantages of Di2 switching is lightning fast switching with almost zero effort. Even better, the shift effort remains the same regardless of load or conditions. Shimano's Hyperglide+ shifting means the 12-speed chainrings and Shimano Ultegra and Dura Ace cassettes have shift ramps for safe and quick shifting up or down the cassette under load. First introduced on the current generation XTR, Hyperglide+ is a big part of what makes Shimano's best shifting 12 speed road bike groupset.

The electronic tricks on Shimano's 2×12 GRX Di2 follow the lead from their 12-speed road sets. As such, the shifters are wireless, using two coin batteries (CR1632) and Bluetooth connectivity to the derailleurs. These are connected via a cable and connected to the battery, for longer battery life and extended performance. Shimano claims that the coin cell batteries can last more than 3 years–which is what we like to hear given the high burn rate of most coin cell batteries on the market.

Given the difficulty of riding on rocks, the shape of the hood brings a raised hood and a textured finish for off-road use, as well as a third button on the hood for customizing the electronic controls. This may be a great Flight Deck toss for some, but the beauty is in how you set up your journey—more on that below.

Shimano also designed the accessory shifters to sit inside the stem clamp, allowing you to ride in a more upright position while still having full control over your movements.

Like the GRX 2×12 machines (see our review here), Shimano has improved the rear derailleur with a sliding clutch and design to keep it healthy and out of harm's way for real. Riders familiar with Shimano's electronic range of DI2 groupsets and E-bike systems will understand that the magic comes with the E-tube app, and the ability to customize your equipment. That's left to the 2×12 GRX Di2, which gives you the power to decide which shift button, and how many gears can be shifted at once. Shimano's new Front Shift Next update means you can set the system to program a button to move the front derailleur to another chainring–regardless of which ring it's on. This is convenient for quick gear shifting when testing the brake. stone racing, or quickly grabbing a bunch of gear for that big attack.

Gear range

With 31/48 and 30/46 tooth crank sets and cassette options of 11-34 or 22-16 (or a tighter width) Shimano's 12-speed GRX range offers a full range of greenstone adventures in turns on the Mt Paris Dam road– or on any gravel race that strikes your fancy. A step closer to change will suit racers, or those with one drop-bar bike to rule them all.

So, is this the new Di2?

Yes Yes. For systems with front derailleurs. But it looks like we'll have to wait and see what Shimano does with a dedicated Di2 mountain bike. This GRX system is an update of the GRX Di2 from 11-speed to 12-speed, taking key technologies from what is already used in Shimano road groupsets. Shimano has 1×12 Di2 groupsets already set–right under your nose on most EMTBs on the market. But these are still a wired system, which makes perfect sense for an EMTB that already has a large power source.

However, for those waiting for a dedicated 12-speed (or 13-speed?) set from Shimano–this isn't really an indication of what's to come. So we are left waiting and wondering.

Shimano 2×12 GRX Di2 will be available as you read this–contact your local Shimano dealer for pricing or more information.