Gravel cyclists live to be in the moment. It is why they roll out of their driveway at dawn, venture down lonely, unknown dirt roads, and take on routes and races with unpredictable outcomes. It is also why they demand the best from their gear, expecting precise, reliable, distraction-free performance in all conditions.
Shimano understands and embraces these lofty expectations, knowing that even the smallest hiccup can mean the difference between fun and frustration, failure and success. It is this pursuit that defines the latest addition to Shimano's growing family of GRX gravel-specific components.
Meet the 12-speed Shimano GRX Di2 RX825 series, which includes dual control levers refined for comfort and control, a Shimano Shadow RD+ equipped rear derailleur for better chain management, and a gravel-optimized front derailleur for precise shifting.
Electrified 2x12 Gravel Gearing Options:
This suite of components brings an electronic option to the 2x12 GRX RX820 items launched last year. Like with the RX820 mechanical components, riders can tailor their gearing with the RX820 crank and its 48/31-tooth chainrings or the RX610 crank with 46/30-tooth chainrings. At the back of the bike, both the HG710 11-36-tooth cassette and the full complement of Shimano 12-speed 11-34-tooth cassettes are compatible.
All four of the gearing options listed above now benefit from Shimano's WorldTour-proven Di2 electronic shifting platform. RX825 delivers a wide gear range with tight gear steps so you can spin a comfortable cadence whether hammering at the front of a racing pack, spinning solo down a quiet country lane, enjoying endless dirt road rollers, or tackling a precipitously steep backcountry climb.
Like its 12-speed road siblings, Shimano's new GRX Di2 is wired where it makes sense, featuring a central, multi-port battery that supplies stable, long-lasting power to both front and rear derailleurs. Smaller diameter wires connect directly from the battery to each derailleur, eliminating the need for junctions and streamlining the build process. The central internal battery also simplifies charging and remains secure over the roughest roads, trails, or whatever less traveled path you choose.
The RX825 rear derailleur features Shimano's pioneering SHADOW RD+ technology. With its convenient on/off switch, SHADOW RD+ makes removing your rear wheel easy when turned off. When on, the drivetrain is under additional tension that makes for a quieter ride and more precise shifting.
Like the very first GRX groups, the RX820 and RX610 systems employ a wider, +2.5mm chainline for improved tyre clearance, allowing you to set up your bike exactly how you want without compromise.
Wireless Gravel-Specific Cockpit:
At the front of the bike, Shimano's 12-speed GRX Di2 features a wireless gravel-specific cockpit where raised hoods with ribbed surface texture and anti-slip brake levers provide ultimate hand security no matter how spicy your ride gets. That secure hand position is further enhanced, as it was with the original GRX RX815 Di2 shifters, with the location of the third Di2 button on the inside of the hood. Whether used as another shift location or for scrolling the screen on your GPS device so you do not miss the next turn in your adventure, this third button is another way to fully experience Shimano's electronic Di2 system.
The new Di2 system also allows for accessory shift buttons, another key advantage of electronic shifting. Plugging in one of Shimano's satellite switches, whether on the tops, drops, or on aero bars, riders can more consistently maintain their effort without the need to move their hands. Like the third button on the GRX Di2 dual-control levers, these satellite switches can be assigned various functions including shifting of either derailleur, to control compatible lights and GPS devices, or as a lap button during workouts.
The new dual control levers also employ a gravel-optimized body shape cross-section for seamless integration with flared handlebars. Rounder in shape, the transfer from handlebar to hood is smoother and creates a larger surface area to help eliminate pressure points. With enhanced comfort, you can extend your day out.
Included Components:
- Chainset: Shimano GRX RX820 Double 12spd (choose size)
- Cassette: Shimano 11-34 Ultegra CS-R8101 or 11-36 105 CS-HG710 cassette
- Front STI/Brake: Shimano ST-RX825 GRX Di2 12-Speed STI Bled with BR-RX820 Calliper Right Front
- Rear STI/Brake: Shimano ST-RX825 GRX Di2 12-Speed STI Bled with BR-RX820 Calliper Left Rear
- Rear Derailleur: Shimano RD-RX825 GRX Di2 12-Speed Rear Derailleur Shadow+ max 36T for Double
- Front Derailleur: Shimano FD-RX825 GRX Di2 Front Mech 12-speed Double Braze-on
- Chain: Shimano CN-M8100 XT/Ultegra 12 Speed 126L Chain
- Battery: BATT Di2 DN300 Internal one size
- Charging Cable: Shimano Steps EW-EC300 Di2 Battery Charging Cable 1700mm
- Electric Wire: Shimano EW-SD300 E-Tube Di2 Electric Wire (2 units 900 & 1400mm)
Full Specification:
- Series: Shimano GRX Di2 RX825
- Speed: 12-speed
- Shifting Platform: WorldTour-proven Di2 electronic shifting
- Gearing Options (Crank): 48/31T RX820 crank or 46/30T RX610 crank
- Gearing Options (Cassette): 11-36T HG710 cassette or 11-34T R9200, R8100, R7100 cassettes
- Power Supply: Central, multi-port battery (wired connection to derailleurs)
- Rear Derailleur Technology: SHADOW RD+ (with on/off switch for wheel removal and chain tension)
- Chainline: Wider, +2.5mm chainline for improved tyre clearance
- Cockpit Features: Wireless, raised hoods with ribbed surface texture, anti-slip brake levers
- Di2 Levers: Include a third Di2 button on the inside of the hood (assignable function)
- Additional Shifting: Allows for accessory satellite shift buttons (assignable functions)
- Lever Shape: Gravel-optimized body shape cross-section for seamless integration with flared handlebars