“SHIMANO marks its debut in the fully wireless drop bar segment with the new 1×12-speed GRX Di2 gravel-specific components. Leveraging the wireless cockpit introduced with SHIMANO’s 2×12 speed road and gravel groups and incorporating the completely wireless technology debuted on the M9200-series XTR rear derailleur, GRX RX827 features a fully wireless drivetrain designed for performance, durability, and versatility. With RX827, the GRX lineup now includes a comprehensive range of mechanical and electronic shifting options in both 1×12 and 2×12-speed configurations, allowing riders to tailor their drivetrains for their unique gravel riding demands.” – Shimano Gravel
Shimano GRX Di2 1×12-Speed Goes Wireless Video
Alternative Video Link for those reading via email subscription
In this video, JOM of the Gravel Cyclist provides a detailed look at the components of Shimano’s new fully wireless GRX Di2 1×12-Speed, building the groupset, and first rides and impressions. Long term review of Shimano GRX Di2 1x 12-Speed coming later!
“GRX RX827 is designed to be close to the rider, offering the freedom to choose without being tied down. With no special frame requirements, it can be easily installed on any gravel bike you own. This allows you to upgrade your favorite bike with the latest technology and take it on even more adventures.”
“Centered around the RD-RX827 wireless rear derailleur, GRX 1×12-speed brings unmatched chain management and precise shifting to gravel riders. The new system is engineered for seamless performance across varied terrains, whether racing, exploring backroads, or embarking on all-day adventures.”
SHIMANO GRX 1 x 12-Speed Key Features
- Fully Wireless Di2 Platform – Designed for ultimate reliability, the wireless Di2 system offers fast, precise shifting and compatibility with all SHIMANO 12-speed wireless shifters (GRX, DURA-ACE, ULTEGRA, SHIMANO 105 Di2 drop bar options, as well as XTR and DEORE XT flat bar Di2 models).
- Robust Gravel Drivetrain – Borrowing its design from SHIMANO’s MTB Di2 line, the RX827 rear derailleur features the same low-profile design, skid plate, protected battery, and automatic impact recovery function.
- Refined Ergonomics – Enhanced grip, clean cockpit design, and unparalleled customization for superior handling and comfort.
- Expanded Versatility – Added GRX component options allow riders to optimize performance based on terrain, style, and personal preferences.
Wireless GRX Shifting
The new GRX 1×12-speed drivetrain pairs the RD-RX827 wireless rear derailleur with SHIMANO’s existing RX825 Di2 DUAL CONTROL LEVERS, RX820 crankset, brakes, and XT 10-51T cassette. This combination delivers SHIMANO’s hallmark Di2 performance in a sleek, robust 1×12-speed package.
Riders can choose between 40T or 42T chainrings and pair them with SHIMANO’s line of 10-51T MICRO SPLINE cassettes. Similarly, RX827 offers an electronic option for drop bar mountain/adventure bikes that utilize mountain bike crank standards. Whether climbing steep trails or cruising flat stretches, the GRX system adapts to any riding style or terrain.
SHIMANO SHADOW ES Rear Derailleur
The GRX RX827 rear derailleur, with new SHIMANO SHADOW ES technology, is offered in a single SGS long-cage spec and was built for durability and functionality. The derailleur features a low-profile wedge design, and the chain stabilizer unit blends seamlessly into the body to minimize exposure to impacts. By eliminating sharp edges on the derailleur, it’s able to glance off obstacles and handle most rock impacts when the gravel trail gets rugged.
When inevitable impacts do happen, the derailleur absorbs this force. Then, SHIMANO’s automatic impact recovery function instantly returns the derailleur to its original position. Often, the GRX RX827 rider will never know there was a rock strike.
The wide link structure, durable plate, skid-plate design, and solid pulley further enhance the derailleur body’s survivability, ensuring continued performance through rough and muddy conditions.
Rear Derailleur Technology Features
- Low Profile Design – SHIMANO SHADOW ES technology delivers a wedge-shaped design that reduces the derailleur’s front-facing surface area and eliminates edges that could catch on rocks and road debris.
- Automatic Impact Recovery Function – The derailleur absorbs impacts and then automatically resets the rear derailleur, ensuring continued performance.
- Super Strong Design – The rear derailleur body boasts a wide, well-braced linkage and solid pulleys to minimize debris entry and ensure durability.
- New Chain Stabilizing Technology – The dual spring design creates higher chain tension for better chain wrap and retention.
- Battery Protection – Tucked safely inside the rear derailleur body, the sealed battery won’t budge even in the roughest terrain but is still easily removed for charging.
RD-RX827 – Wireless Rear Derailleur
- SHIMANO SHADOW ES Technology
- Precise wireless shifting
- Robust structure with skid plate design
- Solid pulley construction
- Removable and rechargeable onboard battery
- 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 cassettes
- 449 grams
Gravel Cockpit Addition
BL-RX825-L – Hydraulic Disc Brake Lever
- 1×12-speed brake lever option
- Gravel-specific brake lever and bracket ergonomics
- Flared drop bar optimization
- Anti-slip coating on brake lever surface
- 19.5 grams lighter (188 grams for BL-RX825-L versus 207.5 grams for ST-RX825-L)
Advanced Di2 Button Functions – Shifting Versatility
Whether utilizing the new BL-RX825-L brake lever or sticking with a pair of GRX ST-RX825 DUAL CONTROL LEVERS, Shimano 1×12-speed GRX delivers a variety of shifting possibilities thanks to Di2’s customizable buttons as well as add-on accessory switches.
Carried over from previous generations, the GRX RX825 DUAL CONTROL LEVERS feature three Di2 buttons – two buttons are located on the shift paddles while a third button is found on the inside of the hood. The RX825 levers also allow for accessory shift buttons, which can be placed on the tops, drops, or aero bars for additional shifting options.
Each Di2 button mentioned above can be assigned various functions, including shifting the rear derailleur, controlling compatible lights and cycle computers, or it can be used as a remote function button for the rear derailleur. With this last option, riders can make shifting trim adjustments on the fly without taking their hands off the handlebars.
Long-Term Review Coming Later!
Learn more at the Shimano Website