Shimano has expanded its range of gravel components with the launch of GRX RX825 12-speed Di2. With Shimano’s Dura-Ace, Ultegra and 105 road groupset firmly in the 12-speed Di2 realm, the Japanese giant’s gravel-specific GRX line found itself at a crossroads after launching the mechanical GRX RX820 12-speed group last August. as the electronic GRX still had 11 gears. That’s no more, though, as the new 12-speed GRX Di2 gets wireless shifting and redesigned shifters. However, it is currently only compatible with a 2x setup.
Last year, Shimano released the long-awaited GRX 12-speed mechanical groupset. After much speculation, it has now (perhaps inevitably) unveiled the electronic-shifting version, which Shimano says delivers “precise, reliable and distraction-free performance in all conditions”.
Wireless switching
The first major design change to the new 12-speed GRX Di2 is wireless shifting. An electronic GRX group already exists, but it is an 11-speed version with a wired connection box on the handlebar/stem.
> New patent suggests Shimano 13-speed electronic groupsets are coming
Like its 12-speed Dura-Ace, Ultegra and 105 Di2 street-specific siblings, the new GRX Di2 system is semi-wireless with a central internal battery and wireless shifting.
Wireless shifting eliminates the need for a wired junction box on the handlebar/stem, and the shifters communicate wirelessly with the derailleurs. Wireless means fewer cables need to run through the frame, which is especially useful on modern racing bikes.
Redesigned switches
The brake and shift levers are the heart of the Di2 system, allowing you to control both the derailleurs and the hydraulic brakes.
Shimano’s 12-speed GRX Di2 features dual control levers, each equipped with three Di2 buttons for E-Tube project adjustment (more on this below). The third button is located at the top of the shifters, on the inside, in a similar location to the new SRAM Red AXS.
These dual control levers feature a redesigned rounder shape, a refinement aimed at creating a smoother transition from handlebar to hood and ensuring seamless integration with flared handlebars, according to Shimano.
Like all Shimano Di2 shifters, they operate on replaceable button cell batteries, with an expected lifespan of 3.5 to 4 years.
Satellite shifting
Shimano’s new Di2 system also allows for additional shifting buttons. Shimano satellite shifters can be placed anywhere on your bike’s handlebars, allowing you to shift gears faster during exercise without having to move your hands.
Shadow RD+ rear derailleur
Like Shimano’s mechanical RX820 rear derailleur, the RX825 rear derailleur features Shimano’s Shadow RD+ technology, which is designed for safer chain management during rough rides.
It has an on/off switch that makes it easier to remove the rear wheel when it is turned off. When engaged, “the drivetrain is under additional stress, providing a quieter ride and more precise shifting,” according to Shimano.
As with all Shimano’s 12-speed Di2 road systems, the rear derailleur also houses the charging port and multi-function button so you can check battery levels.
E-Tube project customization
‘E-Tube Project Cyclist’ is Shimano’s app that allows you to customize your electric shifting. Whether that is for controlling the shifting of one of the derailleurs, or for scrolling through screens on your bicycle computer.
> Your complete guide to Shimano road bike groupsets
The launch of Shimano’s 12-speed GRX Di2 groupset also coincides with the new Front Shift Next functionality, implemented via a firmware update. Via the E-Tube Project Cyclist app you can program any Di2 button to switch the front derailleur to the chainring you are not currently using, and vice versa. This update also applies to all Shimano 12-speed Di2 road groupsets.
Shimano 12-speed GRX Di2 prices
Obviously you’re interested in what all this new 12-speed Di2 GRX stuff is going to cost, right?
There are a number of components shared between the mechanical RX820 GRX and Di2 RX820 groupsets, with the crankset, chain, cassette and brakes all being the same whether you opt for cables or wires.
As with the mechanical components of the RX830, you can also use the RX610 cranks and the 46/30T chainrings.
Here are all the individual component prices you need to know:
825 series shifter and disc brake kit
- RX825 GRX Di2 12-speed STI bleed with RX820 caliper, right front – £399.99
- RX825 GRX Di2 12-speed STI bleed with RX820 caliper, left rear – £399.99
825 series shifters only
- RX825 GRX Di2 12-speed STI – £299.99 each
825 series derailleurs
- Rear derailleur RD-RX825 (max 36T for double) with Shadow+ tech (310g) – £324.99
- Front derailleur FD-RX825 brazed 2×12-speed (142g) – £184.99
Cassette and chain options
- The 11-34T cassette is £119.99 and the 11-36T cassette retails for £84.99
- CNM8100 with Hyperglide technology – £49.99
RX820 series components
820 series chain sets
- The double chainsets are available with 170mm, 172.5mm or 175mm cranks and 48/31 chainrings (710g) and available for £229.99
820 series brake calipers
- BR-RX820 GRX flat-mount caliper with adapter 140/160 mm front – £79.99
- BR-RX820 GRX flatmount brake caliper without rear adapter – £74.99