New Shimano GRX 12 Speed Mechanical Gearing

October 05, 2023

Shimano introduces new Unbeatable, Unstoppable and Undroppable gravel groupsets

Shimano has released the latest addition to their new GRX gravel bike groupset lineup. For now, it's just mechanical but has gained 12-speeds and finally offers broader gearing choices closer in competition to SRAM.

Currently, GRX is introduced only as a mechanical version, with no word on the inclusion of Di2. However, we’re hoping on this emerging down the line.

The advanced new GRX RX610, positioned below the RX820, has also transitioned to a 12-speed setup. It continues in both dual (2x) and single (1x) options, incorporating innovations from the original GRX 800 series.

Both the new GRX models are segmented into three categories: Unbeatable, Undroppable, and Unstoppable. These classifications help in distinguishing there configurations: a 1x for competitive gravel racing, a 2x for versatile gravel riding, and a 1x mullet drivetrain for bike packing.

In addition, Shimano has refined their gravel wheel. The carbon RX880 wheel now boasts a 32mm-deep rim with a 25mm inner dimension, making them ideal for gravel tyres with widths ranging from 32mm to 50mm.

Key overview

Exclusively mechanical with hydraulic disc braking
Both single (1x) and double (2x) setups offered
Three distinct options – Unbeatable, Undroppable, and Unstoppable
The 1x configuration is equipped with a 10t sprocket adopting the MTB Micro Spline freehub
Cassette options for 1x range between 10-45t and 10-51t
RX822-GS and SGS derailleurs feature swappable cages
The advanced RX610 version includes 12-speed, offering both 1x and 2x configurations.

New shifter ergonomics and brakes

The design of the shifters has been revamped to align better with flared bars, a frequent feature on gravel bikes. The new hood showcases a contoured design, spreading pressure across a broader area of your palm for sustained riding comfort.

GRX brake levers feature a sturdy anti-slip finish, guaranteeing improved grip and command even during intense rain or muddy situations. Shimano has integrated fishing equipment technology into the new brake levers, using a unique rough-textured material originally designed for better grip on wet fishing rods. This adaptation aims to enhance rider confidence on gravel terrains, especially in adverse weather.

Shimano has also refined the shifter body's contact point with the bar. This modification aims to enlarge the hand pressure's effective surface, thus minimizing potential hand discomfort.

Updated gearing options

Shimano has broadened its GRX gearing choices, catering to both the 1x and 2x setups.

For 1x systems, cassette options now encompass a wider 10-45t and 10-51t. Meanwhile, 2x configurations can opt for the conventional 11-34t or 11-36t cassettes.

Previously, the broadest 1x cassette was only 11-42t, which didn't quite measure up to SRAM's gear range of 10-52t.

Shimano's latest GRX 10-45t and 10-51t cassettes are harmonious with the current mountain bike gear sets, which entails adopting the Micro Spline freehub for 10t sprockets. Meanwhile the 11-34t or 11-36t cassettes align with the HG L2 freehub norm for Shimano's 12-speed road cycling sets.

Unbeatable, Undroppable and Unstoppable?

The new lineup consists of the Unbeatable, Undroppable, and Unstoppable variations.

The Unbeatable focuses on a 1x drivetrain optimized for gravel racing, Undroppable is geared towards all-terrain 2x gravel riding, and the Unstoppable boasts a 1x drivetrain with a broad mullet gear range for bigger adventures.

Shimano GRX RX820 Unbeatable

Shimano's GRX RX820 Unbeatable, is geared towards gravel racing, a 10-45t cassette with either a 40t or 42t 1x chainring. Shimano claims that competitors seeking to break their own records or compete intensely would favor the gear setup of the Unbeatable. The new cassette range has made it slightly broader than SRAM’s XPLR 10-44t option. Shimano guarantees smoother shifts with the Unbeatable and a quieter ride, especially on rugged terrains, with the new Shadow RD+ chain stabilizer.

Shimano GRX RX820 Undroppable

The 2x version of GRX is dubbed ‘Undroppable’. Its equipped with a gravel-focused 48/31t chainring combo, combined with either an 11-34t or 11-36t cassette.

While single-chainring (1x) gravel bike groupsets are gaining traction, they lead to wider spacing between gears, which in some situations is less efficient.

The RX820's rear derailleur boasts the shortest cage, accommodating cogs up to 36t in size. It is also equipped with the advanced Shadow RD+ clutch system to prevent chain slap and drops.

To accommodate broader tyres, the new front derailleur alignment has moved outward by 2.5mm compared to traditional road bike front derailleurs.

Shimano RX820 Unstoppable

Shimano's GRX RX820 Unstoppable offers a genuine mullet drivetrain, amalgamating the new RX822-SGS rear derailleur with an XT M8100 10-51t cassette. This is what we’re most excited about.

While SRAM groupsets have better interchangeability, Shimano's different pull ratios for MTB and gravel derailleurs made combining these existing platforms not possible.

Shimano's new derailleur cage can be interchanged with the Unbeatable version, allowing Unbeatable and Unstoppable setups by merely switching the derailleur cage, cassette, and chain.

Shimano also enhances its dropper post lever offering, integrated into the left-hand shifter for 1x configurations, making it compatible with a wider range of dropper posts.

Shimano's GRX RX610 Groupset Overview

Shimano's GRX RX610 groupset completes the gravel lineup. The RX610 offers a more wallet-friendly alternative.

Still available in both 1x and 2x configurations, the 1x variant offers choices between 38t or 40t chainrings and is compatible with 10-45t or 10-51t M7100 cassettes.

The 2x version is equipped with 46/30 chainring combo, delivering a slightly narrower range with an 11-34t or 11-36t cassette at the higher end.

Some features are excluded with the RX610. The groupset has a more straightforward shifter design, excluding Servo Wave and the dropper post feature. This means you won't find an integrated dropper post lever in the RX610 range.

New GRX RX880 Carbon Gravel Wheels

Shimano doesn't disappoint, updating their gravel wheel arsenal. The RX880 hubs utilize the updated DIRECT ENGAGEMENT technology, inspired by DURA-ACE wheels, ensuring swift and efficient responsiveness for acceleration across all terrains. The hub design allows for the installation of either an HG+ or a Micro Spline freehub. 24H J-bend spokes, guaranteeing dependability during demanding expeditions.

The rims are tubeless compatible, featuring a hooked rim suitable for tyre widths between 32-50mm. Claimed weights are, for Micro Spline freehub 1,394g, whereas HG+ is 1,397g.