Gravel Grinder News: 12-Speed Shimano GRX Found Hiding in Plain Sight at Unbound Gravel

Gravel Grinder News: 12-Speed Shimano GRX Found Hiding in Plain Sight at Unbound Gravel – by MG

It’s been a full three years since Shimano introduced its groundbreaking GRX gravel groupset, so I figured something new was in the works. However, I had no concrete proof until I literally stumbled onto it while in Emporia for the Gravel Cycling Hall of Fame induction ceremony this past Wednesday.

As I was walking around the neighborhood just outside downtown, I saw a Ventum gravel bike in a driveway that looked as if it was in the middle of being cleaned and lubed. It had what looked to be a ‘typical’ GRX 1x drivetrain setup, however as I drew closer, I noticed the GRX logo on the derailleur was different than the current 11-speed group.

My interest piqued, I quickly counted the number of cogs on the cassette. There were twelve of them, and the overall configuration reminded me of Shimano’s current 12-speed mountain bike drivetrains. That said, the cassette looked to have smaller jumps between the gears, particularly on the larger cogs.

I had enough time to shoot a few shots before the person working on the bike came out the back door, at which time I quickly pocketed my phone, said “nice bike” and went on my merry way. Whew, that was close…

So, without further ado, here’s a pictorial summary of what I found:

New GRX spy shot 1
From the front, the bike didn’t give much away, aside from a switch from a silver accent to black at the top of the STI shift/brake lever blade. Wheels appear to be standard GRX Carbon models.
GRX Spy Shots 2
The GRX crank looks to be a similar format to the existing 11-speed model, presumably with a change to a 12-speed compatible chainring. Look at the difference between the two chainring tooth profiles. Chain retention shouldn’t be any problem.
New GRX spy shots 3
The rear derailleur was my first clue that this wasn’t current generation GRX. Not surprisingly, the derailleur configuration looks to closely mimic Shimano’s most excellent 12-speed MTB derailleurs. The chain also looks to be a standard Shimano 12-speed XTR/Dura Ace model.
New GRX Spy Shots 4
Count ’em: 12 cogs. I didn’t have time to look closely at the cassette, but it looks very similar to Shimano’s existing 12-speed MTB gear range (10-51t). That said, it could be a slightly tighter cog stack. Time will tell…

At this point we have no information other than what we can glean from these images, which create as many questions as they do answers. Will Shimano continue to offer GRX in a 2x format? Is that a 10t small cog (like their MTB groups), or a 11t cog (like their road groups)? Does it use a standard HG cassette driver, or a Micro Spline driver like the MTB groups? What about GRX Di2? When will we be able to get our hands on it? All those questions and more will be answered in due time. I just don’t have any clue when that’ll be.

So for now, I’m just stoked to see that Shimano is continuing to invest in GRX and gravel-specific drivetrains. To me, that says they see gravel continuing to grow and proliferate, and that’s a very good thing.

Have a great weekend and best of luck to everyone in Emporia tackling Unbound Gravel tomorrow!!


Author: MG

Matt Gersib is the 2014 Gravel World Champion in the Fatbike category. He's also finished some of the most challenging gravel events in the country, including the Dirty Kanza XL, TransIowa and the Dirty Kanza 200, among others. In 2015, Gersib was an inaugural inductee into the DK200 "1,000 mile club" of five-time finishers. In addition to his gravel cycling, Gersib is an accomplished mountain bike racer, with numerous race wins and championships, including the 2012 Nebraska State Marathon MTB Championship.

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