With Shimano's GRX component line-up currently the only remaining of Shimano's major groupsets stuck on 11 speed (Dura-Ace, Ultegra, 105, XTR, XT, and SLX are now all 12 speed) it's probably not a huge secret that an updated GRX group is coming.
What's less certain, however, are the details of what a refreshed GRX might look like. Some of those changes are a foregone conclusion - it doesn't take a genius to speculate that the new group will be 12 speed, for example - but others are more of a maybe.
GRX is used for a huge variety of riding styles, including pro and amateur cyclocross, gravel riding and racing, off-road bikepacking and loaded touring. Each of those groups wants something different from GRX. My perspective is from the owner of "one bike" I use for cyclocross racing plus training on both paved and unpaved surfaces. I've divided my thoughts into 3 sections: sure thing, maybe, and unlikely.
An updated Shimano GRX group - the sure things
There are a couple slam dunks when it comes to looking ahead to a future GRX group:
GRX is almost certain to be 12 speed in the future
This one's a lock. The current GRX has been left behind, stuck in 11 speed land while Shimano's other top-tier groups (Dura-Ace, Ultegra, and 105 on the road side, XTR, XT, and SLX on the MTB side) have all moved on to 12 speed.
Moving GRX to 12 speed will bring better parts interchangeability and consistency. Bet on it.
GRX Di2 will adopt the wireless Dura-Ace, Ultegra, 105 system design
The current 11 speed GRX components come in a mechanical and an electronic ("Di2") option. The Di2 electronic implementation is the "classic" Di2 with physical wires running from the shifters to a junction box, and then to the battery and derailleurs.
Shimano's 12 speed road groups, in contrast, use a new, refreshed version of the Di2 electronic shifting system, in which the shifters are wireless, with no cable or wire running between the shifter and derailleur. Instead, both derailleurs are connected internally by wiring, as well as to a hidden (usually seat post) battery, and that system talks to the shifters wirelessly, with the shifters being powered by small coin-style batteries instead of the "primary" battery that powers the derailleurs.
The "maybe" category for an updated GRX group
GRX 12 speed might keep a mechanical group option, in addition to electronic
Shimano's R7100 105 (as well as the Dura-Ace R9200 and Ultegra R8100 parts that were introduced previously) road components are electronic only - no mechanical shifting option is offered for sale. It's possible a refreshed GRX group could go in that direction, but it's also possible that Shimano would keep making both a mechanical and electronic shifting Di2 GRX 12 speed option.
A case can be made that GRX users do extended tours, especially off-road bikepacking, during which no reasonable battery recharging option exists. Even though the batteries on a Di2 bike last for a very long time, mechanical drivetrains with physical cables that can be serviced in the field might be desirable for this type of rider. What's uncertain is whether there is enough demand to produce both electronic and mechanical groups.
Bigger cassettes and a rear derailleur with more capacity
The current 11 speed GRX rear derailleurs for mechanical and Di2 drivetrains comes in two options - a version that accommodates a max cassette cog of 42 teeth with a total capacity of 31 teeth (intended primarily for single chainring drivetrains) and a version with a max cassette cog of only 34 teeth, but with a larger capacity of 38 teeth (Di2) and 40 teeth (mechanical version), which is designed to be used with a double crankset.
No matter how long the "official" gear offered is, there's always a rider looking for even more - people with knee injuries, riders who ride steep terrain while carrying camping gear, or just riders who aren't in the shape they used to be. To accommodate such riders, we could see even lower gear ratios possible.
12 speed Shimano GRX - unlikely predictions
As much as I would hope for these to come true, they're unlikely to come to fruition:
Silver components
Shimano made some special one-off silver GRX components under the label "GRX Limited". I love the classic throwback look of the silver GRX parts!
Will we see them in production when the new 12 speed gear hits? It seems unlikely. If you're in love with the silver look, there are some GRX silver 11 speed parts still in channels.
Mixing and matching MTB Di2 components into a Di2 group
Some mix-and-match has been possible between road and MTB Di2 components. For example, you can use 11 speed GRX Di2 electronic shifters in a 1x (single chainring) drivetrain with an XTR (MTB) Di2 rear derailleur. A rider might want to do this who wants a larger cassette cog than the GRX Di2 rear derailleur can accommodate.Unfortunately, this only works in 1x single chainring applications. If you want a double GRX crank, you need the GRX Di2 front derailleur, which can't in turn be used with the XTR Di2 rear derailleur. Confused yet?
Don't expect this to change with a future GRX Di2 12 speed group.
Single-chainring 1x only; with no double crankset option
SRAM's XPLR line of components is SRAM's answer to Shimano's GRX... er, maybe it's vice-versa? Regardless, these two groups go head to head and compete for marketshare. XPLR is single chainring only, with SRAM heavily invested in the 1x setup. Shimano, in contrast, continues to offer a GRX front derailleur and double crank for riders who want it.I think Shimano dumping the double crank is unlikely, so I've listed it here in my "unlikely, but possible" section.
There you have it - my predictions for a new, updated Shimano GRX. We'll check back following the inevitable launch to see how accurate I was.