Shimano GRX drivetrains are gaining another gear, bringing the gravel group in line with the brand’s MTB and road groups which both offer 12-speed cassettes. This is especially welcome news for 1X gravel riders who are now able to access a larger, 52T cog and smaller 10T cog in the rear.
Options, options
Like the previously available 11-speed GRX groups, the 12-speed GRX system borrows cassettes from the mountain bike line. The new long-cage 12-speed GRX rear derailleur fits a Shimano M8100 10-52T cassette which is the same one used by the XT mountain bike group. For riders looking for a more graduated gearing range, there’s also the option of a 10-45T cassette. Presumably the lower priced SLX and Deore Hyperglide+ cassettes should be compatible too, though Shimano does not explicitly confirm this in press materials for the launch.
GRX shifters and derailleurs have been updated to click through 12 speeds, though it seems the look and feel of both remain much the same as before. The new 12-speed shifters and derailleurs are available at the high-end, RX820 level and also a more value-oriented RX610 level. Di2 12-speed derailleurs were not announced at this time.
One-by GRX cranksets are available with 40T and 42T chainrings as before, and in 170, 172.5, and 175mm lengths. Buyers can also assemble a 2×12 drivetrain which pairs a 31/48T double-ring crankset with a front derailleur and up to a 11-36T cassette.
GRX carbon wheel update
The new Shimano RX880 carbon wheelset is said to be 64g lighter than the previous carbon GRX wheels. Shimano is employing their “Direct Engagement” hub design on the GRX wheels which makes it easy to swap between a Microspline and HG driver. The updated GRX carbon rims use the same 25mm internal rim width as before which is optimized for 32-50mm wide tires.
