Shimano Goes Gravel With GRX Component Group

In another sign of the popularity of gravel riding, Shimano has released a new line of drivetrain components called GRX. The new product line looks to fill the same role for Shimano as Apex and Force CX1 has for SRAM, but are not considered full groupsets.

The new GRX line is dedicated to gravel, cyclocross, adventure riding, bikepacking, and so on. Offered in three levels, RX400 (Tiagra 10 Speed), RX600 (105 11 Speed) and RX800 (Ultegra/Ultegra Di2 11 Speed), it can be configured a 1×11, 2×11, and 2×10, mechanical or electronic. The only choice you don’t have is brakes, as GRX is hydraulic disc brake only.

The GRX lines are primarily made up of cranksets, front and rear derailleurs, shift levers and brakes, and wheels. Cassettes, chains, and other parts will come from the road and mountain groups.

Cranks

The GRX cranksets are offered in 1x and 2x options. Both use a four bolt pattern for their rings, with the 1x version using Shimano’s Dynamic Chain Engagement tooth profile in conjunction with their clutch Shadow rear derailleurs to hold the chain on in bumpy conditions. The chainline is moved out by 2.5mm to allow for greater clearance for wider frame clearances for wider tires. Double cranksets will be available in 48/31 and 46/30 for the RX800 and RX600 (11 and 10 speeds). 1x cranksets will be part of RX800 and RX600. No cranks are currently announced for the RX400 level.

Front Derailleurs

The front derailleur follows the crankset with an additional 2.5mm of spacing for additional clearance for larger tires. Shimano says you can stuff up to a 42mm wider tire in back and still use a front derailleur. This also means though, that you have to use GRX front derailleurs and cranks together if you are going double. They can handle up to a 17 tooth difference between chainrings. They will be available in RX800 and RX400 levels in braze-on mounts.

Rear Derailleurs

The heart of the rear derailleur is Shimano’s Shadow RD+, which brings the clutch system from the trail to the road. Shimano already did this with their Ultegra RX line, but the GRX lines add Di2 and 10 speed options. As with SRAM’s 1x and 2x derailleurs, GRX derailleurs are 1x or 2x specific.

The RX800 come in long and medium cage, while RX400 is medium cage only. Long cage models are rated to work with 11-40 and 11-42, while the medium cage is suited for 11-30 and 11-34, or 11-30 and 11-36 for RX400.

STI Levers

Here is where things get fun. The GRX STI shift/brake levers are all new. The shape has been redesign for better grip and ergonomics off road. The pronounced bump caused by raising the pivot point higher in the lever, should provide a more secure grip when things get rough. From the side, the GRX lever has more of a vertical bump than a forward bump of traditional Shimano road levers. Some might not like the look, but think about how the original SRAM Hydro levers were received. They were polarizing, but many riders like the additional hand position and security that they provide, myself included. The blades also have a more pronounced curve to them, allowing you to hook your fingers in. Add in a new textured feel on both the hoods and the blade, and you have the making of a very secure platform.

Inside, there are some new surprises as well. RX800 mechanical users will benefit from Shimano’s ServoWave system, another crossover from the mountain bike world. Instead of a linear pull on the brakes, the ServoWave quickly moves the pads to contact the rotors. Further along in the stroke, the brakes transition to higher power and modulation.

1x users will also benefit from a hack that some have done with SRAM 2x shifters. Since you have a free lever on the left, why not put it to use as a dropper control. I’m currently running this hack on a SRAM system, but it required some modifications to the internals to remove the ratchet. Shimano’s RX800 level left shifters are available with a lever to control a front derailleur or their ASP dropper posts, or without a lever for those looking for a clean look. Di2 users can run a Di2 right to control the rear derailleur, mechanical left lever to handle dropper duties, or a lever free unit for a clean 1x look.

Old school cross riders can rejoice as well. Shimano will be offering bar top brake levers for those who are missing them since trading mechanical rim brakes for hydraulic disc brakes. Details are limited at the moment, but Shimano looks to be the first brand with a factory option for inline brakes. Hope teased a possible option a few years back, but it never made it into full production. We have heard that they will be compatible with previous Shimano hydraulic road levers, but we will clarify as more details become available.

Disc Brake Calipers

Nothing really new here. The GRX edition calipers are rebadge flat mount road brakes.

Wheelsets

To round out the GRX line up, Shimano has included a couple wheel sets that go wide to accommodate the wider tires that GRX users will typically use. The aluminum rims have a 21.6mm internal width and a shallow 22mm height. They will be available in 700c and 650b, and as all wheel set should be these days, they have a tubeless inner profile. The hubs come set up as 12mm thru-axle, though 15mm and quick release plugs will most likely be available. Discs will mount on Shimano’s CenterLock standard, and the wheel sets are 24 spoke front and rear for durability.

Pricing and Availability

If you want to get your hands on a GRX set up for your gravel build, the mechanical versions should be available in June and July. Di2 should start to hit stores in August. See below for pricing info.

Cranks

RX810 1x (655g) – $225
RX810 2x (722g) – $225
RX600 1x (753g) – $147
RX600 2x (816g) – $147
RX600 1×10 (819g) – $147

Front Derailleurs

RX815 Di2 (131g) – $227
RX810 Mechanical (94g) – $52
RX400 Mechanical (95g – $37

Rear Derailleurs

RX817 Di2 1x (322g) – $320
RX815 Di2 2x (288g) – $287
RX812 Mechanical 1x (264g) – $114
RX819 Mechanical 2x (251g) – $112
RX400 Mechanical 2x (303g) – $63

Shift Levers

RX815 Di2 Shift Lever Set (TBD) – $534
RX810 Mechanical Shift Lever Set (565g) – $534
RX600 Shift Lever Set (611g) – $410
RX400 Shift Lever Set (613g) – $330
Dropper Post Lever (TBD) – $245

Brake Levers

RX812 Sub Brakes (TBD) – $66
RX810 Left Brake Lever 1x (TBD) – $215
RX600 Left Brake Lever 1x (TBD) – $185

Brake Calipers

RX810 Flat Mount Front (TBD) – $82

RX810 Flat Mount Rear (TBD) – $76

RX400 Flat Mount Front (TBD) – $61

RX400 Flat Mount Rear (TBD) – $55

Wheels

650B Tubeless Front (TBD) – $198
650B Tubeless Rear (TBD) – $225
650B Tubeless Set (TBD) – $420
700C Tubeless Front (TBD) – $198
700C Tubeless Rear (TBD) – $225
700C Tubeless Set (TBD) – $420

http://bike.shimano.com