Shimano GRX | Dedicated group for Gravel bikes

Shimano GRX is a series of components specially designed and dedicated to bicycles:

• gravel
• expedition / adventure
• cyclo-cross

Shimano GRX group offers several possible configurations. These include 10 and 11-speed cassettes and cranks with 1x and 2x chainrings, as well as Di2 electronic shifting capability.

If you’re wondering whether Shimano GRX is a completely new component group created from scratch, the answer is no. Shimano GRX is a group whose components were largely created by combining solutions from road and mountain bikes, and adding some completely new parts.

Shimano GRX is divided into three basic subgroups:

• RX800 – 11-speed kit at Shimano Ultegra level – available in mechanical and electronic (Di2) configuration
• RX600 – mainly an 11-speed kit at the level of the Shimano 105, but a 10-speed kit is also possible – available in a mechanical configuration
• RX400 – Shimano Tiagra level 10-speed kit – available in mechanical configuration

The division into three subgroups seems straightforward, but in reality not every group contains all the components with a given designation. For example, in the RX600 group there is no rear derailleur and it must be selected from another series.

If you’re at the beginning of your journey with gravel bikes and are still getting lost in the various configurations, we recommend that you try checking out the various available configurations of these groups yourself on Shimano’s website, or take a look at the Shimano GRX component configuration chart below.

The above diagrams perfectly illustrate why it is accepted that it is easier to express the configuration of the Shimano GRX group in the following way, depending on individual needs:

• Shimano GRX 11-speed Di2
• Shimano GRX 11-speed
• Shimano GRX 10-speed

Shimano GRX does not have its own dedicated chains, so you will select from such existing Shimano chains as:

• Ultegra
• 105
• Tiagra
• XT
• SLX
• Deore

Let’s now move on to chainset configuration, which comes in three options:

• 1×11 – GRX 800, GRX 600
• 2×11 – GRX 800, GRX 600
• 2×10 – GRX 600

“Pinarello Grevil+ with Shimano GRX Di2 and Enve cockpit and wheels.” by Glory Cycles is licensed under CC BY 2.0.

“Pinarello Grevil+ with Shimano GRX Di2 and Enve cockpit and wheels.” by Glory Cycles is licensed under CC BY 2.0.

“Pinarello Grevil+ with Shimano GRX Di2 and Enve cockpit and wheels.” by Glory Cycles is licensed under CC BY 2.0.

In the table below you will find the exact specifications of the individual cranks and chainrings in the Shimano GRX group:

The most important difference between the RX600 and RX800 groups is the latter’s use of Shimano’s Hollowtech II technology, which best balances stiffness, strength and provides a lightweight component. It is also worth noting at this point that Shimano uses a Dynamic Chain Engagement tooth profile on its cranks with single ring chainsets (1x), which prevents the chain from falling off in rough terrain.

For the Shimano GRX front derailleur you have a choice of mechanical (RX810, RX400)or electronic (RX815) derailleurs.

The difference between these and road derailleurs is that those in the GRX family have the chainline moved 2.5mm outwards so your gravel bike can accommodate wider tyres with more aggressive tread. This is what sets them apart from Shimano’s road front derailleurs, for example. This is also one reason why matching chains must be used for Shimano GRX front derailleurs.

Note also that the Shimano GRX derailleurs – both the RX810 and RX815 handle and satisfy the 17-tooth difference between the RX810-2 crank chainrings, while the RX400 derailleur satisfies the 16-tooth difference between the RX600-11 and RX600-10 crank tops.

In the table below you will find the exact specifications of the individual Shimano GRX derailleurs:

Shimano GRX rear derailleurs are available in mechanical and electronic versions. All of them use Shimano Shadow RD+ technology, which is designed to stabilise the chain and provide quiet, precise and reliable gear / derailleur changes over varied terrain. What’s more, the adjustable chain stabiliser prevents the chain from bouncing and falling off.

Each Shimano GRX rear derailleur also features a stabiliser on/off switch, which allows you to alter chain tension and minimise chain bounce.

An important feature of Shimano GRX rear derailleurs is that they are positioned deeper under the cassette than Shimano’s road rear derailleurs. This means that their outer extension beyond the frame on the smallest sprockets is as far as it goes on road derailleurs. This makes the equipment less likely to snag on any obstacles when navigating difficult terrain.

“Shimano GRX Di2 Rear Derailleur” by Glory Cycles is licensed under CC BY 2.0.

“Pinarello Grevil” by Glory Cycles is licensed under CC BY 2.0.

If you want to fit an chainset with 11-speed cassette to your bike, the Di2 RD-RX815 (2×11) or Di2 RD-RX817 (1×11) derailleur is for you. With the 10-speed cassette, you only have the choice of one mechanical derailleur, the RD-RX400.

“Cervelo Aspero Shimano GRX Gravel Machine” by Glory Cycles is licensed under CC BY 2.0.

In the Shimano GRX group you will find both mechanical and electronic gearshift/brake levers:

• The first noticeable change to the GRX levers is the shape of the cover, which is higher than that of the road levers.
• The aim of this solution is to provide better grip and hand stability in varied and difficult terrain.
• The hand is supposed to be better able to hold the hoods and make it easier to operate the brake levers.
• The brake axle on the ST-RX815 levers is raised by 18mm for better brake leverage usability.
• The brake lever hoods and blades have a textured surface to prevent your hands from slipping.

Taking a closer look at the new gravel levers, Shimano has made a few changes to better protect the hands in the hoods and make the brakes easier to use. The ST-RX815 levers have the brake axle raised by 18mm, providing a slightly wider brake lever range. The lever blade itself is slightly curved for easy finger access, and the brake lever hoods and blades have a textured surface to prevent hand slippage.

If you’ve only ever ridden road grips before, you’ll notice the difference in grip immediately with the GRX lever. As a result, you will experience improved braking comfort when navigating difficult and demanding terrain.

In the case of the Shimano GRX Di2 levers, the change in grip is even more noticeable, as the electronic components take up less space than mechanical components and the manufacturers had more options for shaping the handles. The upper part of the hoods is curved back even further, making it even more pronounced for better grip on the handles in the field.

It may come as a surprise to many of you to learn that the two Shimano GRX left-hand grips, the ST-RX810-LA and ST-RX600-LA for 1×11 chainsets, have an additional usable function, which is to control the height of the seatpost/post dropper with a 9 mm lever travel.

Another solution that is new and different from road bikes is the BL-RX812 inline hydraulic sub-brake lever You mount them in the upper, central part of the handlebar. The technology consists in connecting these levers to the main hydraulic line running to the front and/or rear caliper.

If you find situations in your case where this solution will be needed, attractive and useful then it is worth considering this purchase. It is possible to use only the left or right lever – these are sold separately.

In the table below you will find the exact specifications of the individual Shimano GRX levers:

In the Shimano GRX group, disc brake calipers are available in two subgroups:

• BR-RX810
• BR-RX410

The GRX calipers are mounted with Flat Mount Technology and feature a low-profile design for greater control in varied terrain. The manufacturer has incorporated ICE TECHNOLOGIES and ONE WAY BLEEDING.

Brake levers and callipers can be purchased in sets or separately.

As you are probably already aware, the selection of individual components in the GRX group can be confusing. It is no different when it comes to the selection of brake levers and callipers. That’s why we’ve decided to prepare the table below to show you how you can match the different GRX brake calipers and lever models with each other.

Shimano also offers two ready-made gravel wheel sets, adapted to tubeless kits in either 700C or 650b size. Each wheel has an inner rim width of 21.6 mm and a rim height of 22 mm. The rims in the wheels are asymmetrical, which means they will be even more robust and stiff, and you can increase their potential during periodic servicing of the bicycle wheels, which you can have done in our manufactory.

The table below shows the technical specifications of Shimano gravel wheels.