Finally on the shelves of bike shops is the long-awaited Shimano GRX groupset aimed at gravel and adventure bikes. Offering 10 and 11 speed drivetrains and in 1x and 2x configurations, Shimano GRX has something for everyone at a few different price points too. We are testing a (mostly) GRX RX600 mechanical groupset with hydraulic brakes, here are all the details, plus weights, prices and lots of photos. 

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If you want to read all about the different new groupset and all the electronic and mechanical configurations, road.cc has a great article here. We'll just be discussing the groupset we have in for test, mostly made from GRX RX600 components which is slightly less expensive and a little heavier than the RX800 gear and sits at a "105" level. RX800 is Ultegra level kit with Di2 integration and the cheapest RX400 features Tiagra level components. 
 

Crankset and Chainring 

Our 1x crankset comes with a 40T chainring option, which is actually the only one available for the RX600 range, you can get 42T chainring if you choose RX810 or alternatively replace it with this chainring later if you want more teeth. Shimano uses the same crank arm for either 1x or 2x configurations so they can be converted to the other option in the future as well if you want/need. The single chainrings get Shimano's Dynamic Chain Engagement tooth profile to help stop you losing the chain over rough ground too. We weighed our crankset (175mm) with a 40T chainring at 747g. The crankset has a +2.5mm chainline for increased tyre and frame clearance, one they say is also better optimised for the wider gear spacing. 

• £119.99
• 747g

Cassette

The GRX groupset uses cassettes currently in production from the road and mountain bike lines. Shimano recommends Ultegra R8000 11spd, 105 R7000 11spd, HG800 11-34t 11spd, GH700 11-34t 11spd or from the MTB range XT or SLX 11 speed. We've got an XT cassette here (11-40T) which weighs 418g. We'll be using an 11spd chain too, weighing 232g.

• £79.99
• 418g

Rear Derailleur

There are four rear mechs, two for Di2 and two for mechanical duties, on offer with both short and long cage options, we've got the latter in for test (RX812), weighing in at 202g. There's a clutch as per the MTB gear and our is good for cassette sprockets up to 40t.

• £99.99
• 202g

STI shifter/brake levers

There are dedicated GRX levers which use a “gravel-specific ergonomic” lever design. Shimano says the hood is 18mm taller to provide a more secure hand position with a bigger 'scoop' in the centre of the brake lever alongside anti-slip texturing to prevent the hands/fingers sliding off the controls. Both of our hydraulic levers together weighed 599, with just the gear cable (no outer) attached. We have a specific lever, with no shifter internals ready to use with 1x set ups. If your gravel riding is getting rowdy and you want/need a dropper post, Shimano has developed a dedicated left-hand shifter that is compatible with cable-operated dropper posts with a 9mm lever throw.

• Left hand - £54.99
• Right hand - £169.99
• 599g
   

Brake calipers and discs

road.cc tell us that the flat mount brake calipers use the same design as the current road calipers but are stickered with GRX logos. We weighed ours with cable attached at 163g each. We will be using them with XT IceTech 160mm discs from the mountain bike range.

• £49.99 per caliper
• Discs - £31.99
• 163g each 
   

Wheels

Available in both 700c and 650B the Shimano GRX wheels are a neat looking, black alloy wheel with understated graphics. We will be testing the 650b wheels (1,640g), fitted to a 51/52cm sized bike for Rachael. Both have a 21.6mm internal width, a 22mm deep rim and 12mm thru axle. 

• Front - £189.99
• Rear - £209.99

We can't find a price for a full groupset, in fact, we can't find one for sale anywhere but adding it all up shows that bought separately, a Shimano GRX 1x11 groupset as we have here will cost £724 at full retail, not including wheels.  For those of you who are interested this little lot, also not including wheels weighs 2,765g with the only obvious omission being the bottom bracket, we are just waiting on the conformation of frame delivery before ordering the correct one.

• www.bike.shimano.com

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