For the last few years, gravel bike riding has been the big, new market in cycling. GRX is Shimano’s entry into the off road / gravel riding world. So, with rival manufacturer, SRAM, enjoying a near four year head-start with their gravel groupsets, will GRX be tempting enough to lure SRAM converts back?
What is GRX?
GRX is effectively three layers of goupsets from the top spec RX810 (ultegra level), RX600 (105 level) RX400 (Tiagra level). The RX600 & RX400 will appear on OEM equipment on gravel bikes. The RX800 series is available in either mechanical or electronic versions.
The GRX chainsets come in three options 1 x 11, 2 x 11 and 2 x 10. The chainline on all three chainsets has been moved outward slightly (2.5mm) to help accomodate wider tyres. The GRX 810 1 x 11 option comes in 40 or 42 tooth options, the 2 x 11 comes with 48/31 chainrings. The GRX 600 is available 1 x 11 40 tooth or 2 x 11 46/30.
Rear & Front Derailleurs
If you are using the 2 x 11 or 2 x 10 chainset options you would need the GRX front derailleur – the derailleur is designed to accomodate the wider chainline. The front derailleur features integrated tension adjustment and the same lighter touch front shifting as Shimano road groupsets.
The GRX 810 rear derailleur is the short cage option (up to 34T rear sprocket). The GRX 812 is the long cage option (up to 40T rear sprocket). There is also an electronic version available. All the GRX rear derailleurs use Shadow RD+ technology which stabilizes the derailleur and chain when the going gets choppy, reducing derailleur arm movement. The GRX rear derailleurs fit neatly under the cassette in a less exposed position to avoid contact on the trails.
Shifters & Brakes
Shimano GRX levers come in either electronic or mechanical variants. All the GRX levers feature ‘Gravel Specific Ergonomic’ lever design. Redesigned hoods and a higher braking pivot make braking whilst holding the hoods much easier and more comfortable.
The flat mount GRX 810 calipers are the identical to the current Ultegra road disc calipers, with a GRX logo.
The (BL-RX812 levers) inline hydraulic brake levers (like CX mini levers) allow riders to brake whilst hands are on the tops of the bars.
The RX570 wheels are also part the the GRX component range. Available in both 700c and 650b, the wheels feature 21.6mm internal width and are secured with 12mm through axles. Wheel weight is around 1600g / 1650g depending on the size.
See our GRX components and bike build options here.
Have been running GRX800 Di2 and can’t fault it. Its all the good bits of Ultegra with even better STI’s – the shape, feel and location of Di2 buttons all better IMHO. Never remember to switch the clutch ‘on’ though when I go off-roadin’ so the SRAM’s automatic damper wins there, but Shimano’s is good at reducing chain slap when it is on. I’m running 2 x with a 48/31 and a 11-32 at the rear and its ample for my mostly road and bridlepath exploits… but will switch to 11-34 if I ever get all beardy and fancy bike packing.