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Shimano GRX ST -RX810 STI Shifter & Disc Brake Caliper


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GRX ST-RX810 STI Shifter & Disc Brake Caliper

There are few drawbacks to gravel racing and adventuring, but we'd wager that the largest has been deciding between road and mountain components to build up our drop bar bikes for off-road rallying. With chain slap in the rear, and hoods that aren't built for rugged terrain in the front, things could get scary in the cockpit, but with Shimano's release of its gravel-specific GRX groupset, both of those issues are flown by the wayside. Shimano's GRX ST -RX810 STI Shifter & Disc Brake Caliper offer you shifters that are tuned specifically for gravel riding, with all-new hood designs that feature a more drastic slope to keep you secure when the going gets rough, and a redesigned pivot point on the lever to make pulling the brake all that much more confidence inspiring.

Shimano spent the last two years developing the new GRX group that's specifically designed to tackle dirt roads and singletrack on drop-bar machines, and they incorporated plenty of feedback from dedicated gravel racers and enthusiasts in the process. The RX810 mechanical shifters are largely similar in design to Shimano's current road shifters, offering the same light shifting action that rider's have come to know and love. The changes lie in a refined lever shape that improves comfort for mixed terrain riding, as well as a textured anti-slip surface on the levers that improves braking grip and control. The RX810 hydraulic calipers are effectively the same as Shimano's flat-mount road calipers, delivering powerful braking performance of ServoWave, with heat-dissipating Ice Tech brake pads, as well as simple set up and maintenance thanks to One-Way Bleeding technology.

  • Shimano's gravel-specific calipers and shifters for 2x drivetrains
  • Refined lever ergonomics improve comfort for off-road riding
  • Textured anti-slip lever surface improves braking grip and control
  • Powerful, consistent stopping power with Ice Tech brake pads
  • Simple setup and maintenance thanks to One-Way Bleeding technology
  • Includes one shifter and one pre-bled, flat-mount caliper
  • Item #SHIU19I

ST-RX810-R, ST-RX810-L
Lever Adjustability
[brake] hydrualic, [shifter] mechanical
Mount Type
mineral oil
not included
Claimed Weight
[left] (lever) 284g, (caliper) 148g, [right] (lever) 286g, (caliper) 138g
Manufacturer Warranty
2 years

Tech Specs

What do you think about this product?


>Rating: 4

A Big Step in the Right Direction

I've used it several times

Gravel has been the fastest growing segment for the past few years and Shimano has finally done something about it. GRX is a much needed drivetrain but doesn't quite go far enough with gearing for us casual riders in the mountains. To start with, performance and looks are on par with Shimano's road groups, so really good. It's a very clean looking groupset. So if you've liked your Ultegra drivetrain but want easier gearing, going to GRX makes good sense. There's some compatibility between the two groups too which is nice. The shifter bodies seem a bit larger for more grip but still work well for my small hands. They've got reach adjust (useful) and free stroke adjust which is not really useful - these brakes already seem to have a lot of throw and I had to do some fine bleed tuning to firm them up - bleeding these was a pain (but I've not bled other Shimano road brakes before). A very exciting step from Shimano is their decision to offer their 1x shifters with a left lever that activates a dropper! I plan to add one to my gravel bike eventually. One minor complaint I had that doesn't affect performance is that after folding the hoods back a few times for bleeds they tend to pucker away from the body on the sides. I've had a 105 shifter paired with an SLX rear derailleur and 11-42t rear cassette (using Wolf Tooth's excellent Tanpan adapter) on the bike until now so I already knew what to expect for gearing but GRX really does shift crisper without that adapter and this group feels lighter weight.


Hydraulic hoses are included ?? Ready for 160 or 140 rotors ??


Is the rear caliper set up to run a 140 mm rotor? Do you need an adapter to run a 160mm rotor (or is it supplied)?