Shimano GRX RD-RX812 Rear Derailleur

GRX RX812 derailleur delivers smooth, clutch-stabilized shifting for gravel adventures

What Our Gearhead® Experts Are Saying:

"I switched to the GRX RX812 for my 1x gravel rig and haven’t looked back. The clutch keeps my chain tight over chunky descents, and shifting stays smooth even when my drivetrain’s covered in dust and mud. It’s basically MTB toughness adapted perfectly for drop bars."

From washboard descents to rocky doubletrack climbs, we rely on the Shimano GRX RX812 Rear Derailleur to keep our shifting crisp and our chain quiet. Purpose-built for gravel and adventure riding, this derailleur brings proven Shimano MTB tech into the drop-bar world, so we can charge harder without worrying about dropped chains or ghost shifts.

The RX812 uses a clutch-based Shadow RD+ design to maintain consistent chain tension, especially when the terrain gets rough. It´s optimized for a 1x11 drivetrain with an 11–42t cassette range, giving us simplicity up front and plenty of gearing in the back. Whether we’re racing a gravel grinder or tackling a weeklong bikepacking route, this derailleur delivers smooth, reliable performance with zero drama.

Details

• Gravel-specific rear derailleur built for 1x11-speed drivetrains
• Ideal for mixed-terrain riding, gravel racing, and bikepacking
• Shadow RD+ clutch keeps chain tensioned over rough terrain
• Designed for wide-range 11–42t cassettes
• Smooth, reliable shifting with Shimano’s signature precision
• Low-profile design resists impact and stays quiet
• Compatible with Shimano road 11 speed shifters
• Alloy construction keeps weight low and durability high
• Item #SHIU19E

Tech Specs

Material

alloy

Capacity

31t

Cassette Range

[maximum] 11 - 42t, [minimum] 11 - 40t

Gearing

1 x 11

Compatibility

Shimano 11speed

Claimed Weight

9.4oz (267g)

Activity

gravel

Manufacturer Warranty

2 years