Shimano GRX Di2 RD-RX817 11-Speed Rear Derailleur — 42T Max, Medium Cage
IRDRX817
SKU code: SHM-IRDRX817
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Precise, reliable electronic shifting for gravel riding — the Shimano GRX Di2 RD-RX817 brings Di2 intelligence to 1x gravel drivetrains, handling anything from 11 to 42T with a terrain-tuned SHADOW RD+ clutch that keeps your chain secure on rough roads, fire trails, and everything in between.
Highlights
- Electronic Di2 shifting — instant, consistent gear changes at the touch of a button
- SHADOW RD+ integrated chain stabiliser prevents chain slap and dropped chains on rough terrain
- ON/OFF clutch switch — disengage chain stabiliser on smooth surfaces when not needed
- Designed specifically for 1x gravel drivetrains
- Supports Shimano Synchro Shift and Semi-automatic shift modes via E-TUBE Project
- Sealed bearing guide pulley and tension pulley for reduced friction and long service life
- 4 fluoric-coated link bushings for smooth, low-maintenance operation
- Firmware updatable via Shimano E-TUBE Project app
SHADOW RD+ Chain Control
The integrated chain stabiliser uses a friction-based clutch mechanism to maintain tension on the chain even over the most demanding surfaces. Unlike mechanical derailleurs that require a separate clutch adjustment, the RD-RX817's SHADOW RD+ engages quietly and consistently, reducing chain noise and eliminating dropped chains — so you can focus on the trail ahead. The on-the-fly ON/OFF switch means you can relax chain tension when riding paved roads to reduce drivetrain wear.
Di2 Electronic Precision
Shimano Di2 (Digital Integrated Intelligence) delivers shift actuation through electronic motors rather than cables, resulting in perfectly repeatable, weather-resistant shifting regardless of cable stretch or housing wear. The RD-RX817 features a single SD50 E-tube port and is compatible with Shimano's E-TUBE Project software, enabling firmware updates, custom shift modes, and multi-shift configuration.
Compatibility & Fit
The RD-RX817 is designed for 1x11-speed gravel drivetrains. It accepts cassettes with a low sprocket of 40–42T and a top sprocket of 11T, giving a total capacity of 31T. It is compatible with Shimano GRX Di2 shifters and the standard rear derailleur hanger mount. Not recommended for use with a front derailleur (1x only). Firmware must be up to date for full system compatibility — use Shimano E-TUBE Project to verify.
Shimano bicycle components are warranted to the original retail purchaser against defects in materials and workmanship for 2 years from the date of original purchase. This warranty does not cover normal wear and tear, damage from improper installation, misuse, or failure to perform regular maintenance. For warranty support, return the item to Tune Cycles.
- Shimano GRX Di2 electronic 11-speed rear derailleur
- SHADOW RD+ clutch with ON/OFF chain stabiliser switch
- Cassette compatibility: 11T top sprocket, 40–42T low sprocket
- Total capacity: 31T
- Weight: 318g
- Medium cage design
- 1x drivetrain specific
- 1 × SD50 E-tube port
- Sealed bearing guide and tension pulleys (11T)
- 4 fluoric-coated link bushings
- Synchro Shift and Semi-auto shift mode support
- Firmware updatable via E-TUBE Project
- Standard rear derailleur hanger mount
| Specification | Detail |
|---|---|
| Speed | 11-speed |
| Weight | 318g |
| Cage Length | Medium |
| Top Sprocket (max/min) | 11T |
| Low Sprocket (max) | 42T |
| Low Sprocket (min) | 40T |
| Total Capacity | 31T |
| Actuation | Electronic (Di2) |
| E-tube Ports | 1 × SD50 |
| Clutch / Chain Stabiliser | SHADOW RD+ (ON/OFF) |
| Pulley Teeth | 11T (guide & tension) |
| Mount Type | Standard rear hanger |
| Drivetrain Configuration | 1x only |
| Colour | Grey |
| Part Number | IRDRX817 |
| SKU | SHM-IRDRX817 |
| Barcode # | 4550170443177 |
| Brand | Shimano |
| Shipping Weight | 0.3000kg |
| Shipping Cubic | 0.001000000m3 |
| Unit Of Measure | each |
Must be installed and serviced by qualified bicycle mechanic
