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Shimano GRX RD-RX817 11-Speed Di2 Rear Derailleur
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Shimano GRX RD-RX817 11-Speed Di2 Rear Derailleur


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Mfg PartNum: IRDRX817
SALE: $217.74
MSRP: $334.99
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GRX RD-RX817 11-Speed Di2 Rear Derailleur

With an integrated chain stabilizer mechanism, the Shimano GRX RD-RX817 11-Speed Di2 Rear Derailleur provides a quieter experience and shifting security and precision on mixed terrain.

For rides on smooth surfaces, the derailleur features and ON/OFF switch for the chain tensioner. The RD-RX817 DI2 version offers the digital precision of SHIMANO electronic shifting and synchronized shifting. and is compatible with mtb cassettes with a 42T low sprocket max.


  • Silent and uninterrupted rear shifting on rough terrain
  • Operates with Shimano Di2 for digital electronic shifting
  • Adjustable chain stabilizer prevents chain slapping and drops
  • Smooth and reliable mixed surface shifting
  • Switch stabilizer ON/OFF to match the terrain
  • Gravel-tuned clutch tension
  • Compatible with current road DUAL CONTROL LEVER

  • B-Stock - This product has one or more B-Stock units available. These units can be purchased at a discount (see option select). B-Stock units were returned from other customers and may have missing or damaged packaging materials. These units are otherwise as new. The full manufacturer warranty applies. Click Here for more information.

    The product weight specified is an approximate weight based on the manufacturer's specifications (if available) or our measurement of one or two examples. For most products, the weight will typically vary by 5% to 10%.


    Model Number: RD-RX817 

    Series: SHIMANO GRX DI2 

    Weight: 318 g

    Direct Attachment: Yes 

    E-tube connector (pcs): 

    E-tube port (pcs): 

    Firmware update by E-TUBE Project: Yes 

    Fluoric coated link bushings: 

    Low sprocket: 42T (max) / 40T (min) 

    Sealed bearing guide pulley: Yes 

    Sealed bearing tension pulley: Yes 

    Top-Normal Spring Type: SHADOW RD plus 

    Top sprocket: 11T (Max/Min) 

    Total Capacity: 31T 

    Actuation: Electronic 

    Discipline: Road/Gravel 

    Mount Type: Standard Rear Hanger 

    Speed: 11 


    Ordered by Most Relevant First
    5 stars
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    1 stars
    Reviewed 10/12/2020
    Cycling Enthusiast
    Seattle area
    Value Rating
    Overall Rating
    1 of 1 customers found this review helpful.
    It does what Shimano says, AND MORE!

    I installed this on my Co-Motion Tandem, running DI2 Ultegra 8070 group. First, being a tandem, a wide gear range is needed. Second, road DI2 only runs 2X drivetrains. Third, I use a FSA Gossamer triple crankset, using only the middle and big rings as a double. This means the smallest available chainring is a 39T ring. I run an 11-40 SRAM cassette. The GRX RD-RX817 11-Speed Di2 Rear Derailleur is spec'd to run an 11-40 or 11-42 cassette, but for a 1X drivetrain. Well, the drivetrain shifts super smooth now! It works flawlessly with the 2X drivetrain, including the auto shift functions. It's well worth the money.

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