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Shimano GRX RD-RX812 11-Speed Rear Derailleur
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Shimano GRX RD-RX812 11-Speed Rear Derailleur

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Mfg PartNum: IRDRX812
MSRP: $119.99
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Shimano GRX Rear Derailleur — RD-RX812

With an integrated chain stabilizer mechanism, the SHIMANO GRX derailleur provides a quieter experience and shifting security and precision on mixed terrain. For rides on smooth surfaces, the derailleur features an ON/OFF switch for the chain tensioner. The RD-RX812 rear derailleur is compatible with MTB cassettes with a 42T low sprocket max.


  • For 1x drivetrains
  • Adjustable chain stabilizer prevents chain slapping and drops
  • Switch stabilizer ON/OFF to match the terrain
  • Gravel-tuned clutch tension
  • Silent and uninterrupted rear shifting on rough terrain
  • Smooth and reliable mixed surface shifting
  • Compatible with current road DUAL CONTROL LEVER
  • Top sprocket: Max. 11T/Min. 11T
  • Low sprocket: Max. 42T/Min. 40T
  • Total capacity: 31T

  • 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%.


    Mfg PartNum: IRDRX812 

    Mfg PartNum: IRDRX812 

    Mfg PartNum: RD-RX812 

    Series: SHIMANO GRX 11-speed 

    Weight: 267 g

    Compatible chain: HG-EV 11-speed/HG-X11 

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

    Rear Speeds: 11 

    Top-Normal Spring Type: SHIMANO SHADOW RD  

    Top sprocket: 11T (Max/Min) 

    Total Capacity: 31T 

    Actuation: Mechanical 

    Discipline: Road/Gravel 

    Mount Type: Standard Rear Hanger 

    Speed: 11 

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