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Shimano GRX RD-RX400 10-Speed Rear Derailleur Shimano GRX RD-RX400 10-Speed Rear Derailleur
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Shimano GRX RD-RX400 10-Speed Rear Derailleur

Mfg PartNum:IRDRX400
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The Shimano GRX RD-RX400 10-speed rear derailleur keeps shifting silent and uninterrupted when riding on rough terrain.

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 and ON/OFF switch for the chain tensioner.

  • Smooth and reliable mixed surface shifting
  • Silent and uninterrupted rear shifting on rough terrain
  • Shadow RD+ chain stabilizer prevents chain slapping and drops
  • The gravel-tuned clutch tension helps to provide smooth and reliable mixed surface shifting
  • Stabilizer can be turned on/off to match terrain
  • Compatible with Shimano 10-speed road Dual Control Levers
  • Compatible with current 10s road Dual Control Lever
  • Wide range front gearing — Maximum front T difference: 16T
  • Top sprocket: Max. 11T/Min. 11T
  • Low sprocket: Max. 36T/Min. 32T
  • Total capacity: 41T

  • 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.

    Mfg PartNum: IRDRX400 

    Ordered by Most Relevant First
    5 stars
    4 stars
    3 stars
    2 stars
    1 stars
    Reviewed 4/28/2022
    by Anonymous
    Cycling Enthusiast
    Value Rating
    Overall Rating
    Great derailleur, but mine arrived with missing parts

    The derailleur itself is great. My Tiagra derailleur was worn out, so I replaced it with this one. The shifting has improved, and the clutch makes the bike much quieter over rough roads.

    However, some small parts were missing. There were supposed to be a small piece of cable and, more importantly, a special washer needed for installation. Luckily, the guy at the lbs who installed the derailleur found a used one. I did not bother to contact biketiresdirect because this was the last derailleur they had. Just be aware that not everything they sell is new and complete.

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    Reviewed 3/17/2022
    by Glyndwr
    Cycling Enthusiast
    Philadelphia, PA
    Value Rating
    Overall Rating
    Compatibility issues, despite advertisement

    The derailleur seemed to be a well-manufactured product , and I can't say it doesn't function properly with the correct shifters (perhaps MTB-style trigger or grip shifters?). However, everything I read from users and from the Shimano website suggested this could be used with road shifters, like 105, Ultegra or Dura-Ace. Unfortunately the cable pull of the shifter didn't match up correctly with that needed for the derailleur to travel properly from cog to cog, and the shifts were sloppy.

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    Reviewed 6/19/2020
    by Anonymous
    Overall Rating
    4 of 5 customers found this review helpful.
    Not compatible with older 10sp shifters

    This is a great med long cage derailer. Shimano says max 36 tooth, but it seems to be working fine on a 2x system with 42 max cog. Thing to note this is shimano's new shift ratio, so grx shifters or new tiagra shifters are required, older 10speed shifters do not work.

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    Reviewed 8/19/2020
    by Anonymous
    Cycling Enthusiast
    Pasadena, CA
    Overall Rating
    Major upgrade from Tiagra RD for gravel use

    Never quite felt like the Tiagra RD was suitable for rough gravel use (fallen chain, choppy shifting on climbs and descents). Very pleased that Shimano didn't overlook 10-speed bikes when they released their GRX components. The clutch system on the GRX RD is really amazing at reducing the chain slap (though at the expense of slightly less crisp shifting... but can always turn off the clutch for riding on smooth roads). On top of that I was able to put on a larger cassette to make climbing on gravel easier. The recommended max 11-36 cassette combined with my bike's 32/48 crankset gives me pretty much the exact range I need.

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