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ShimanoXTR RD-M9120 Rear Derailleur


Item # SHI00LA

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  • Stealth Gray, SGS 12 Speed ($272.99)
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Item # SHI00LA

XTR RD-M9120 Rear Derailleur

Shimano may have taken its sweet time when jumping into the world of 12-speed, but patience is a virtue, and it seems like our wait was certainly rewarded, as its new XTR 12-speed groupset soars right back to the front of the cutting edge, while offering even better shifting performance than before. But just because Shimano soared into the future doesn't mean its designers didn't still keep an eye out for those who are still all-for the two-by persuasion, and the XTR RD-M9120 Rear Derailleur drives the point home. This two-by optimized rear derailleur is specifically designed to pair Shimano's 10-45-tooth 12-speed cassette with a double-ring crankset, offering more gears than most of us know what to do with, while keeping things quiet and smooth.

The M9120 Rear Derailleur sees improved chain stability and reduced friction thanks to larger 13t pulley wheels, making it better able to withstand full-force pedaling while shifting gears as smoothly as ever. Shimano was also able to decrease the rear derailleur tension in the lower gear positions, preventing the high chain tension that causes excess friction and noise, and thus a loss of efficiency. The Shadow RD+ clutch system provides excellent chain retention in rough terrain, and keeps annoying chain slap to a minimum. Lastly, the addition of a protective bumper to the inside of the derailleur cage quiets operation even further by cushioning the sound of any chain rub.

Because the RD-M9120 is optimized for a two-by system, it only comes in Shimano's SGS model. This means the derailleur has plenty of range to take on the new 10-45t Ryhtym-Step 12-speed cassette, and allows for some play in the front when you're swapping from the little ring to big ring.

  • A two-by-twelve ready derailleur for smooth and quiet shifting
  • Decreased chain tension in low gears elevates efficiency
  • Accommodates a two-by system for those who want endless gears
  • Larger 13t pulley wheels for better chain stability and shifting
  • Shadow RD+ clutch minimizes chain slap and prevents chain drop
  • Protective bumper in the cage quiets the sound of chain rub
  • Gradients on back of cage for easier limit screw setup

Tech Specs
Cage Length[sgs] long
Capacity2x 10-45t 12-speed cassette
Gearing2 x 12
Compatibility[chain] XTR CN-M9100, [cassette] XTR CS-M9100, [shifter] XTR SL-M9100-R, XTR SL-M9100-IR, [front derailleur] XTR FD-9100-M, XTR FD-9100-E, XTR FD-M9100-D
Recommended Usemountain
Manufacturer Warranty3 years

Actual Weight

Stealth Gray, SGS 12 Speed

Claimed Weight

Claimed weights are provided by the vendor.

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Actual weights are measured in-house by the Competitive Cyclist team.

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What do you think about this product?


>Rating: 5

Crisp and Light

I've put it through the wringer

Not much to say beyond that the XTR derailleur is precise, reliable and a tad lighter than the XT/SLX alternatives on the market. Although a bit pricey, I've had great luck pairing the XTR rear mech with XT cassettes. If you want a crisp setup for serious trail riding or racing, look no further!