Shimano's entirely new Deore 12s M6100 group features many of the same technologies and component standards as XTR, XT and SLX. It's a dedicated 1x12 groupset with a 10-51t cassette, but requires Shimano's Micro Spline freehub body making upgrading an existing drivetrain difficult.
This is where Shimano's Deore 11s M5100 comes in. It also offers many of the same technologies including a 11-51T cassette, but utilizes the longstanding Shimano HG freehub standard making it the perfect option for upgrading existing 8/9/10 speed drivetrains.
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Components included in groupset:
Rear Derailleur: RD-M5100-SGS 11-Speed
Shifter: SL-M5100, Right, 1x11-Speed, Clamp Band, with or without gear display
Some variants may not appear in drop-down (if they're out of stock)
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Our thoughts:
This is by far the best and easiest upgrade option if you're looking to take advantage of the new wide gear ranges while retaining your existing HG hub/wheel which also delivers incredible value.