Will a Shimano Micro Spline cassette fit an HG freehub?
By Crankworthy · Published · Updated
No. A Micro Spline cassette needs a Micro Spline freehub body. It uses finer splines and reaches down to a 10-tooth cog that an HG body physically cannot accommodate, so there is no adapter — you change the freehub body or choose a 12-speed cassette made for HG.
Why
Micro Spline is the freehub standard Shimano introduced for its 12-speed mountain groupsets — Deore M6100, SLX, XT and XTR. The splines are finer and more numerous than HG, which lets the cassette carry a 10-tooth smallest cog.
An HG body cannot go below 11 teeth: its minimum diameter is too large for a 10T cog to fit over it. That is a physical limit, not a compatibility setting, so no spacer or adapter can bridge the two.
Micro Spline driver bodies are only made for hubs whose manufacturer produces one, so a body swap is possible on some hubs and not on others. Check your hub model before buying a Micro Spline cassette.
How to tell which freehub you have
- HG
- Wider splines, and a cassette whose smallest cog has 11 teeth or more.
- Micro Spline
- Many fine splines, and a Shimano 12-speed cassette with a 10-tooth smallest cog. The hub body is often marked "Micro Spline".
12-speed cassettes that fit an HG freehub instead
These use an 11-tooth smallest cog so they mount on a standard HG body — no driver swap and no new wheel.
- SRAM PG-1210 NX Eagle (11-50T)12-speed 11-50T, fits standard HG freehub (no XD driver needed)$79.50Amazon
- SunRace CSMZ903 (11-51T)12-speed 11-51T, HG spline (no XD needed), Shimano/SRAM compatible
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