Shimano CS-M8100 Cassette
What the checker says129will not fit23check before you buy
Run variant by variant through the mountain bike builder’s own engine. Every sentence below is the checker’s, unedited. Nothing here says this part fits your bike; it says what it does and does not fit among the parts we hold.
Checked against 6114 verified mountain bike parts in this catalog. 5475 produced no finding of any kind; that is CS-M8100 10-45 (2019). CS-M8100 10-51 (2019) clears 5470. Each variant produces 77 to 106 distinct errors and 23 distinct warnings.
Will not fit
- Will not fiterror · Rear WheelFreehub mismatch: Shimano CS-M8100 10-45 needs a Shimano Micro Spline freehub, but Rear wheel has SRAM XD. On 239 of the 607 verified rear wheels in this catalog. Applies to 1 of 2 variants.
- Will not fiterror · Rear WheelFreehub mismatch: Shimano CS-M8100 10-51 needs a Shimano Micro Spline freehub, but Rear wheel has SRAM XD. On 239 of the 607 verified rear wheels in this catalog. Applies to 1 of 2 variants.
- Will not fiterror · Rear WheelFreehub mismatch: Shimano CS-M8100 10-45 needs a Shimano Micro Spline freehub, but Rear wheel has Shimano HG. On 136 of the 607 verified rear wheels in this catalog. Applies to 1 of 2 variants.
- Will not fiterror · Rear WheelFreehub mismatch: Shimano CS-M8100 10-51 needs a Shimano Micro Spline freehub, but Rear wheel has Shimano HG. On 136 of the 607 verified rear wheels in this catalog. Applies to 1 of 2 variants.
- Will not fiterror · Rear HubFreehub mismatch: Shimano CS-M8100 10-45 needs a Shimano Micro Spline freehub, but Rear wheel has Shimano HG. On 37 of the 124 verified rear hubs in this catalog. Applies to 1 of 2 variants.
- Will not fiterror · Rear HubFreehub mismatch: Shimano CS-M8100 10-51 needs a Shimano Micro Spline freehub, but Rear wheel has Shimano HG. On 37 of the 124 verified rear hubs in this catalog. Applies to 1 of 2 variants.
- Will not fiterror · Rear HubFreehub mismatch: Shimano CS-M8100 10-45 needs a Shimano Micro Spline freehub, but Rear wheel has SRAM XD. On 35 of the 124 verified rear hubs in this catalog. Applies to 1 of 2 variants.
- Will not fiterror · Rear HubFreehub mismatch: Shimano CS-M8100 10-51 needs a Shimano Micro Spline freehub, but Rear wheel has SRAM XD. On 35 of the 124 verified rear hubs in this catalog. Applies to 1 of 2 variants.
Cassette capacity, Rear Derailleur. 57 more findings from the same check, on up to 1 of the 75 verified rear derailleurs each.
Drivetrain system, Chain. 15 more findings from the same check, on up to 6 of the 45 verified chains each.
Drivetrain system, Rear Derailleur. 13 more findings from the same check, on up to 21 of the 75 verified rear derailleurs each.
Drivetrain system, Shifter. 12 more findings from the same check, on up to 11 of the 53 verified shifters each.
Drivetrain speeds, Rear Derailleur. 5 more findings from the same check, on up to 16 of the 75 verified rear derailleurs each.
Drivetrain speeds, Shifter. 5 more findings from the same check, on up to 10 of the 53 verified shifters each.
Drivetrain system, Front Derailleur. 4 more findings from the same check, on up to 12 of the 34 verified front derailleurs each.
Freehub, Rear Hub. 4 more findings from the same check, on up to 4 of the 124 verified rear hubs each.
Freehub, Rear Wheel. 4 more findings from the same check, on up to 19 of the 607 verified rear wheels each.
Gearbox cassette, Gearbox. 2 more findings from the same check, on up to 6 of the 6 verified gearboxs each.
Open a variant in the builder to see the ones that apply to your own parts.
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Front derailleur speeds, Front Derailleur. 23 more findings from the same check, on up to 1 of the 34 verified front derailleurs each.
Open a variant in the builder to see the ones that apply to your own parts.
$185.00 MSRP·461 to 470 g
What the maker states
- Speeds
- 12-speed (rear index count the maker rates it for)
- System
- Drivetrain system Shimano 12-speed
- Freehub
- / driver Shimano Micro Spline
- Minimum cog
- Smallest cog 10 teeth
- Maximum cog
- Largest cog 45 teeth (on 1 of 2 variants); Largest cog 51 teeth (on 1 of 2 variants)
A value shown as a set or a range differs between this model’s variants and is never one variant’s spec.
2 verified variants
| Variant | Maximum cog | Price (MSRP) | Weight | Source | Last checked | Build |
|---|---|---|---|---|---|---|
| CS-M8100 10-51 (2019) | Largest cog 51 teeth | $185.00 | 470 g | maker’s page | 2026-06-22 | Build with this |
| CS-M8100 10-45 (2019) | Largest cog 45 teeth | $185.00 | 461 g | maker’s page | 2026-08-15 | Build with this |
Source
Source: each variant links the maker’s own page in the table above. Last checked 2026-06-22 to 2026-08-15.
Checked against
The checker ran this model against every verified part below that it has a slot for, the same way it checks a build in the builder. What follows is the verdict it actually produced for that specific pairing — not a recommendation, and not a guarantee any of these parts fits your own bike.
- 5DEV R-SPEC Trail/Enduro Cranks (Crankset) No conflicts found
- 9point8 Fall Line (Dropper Post) No conflicts found
- 9point8 Stout (31.8, 30mm) (Stem) No conflicts found
- ACID SLX 30 front (Front Wheel) No conflicts found
- ACID SLX 30 rear (Rear Wheel) Will not fit
- Acros ZS44/ZS56 (Headset) No conflicts found
6 of 1875 counterparts with a page of their own that the checker actually probed this model against, in alphabetical order by brand and model — never by price, popularity or the verdict itself.