Short answer: a cassette fits only if it matches your freehub body type. There are five in common use — Shimano HG, Shimano 11-speed road HG, Shimano Micro Spline, SRAM XD, and SRAM XDR — plus Campagnolo's own. Speed count alone tells you nothing. A 12-speed SRAM Eagle cassette exists in two versions that need different freehubs.
Contents
- The compatibility table
- How to identify your freehub body
- Shimano HG: 7 to 11 speed
- The 11-speed road body, and why it's different
- Shimano Micro Spline
- SRAM XD and XDR
- Campagnolo
- The SRAM Eagle trap
- Spacers: when you need one
- Can you change your freehub body?
- Common mistakes
- FAQ
The compatibility table
Find your freehub body in the left column. Everything in that row will fit.
| Freehub body | Cassettes that fit | Smallest cog possible | Notes |
|---|---|---|---|
| Shimano HG (standard) | 7, 8, 9, 10-speed road and MTB; 11-speed MTB; SRAM 7–11 speed; SRAM NX Eagle 12-speed | 11T | The most common body ever made. Spacer needed for 7-speed. |
| Shimano HG 11-speed road | 11-speed road; 12-speed Shimano road; 10-speed with spacer | 11T | 1.85mm wider than standard HG. |
| Shimano Micro Spline | Shimano 12-speed MTB only | 10T | Not compatible with anything HG. |
| SRAM XD | SRAM XD cassettes (Eagle XG series, MTB 11/12-speed) | 10T | Threaded interface, not splined like HG. |
| SRAM XDR | SRAM XDR road cassettes; XD cassettes with a 1.85mm spacer | 10T | 1.85mm wider than XD. |
| Campagnolo | Campagnolo 9–12 speed | 11T | Own spline pattern. Not cross-compatible. |
| Campagnolo N3W | Campagnolo 13-speed and Ekar; older Campag via adapter | 9T | Newer standard. |
How to identify your freehub body
Take the cassette off and look at the splines. You can tell all five apart by eye in a few seconds.
| What you see | Body type |
|---|---|
| Nine splines running the length of the body, one noticeably wider than the rest | Shimano HG (standard or 11-speed road) |
| Same nine splines but the body is visibly longer | Shimano HG 11-speed road |
| Many fine, shallow splines — around 23 of them | Shimano Micro Spline |
| Smooth, stepped profile with a threaded section at the outer end | SRAM XD or XDR |
| Deep, evenly spaced splines with no wide one | Campagnolo |
To separate XD from XDR: measure the body length. XDR is 1.85mm longer. If you can't measure it, check what bike it came off — XDR is road, XD is mountain.
To separate standard HG from 11-speed road HG without a cassette to hand: if the wheel came on an 11-speed road bike, it's the road body. If it came on anything 10-speed or older, or on a mountain bike, it's standard.
Shimano HG: 7 to 11 speed
Hyperglide has been the industry default since the late 1980s and covers most bikes on Indian roads today.
A standard HG body takes 8, 9 and 10-speed cassettes in both road and MTB, and 11-speed MTB, with no modification. The cassettes are all the same width; only the sprocket spacing changes.
Seven-speed is the exception. Those cassettes are narrower, so they need a spacer behind them to sit correctly.
In-stock HG cassettes: SRAM PG1030 10-speed, PG 950 9-speed, PG1130 11-speed, Shimano Claris 8-speed, GRX 10-speed.
The 11-speed road body, and why it's different
When Shimano moved road groupsets to 11 speeds, the cassette needed more width than the existing HG body allowed. So the body got 1.85mm longer.
Two consequences follow, and they trip people up constantly.
An 11-speed road cassette will not fit a standard HG body. There is no spacer that fixes this. The body is physically too short. You need a different freehub body or a different wheel.
A 10-speed cassette will fit an 11-speed road body, but only with a 1.85mm spacer behind it. Without the spacer the cassette sits too far inboard, the lockring won't tighten properly, and your shifting will never index correctly.
The useful piece of news: Shimano's 12-speed road cassettes use the same 11-speed road body. If you're on an 11-speed road wheel and moving to 12-speed Shimano, the wheel carries over. That's unusual generosity in a component industry and worth knowing before you shop for new wheels.
In stock: Shimano Ultegra CS-R8000 11-speed and Ultegra CS-HG800 11-34T.
Shimano Micro Spline
Micro Spline exists for one reason: to allow a 10-tooth smallest sprocket. An HG body is too wide at the base for a 10T cog to clear, so Shimano designed a narrower interface with around 23 fine splines.
It is used on Shimano 12-speed mountain groupsets and is not compatible with HG in either direction. If you want Shimano 12-speed MTB, you need a Micro Spline freehub body, and on many wheels that means buying one from the hub manufacturer.
SRAM XD and XDR
SRAM solved the same 10-tooth problem differently. Instead of splines carrying the drive load, an XD cassette threads onto the body and the cassette itself forms the structure.
There are two versions and the difference is only width:
| XD | XDR | |
|---|---|---|
| Intended use | Mountain | Road and gravel |
| Body width | Narrower | 1.85mm wider |
| Takes XD cassettes | Yes | Yes, with 1.85mm spacer |
| Takes XDR cassettes | No | Yes |
The rule that follows: XD cassettes fit XDR bodies with a spacer. XDR cassettes never fit XD bodies.
SRAM's 12-speed road groupsets — Red, Force, Rival and Apex AXS — use XDR. In stock: SRAM Rival XG-1250, XPLR XG-1251, Force XG-1270.
Campagnolo
Campagnolo uses its own spline pattern and always has. Nothing from Shimano or SRAM fits a Campagnolo body, and nothing Campagnolo fits theirs.
Their newer N3W standard supports smaller sprockets for gravel use and accepts older Campagnolo cassettes through an adapter. If you're running Campagnolo, buy Campagnolo, and check whether your hub is the older type or N3W before ordering.
The SRAM Eagle trap
This one catches experienced mechanics, so it deserves its own section.
SRAM sells 12-speed Eagle cassettes for two different freehub bodies, and the product names don't make it obvious:
| Cassette | Freehub needed | Smallest cog |
|---|---|---|
| XG-1275, XG-1295, XG-1299 (GX, X01, XX1 Eagle) | XD | 10T |
| PG-1210, PG-1230 (SX and NX Eagle) | Standard HG | 11T |
Both are "SRAM Eagle 12-speed." One needs an XD driver, one runs on the HG body your bike probably already has. If you order the wrong one it simply will not go on.
We stock both: XG-1275 (XD) and PG1230 (HG).
Spacers: when you need one
| Situation | Spacer |
|---|---|
| 7-speed cassette on a standard HG body | 4.5mm |
| 10-speed road cassette on an 11-speed road body | 1.85mm |
| XD cassette on an XDR body | 1.85mm |
| 8, 9, 10, 11-speed on the body they were designed for | None |
Spacers usually ship with the cassette or the wheel. If your new cassette sits proud of the body and the lockring won't bite, you're missing one. If it sits too deep and the lockring bottoms out before clamping, you have one too many.
Can you change your freehub body?
On most quality wheels, yes. The freehub body is a serviceable part that pulls off the hub shell, usually held by the end cap and the axle. Swapping HG for XDR, or HG for Micro Spline, is a common upgrade path.
What you need to check first:
- Does your hub manufacturer make the body you want? DT Swiss, Fulcrum, Campagnolo, Hunt, Zipp and most premium brands offer multiple options. Budget and OEM wheels often don't.
- Which hub model exactly? Freehub bodies are model-specific, not brand-specific. A DT Swiss 350 body doesn't fit a DT Swiss 240.
- Is the wheel worth it? A replacement body can cost a meaningful fraction of a budget wheelset. On cheaper wheels, a new wheel is sometimes the better spend.
If you're unsure what your hub is, send us a photo of the hub body with the cassette off and we'll identify it.
Common mistakes
Assuming speed count determines fit. It doesn't. An 11-speed MTB cassette and an 11-speed road cassette need different bodies. Two 12-speed Eagle cassettes need different bodies.
Forcing a cassette that doesn't seat. If it won't slide on fully, it's the wrong type. Nothing about a correctly matched cassette requires force.
Buying a wheelset without checking the driver. Wheel listings often state the freehub as an afterthought, and many wheels ship with HG as standard. If you run SRAM AXS, you need to confirm XDR before ordering.
Reusing the old lockring on a different cassette type. XD and XDR cassettes use their own lockring, integrated differently to HG.
Ignoring derailleur capacity. A cassette can fit the freehub perfectly and still be unusable if your rear derailleur can't handle the largest sprocket. Check the maximum cog size for your derailleur separately.
FAQ
Will an 11-speed cassette fit a 10-speed freehub?
An 11-speed road cassette will not fit a 10-speed HG body — the body is 1.85mm too short and no spacer solves it. An 11-speed MTB cassette will fit, because Shimano designed those to work on the standard HG body.
Will a 10-speed cassette fit an 11-speed freehub?
Yes, with a 1.85mm spacer fitted behind the cassette. Without it the cassette sits too far in and shifting cannot be indexed correctly.
Do Shimano 12-speed road cassettes need a new wheel?
No. Shimano 12-speed road uses the same freehub body as 11-speed road. If your current wheel takes an 11-speed road cassette, it takes a 12-speed one.
What is the difference between XD and XDR?
Width only. XDR is 1.85mm wider and is the road version. An XD cassette will fit an XDR body with a spacer; an XDR cassette will not fit an XD body at all.
Can I fit a SRAM cassette on a Shimano freehub?
For 7 to 11-speed, yes — SRAM makes those to the HG standard and they are interchangeable with Shimano. For 12-speed it depends: SRAM's NX and SX Eagle cassettes fit an HG body, but GX, X01 and XX1 Eagle need an XD driver, and all SRAM 12-speed road cassettes need XDR.
How do I know if my wheel has an XD or XDR driver?
Remove the cassette and look for a threaded section at the outer end of the body — that identifies it as XD family. To tell the two apart, measure the body length; XDR is 1.85mm longer. In practice, a road or gravel wheel bought for SRAM AXS will be XDR, and a mountain wheel will be XD.
Does Campagnolo work with anything else?
No. Campagnolo's spline pattern is unique and cassettes are not cross-compatible with Shimano or SRAM in either direction.
My new cassette wobbles slightly. Is that normal?
A very small amount of play between individual sprockets and the body is normal on HG cassettes, particularly loose-sprocket ones. What is not normal is the whole cassette rocking, which usually means a missing spacer or an under-tightened lockring.
Last updated: August 2026.
Not sure what you have? Send a photo of your hub with the cassette removed to our WhatsApp and we'll tell you which cassettes fit. Browse in-stock cassettes here.
Related: Monsoon bike maintenance · Basic bicycle maintenance