Which freehub body fits my wheel? A simple guide for road bikes, MTBs & gravel bikes

If you want to upgrade your wheel, change the cassette or switch to a new groupset, the question quickly arises: Which freehub body actually fits my wheel?

Road, gravel and MTB bikes in particular now have several different freehub standards - and unfortunately, they are not all compatible with one another.

In this guide, we take a practical look at:

• which types of freehub bodies there are,
• how to identify what is installed on your wheel,
• what fits Shimano, SRAM, Campagnolo & Co.,
• and what you need to look out for when buying new wheels or hubs.

What exactly is a freehub - and why is it important?

The freehub body sits on the rear hub and is the part onto which you fit your cassette. It performs two tasks:

1. Power transmission: When you pedal, pawls or a ratchet system engage and drive the wheel.
2. Freehub: When you stop pedaling, the wheel can continue rotating while the crank remains still - hence the familiar clicking sound.

For your cassette to fit, these three things must match:

• Freehub standard (e.g. Shimano HG, Micro Spline, SRAM XD, XDR or Campagnolo)
• Number of sprockets (8-/9-/10-/11-/12-speed)
• Intended use (road bike, MTB, gravel or e-bike)

That’s why the question “Which freehub body fits my wheel?” is so important before you order anything.

The most important freehub standards at a glance

Shimano HG - the classic

Use:

• older and many current road bikes up to 11-speed
• very many 8- to 11-speed MTBs
• many trekking and city bikes

Features:

• slightly conical shape with longitudinal splines
• 8- to 11-speed cassettes fit depending on the version
• many Shimano and SRAM cassettes are suitable for this

Typically suitable for:

• Shimano 8-/9-/10-/11-speed cassettes
• many SRAM 8-/9-/10-speed cassettes

If you’re looking for a new cassette for your HG freehub body, you’ll find suitable models in our Cassettes & Sprockets category.

Shimano Micro Spline - modern MTB standard

Use:

• modern MTBs with Shimano 12-speed
• for example Deore, SLX, XT or XTR 12-speed

Features:

• many small, fine splines
• designed for 10-tooth smallest sprockets
• not compatible with classic HG cassettes

Typically suitable for:

• Shimano 12-speed MTB cassettes with a 10-tooth sprocket, for example 10–51

So if you ride a modern 12-speed Shimano MTB, there’s a good chance you have a Micro Spline freehub body.

SRAM XD and XDR - for modern SRAM drivetrains

SRAM XD (MTB)

• for 12-speed MTB cassettes with a 10-tooth sprocket, such as SRAM Eagle
• narrow, specialized freehub body

SRAM XDR (Road / Gravel)

• for modern SRAM 12-speed road and gravel cassettes
• similar to XD, but slightly longer

Important:

• XD and XDR are not compatible with Shimano HG or Micro Spline
• many modern gravel and road wheelsets are available in versions with XDR

Campagnolo freehub

Use:

• Road bikes with Campagnolo groupsets

Features:

• unique spline geometry
• Campagnolo cassettes require Campagnolo-specific freehubs

If you ride a classic Campagnolo road bike, it will generally have a suitable Campagnolo freehub installed.

How do I find out which freehub I have?

Before buying anything, you should check which system is installed on your wheelset.

Step 1 - Check what is currently installed on your wheelset

1. Turn the bicycle upside down or place it in a repair stand
2. Remove the rear wheel
3. Take a closer look at the cassette and hub

Ask yourself these questions:

• Which groupset do you use - Shimano, SRAM, or Campagnolo?
• How many sprockets does your cassette have?
• Do you ride a road bike, gravel bike, MTB, city bike, or e-bike?

This information alone often provides initial clues about the freehub standard installed.

Step 2 - Remove the cassette and inspect the freehub body

To be completely sure, it's best to briefly remove the cassette. You will usually need:

• cassette removal tool
• chain whip
• a wrench if necessary

Once the cassette is removed, you can see the bare freehub body:

• coarse longitudinal splines = usually Shimano HG
• many small, fine splines = usually Micro Spline
• narrow, specialized shape = possibly XD or XDR
• significantly different spline geometry = probably Campagnolo

If in doubt, simply take a photo of the freehub and cassette, compare it with product images, or ask us.

Step 3 - Check markings and manufacturer information

Many hubs or wheelsets have labels such as:

• Shimano HG
• Micro Spline
• XD or XDR
• Campagnolo

It's also worth checking:

• on the wheel manufacturer's website
• in the instruction manual
• in the product description in the shop

If you bought your wheelset or hub from us, you can find a lot of information directly in the product description. You can find an overview here:

• Wheelsets
• Hubs & Accessories

Which freehub fits which cassette?

Shimano HG

Compatible with:

• Shimano 8-/9-/10-/11-speed road and MTB cassettes
• many SRAM 8-/9-/10-speed cassettes
• some 11-speed road cassettes from other manufacturers

Not compatible with:

• Shimano 12-speed MTB with Micro Spline
• SRAM XD / XDR
• Campagnolo

Micro Spline

Compatible with:

• Shimano 12-speed MTB cassettes with a 10-tooth sprocket

Not compatible with:

• older Shimano HG cassettes
• SRAM XD / XDR
• Campagnolo

SRAM XD / XDR

XD (MTB):

• for SRAM 11-/12-speed MTB cassettes with a small 10-tooth sprocket

XDR (Road/Gravel):

• for SRAM 12-speed road and gravel cassettes

Neither is compatible with:

• Shimano HG and Micro Spline
• Campagnolo

Campagnolo

Compatible with:

• Campagnolo-specific cassettes

Not compatible with:

• Shimano / SRAM HG
• Micro Spline
• XD / XDR

What should you do if the freehub body is not compatible?

1. Replace only the freehub body

Many wheels offer replaceable freehub bodies. This is often the most affordable solution.

Proceed as follows:

1. Check which hub you have
2. Check whether the manufacturer offers replacement freehub bodies
3. Choose the appropriate standard, such as HG, XDR, or Micro Spline
4. Have it professionally installed or install it yourself

You can find compatible hubs and accessories here: Hubs & Accessories.

2. Replace the complete wheels

If your wheels are already older or you’re planning an upgrade anyway, it may make sense to buy a new rear wheel or wheelset with a compatible freehub body directly.

This is often worthwhile for:

• Upgrade to 12-speed MTB
• Switch to AXS for road or gravel
• Upgrade from entry-level wheels

Here you’ll find compatible models:

• Wheelsets & Wheelsets
• Rear Wheels

3. Stick with the existing system

If your drivetrain works well and you’re not planning a complete upgrade, it’s often easiest to stick with your current freehub standard and simply choose a new cassette in the same system.

Here’s a direct link to our cassettes.

Typical real-world examples

Older road bike with 10-speed Shimano

If you ride a 10-speed Shimano 105, your rear wheel will very likely have a Shimano HG freehub body. You can then easily fit another compatible 10-speed cassette.

New MTB with Shimano Deore 12-speed

A modern MTB with Deore 12-speed will generally have a Micro Spline freehub body. You’ll then also need a compatible Shimano 12-speed MTB cassette with a 10-tooth sprocket.

Gravel bike with SRAM Rival eTap AXS

If you ride a modern gravel bike with SRAM Rival AXS 12-speed, it will usually have an XDR freehub body. So when buying new wheels, you should specifically look for XDR.

Conclusion - How to quickly find the right freehub body

If you want to find out which freehub body is compatible with your wheel, it’s best to proceed as follows:

1. Check the current cassette and groupset
2. Identify the wheel or hub model
3. Inspect the freehub body
4. Check the manufacturer’s specifications and product description

If you’re unsure, simply take a few good photos of the cassette, freehub body, and hub and ask us.

Find compatible components directly

Now that you know which freehub body is fitted to your wheel, you can search specifically for compatible parts:

• Wheelsets & Wheelsets
• Rear Wheels
• Hubs & Accessories
• Cassettes & Drivetrain