When upgrading or building a mountain bike, many riders focus on frames, drivetrains, or suspension—but the hub is one of the most critical components affecting ride quality, strength, and compatibility.

Your MTB hub determines:

• How fast power engages when you pedal
• Which cassette and axle standards your bike supports
• Wheel stiffness, durability, and even ride feel and sound

This guide walks you through how to choose the correct MTB hub based on your existing bike, covering spacing standards, freehub types, spoke interfaces, and brake compatibility—so you can make the right decision with confidence.

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Step 1: Understand Front Hub vs Rear Hub

Front Hubs

• Simpler internal structure
• Main function: smooth rotation and secure wheel positioning
• Fewer compatibility concerns

Rear Hubs (Most Important)

• Contain the freehub system
• Control engagement speed and power transfer
• Determine cassette compatibility (HG / XD / MicroSpline)

👉 Most hub selection mistakes happen with rear hubs, especially freehub and spacing standards.

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Step 2: Confirm Hub Spacing & Axle Type

Your bike frame and fork determine hub spacing. Always check manufacturer specs before buying.

Rear Hub Standards

Front Hub Standards

Key Takeaways

• ✅ Boost (110 / 148) is the most common modern MTB standard
• ✅ Super Boost 157 offers maximum wheel stiffness
• ⚠️ Older bikes may require 135 / 142 / 100 QR hubs

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Step 3: Choose the Correct Freehub Body (Cassette Compatibility)

Your cassette determines your freehub—not the other way around.

Shimano HG (Hyperglide)

• Fits: 8–11 speed Shimano MTB, some SRAM 10–11s
• Features: classic spline + internal thread, widely compatible

👉 Best for older drivetrains or budget MTB builds.

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SRAM XD

• Fits: SRAM 11–12 speed MTB (GX, X01, XX1)
• Features: allows 10T smallest cog, threaded interface

👉 Required for SRAM MTB cassettes with a 10T start.

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Shimano MicroSpline

• Fits: Shimano 12-speed MTB (SLX / XT / XTR)
• Features: 23 fine splines, supports 10–51T cassettes

👉 Only choose this if you run Shimano 12-speed MTB.

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⚠️ XDR Note
XDR is a road standard, 1.85mm longer than XD. It can be converted to XD with a spacer but is not used for MTB hubs.

👉 Learn more: MTB Freehub Guide – Understanding HG, XD & MicroSpline

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Step 4: Spoke Interface & Hole Count (Wheel Build Matters)

J-Bend (Bent Spoke)

• Most common spoke design
• Easy to source replacement spokes
• Typically available in 28H / 32H / 36H

👉 Ideal for trail riding, maintenance-friendly builds.

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Straight-Pull

• No spoke elbow → reduced stress
• Stiffer, more responsive wheel feel
• Usually 21/24/28H, with different hole distributions

Spoke Hole Distribution

• 1:1 → equal holes on drive & non-drive side
• 1:2 → more spokes on drive side for strength

👉 Straight-pull hubs are preferred for performance and racing wheelsets.

If you are using Koova hubs, please refer to our Spoke Length Calculator to ensure accurate spoke sizing.

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Step 5: Brake Interface Compatibility

There are two common MTB disc brake standards:

6-Bolt

• Six Torx bolts
• Most widely used
• Easy to service

Center Lock

• Spline interface + lockring
• Faster rotor installation
• Common on higher-end Shimano systems

👉 Choose based on your existing rotors, not preference alone.

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Step 6: Match the Hub to Your Riding Scenario

If you ride an older MTB

• Non-Boost 135 / 142mm
• HG freehub
• J-bend spokes

If you ride a modern trail / enduro bike

• Boost 148 rear / 110 front
• XD or MicroSpline
• Straight-pull for added stiffness

If you want maximum wheel stiffness

• Super Boost 157mm
• Straight-pull strongly recommended

If long-term service matters

• Choose hubs with available spare parts and easy maintenance

Already know your hub model but unsure which version to choose?
👉 Use our Koova Hub Model Finder

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Why Riders Choose Koova Precision MTB Hubs

✔ Boost & Non-Boost options
✔ HG / XD / MicroSpline freehub support
✔ High-engagement ratchet system
✔ Durable bearings & easy servicing
✔ Excellent value vs premium brands

Whether you prefer a loud, instant engagement for trail feedback or a smoother, quieter ride, Koova MTB hubs let you tailor your setup to your riding style.

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If you have any questions about hub compatibility or choosing the right configuration for your bike, feel free to contact us anytime.