When upgrading or building a mountain bike, many riders focus on frames, drivetrains, or suspension—but the hub is one of the most important components for performance.
Your MTB hub influences engagement speed, strength, compatibility, and even the sound of your bike.

This guide explains the key MTB hub standards, including HG, XD, and MicroSpline, plus spacing, axle types, and how to choose the right precision hub for your riding style.

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1. Front Hub vs Rear Hub

Front Hubs

• Simpler structure
• Main job: allow smooth rotation & secure wheel placement

Rear Hubs

• Contain the freehub system
• Control engagement (how fast power transfers when you pedal)
• Determine which cassette standard your bike uses

👉 Most compatibility questions center on rear hubs, especially freehub bodies.

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2. Hub Spacing & Axle Types (Boost, Non-Boost, QR, Thru-Axle, 141, 157)

A clear, table-based explanation for all MTB spacing.

Rear Hub Standards

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Front Hub Standards

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👉 Boost (110/148) is the standard for most modern MTB frames.

👉 Super Boost (157) is for riders seeking maximum wheel stiffness.

👉 If maintaining an older bike, you may need 135/142 or 100mm QR.

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3. Freehub Standards: HG, XD, MicroSpline

Your freehub body determines which cassette your bike can run.

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Shimano HG (Hyperglide)

Fits: 8–11-speed Shimano MTB, many SRAM 10–11-speed
Features:

• Classic spline pattern
• Durable and widely compatible

👉 Ideal 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
• Thread-on interface
• Not compatible with Shimano HG

👉 Choose this if your cassette requires an XD Driver.

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Shimano MicroSpline

Fits: Shimano 12-speed MTB (SLX / XT / XTR)
Features:

• 23 smaller splines
• Required for Shimano 10-51T cassettes
• Enables 10T smallest cog

👉 Only choose this for 12-speed Shimano MTB drivetrains.

Want to learn more about FreeHub? Please check out:

MTB Freehub Guide: Understanding MicroSpline,HG, and XD Standards

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4. Straight-Pull vs J-Bend Spoke Interface

J-Bend

• Most common design
• Easier to find replacement spokes
• Good for general trail riding

Straight-Pull

• No spoke elbow = reduces stress
• Provides a stiffer, more responsive wheel
• Ideal for performance MTB builds

If you are purchasing a Koova product, please refer to the following link to view the installation dimensions for each model and calculate the applicable spoke length.
Spoke calculation

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5. Which MTB Hub Type Should You Choose?

If you ride an older MTB

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

If you ride a modern trail / enduro bike

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

If you want maximum wheel stiffness

• 157mm Super Boost
• Straight-pull recommended

If you’re maintaining your bike

• Look for hubs that offer reliable bike hub service and spare parts availability.

You've already decided on a model number, but are unsure which Koova product to choose. Please refer to: Model Finder

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6. Why Riders Choose Koova Precision MTB Hubs

✔ Available in Boost & Non-Boost
✔ Freehub options: HG / XD / MicroSpline
✔ High-engagement system for instant power
✔ Long-term durability & easy maintenance
✔ Excellent value compared to premium competitors

👉 Whether you prefer a loud engagement sound for trail feedback or a smoother, quieter ride, Koova hubs let you customize your MTB experience.