End Caps & Conversion Kits – Make Your Wheel Fit Any Frame
Building your dream bike and want to reuse your current wheelset, but the axle standards don’t match? No problem! With the right end caps and conversion kits, your wheels will fit any setup in no time. Whether you’re switching from quick release to thru axle, adapting to Boost standards, or simply adjusting your hub to a new fork – here you’ll find everything you need to stay flexible without compromising on performance.
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At R2BIKE, you’ll find end caps and conversion kits for both front and rear wheels. Whether it’s 12x142 mm, 15x110 mm, or more exotic standards like 12x157 mm (SuperBoost+) – with the right adapters, your wheelset will be future-proof and versatile.
Why End Caps & Conversion Kits Make Your Life Easier
A hub is only as good as its adaptability. With the right end caps and conversion kits, you can:
- Switch axle standards: Convert from quick release (5x100 mm / 5x135 mm) to modern thru axles (12x100 mm, 15x110 mm, 12x142 mm, 12x148 mm Boost, etc.) without buying a new wheelset.
- Use Boost standards: With the right adapters and brake disc adapters, you can upgrade your wheelset to Boost (148 mm rear / 110 mm front) or even SuperBoost+ (157 mm).
- Mix and match brands: Whether DT Swiss, Chris King, or Tune – most high-quality hubs can be adapted with the right kits.
- Save weight: Lightweight end caps made of aluminum or carbon keep your setup lean without sacrificing stability.
What to Consider When Buying
1. Compatibility Is Key
Not every end cap fits every hub. Pay attention to:
- Manufacturer and model of your hub (e.g., DT Swiss 240s, Chris King R45, Tune Kong).
- Axle standard of your frame/fork (e.g., 12x142 mm, 15x110 mm Boost).
- Brake standard (Centerlock, 6-bolt) – when converting to Boost or SuperBoost, a brake disc adapter is often required.
2. Material and Workmanship
- Aluminum: Lightweight, corrosion-resistant, and affordable – ideal for everyday use.
- Carbon: Even lighter, but often more expensive and less durable under extreme loads (e.g., downhill).
- Stainless Steel: Extremely durable, but heavier – perfect for touring or e-bikes.
3. Boost & SuperBoost – What Does It Mean?
- Boost (148 mm rear / 110 mm front): More stiffness, better tire clearance – the standard for modern MTBs.
- SuperBoost+ (157 mm): Even more stability for e-MTBs or downhill bikes.
- Brake disc adapters: When converting to Boost/SuperBoost, the brake disc often needs to be offset to ensure the correct position relative to the brake caliper.
Overview of the Most Important Axle Standards
| Standard | Application | Typical For |
|---|---|---|
| 5x100 mm | Front wheel, quick release | Older MTBs, road bikes |
| 9x100 mm (Thru Bolt) | Front wheel, fixed axle | Cross-country, gravel |
| 12x100 mm (QR12) | Front wheel, thru axle | Modern MTBs, gravel |
| 15x100 mm (QR15) | Front wheel, thru axle | Trail/Enduro |
| 15x110 mm Boost | Front wheel, thru axle | Modern MTBs (from 2015) |
| 20x110 mm (QR20) | Front wheel, thru axle | Downhill, fat bikes |
| 5x135 mm | Rear wheel, quick release | Older MTBs |
| 12x135 mm | Rear wheel, thru axle | Cross-country |
| 12x142 mm | Rear wheel, thru axle | Modern MTBs (from 2012) |
| 12x148 mm Boost | Rear wheel, thru axle | Modern MTBs (from 2015) |
| 12x150 mm | Rear wheel, thru axle | Downhill, e-MTBs |
| 12x157 mm (SuperBoost) | Rear wheel, thru axle | E-MTBs, downhill |