122.5mm Cartridge Bottom Bracket (Square Taper)
A 122.5mm cartridge bottom bracket is a durable, low-maintenance solution for a wide range of bicycles, including mountain bikes, hybrids, and commuters. Featuring a sealed cartridge design and JIS square taper spindle, it delivers smooth, consistent performance while maintaining proper chainline alignment.
Popular models such as the Shimano BB-UN300 and Kenli KL-08A are widely trusted for their reliability and ease of installation.
⚙️ Key Features
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Sealed cartridge unit
Protects against dirt and moisture for long-lasting performance
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JIS square taper interface
Compatible with a broad range of cranksets
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Optimized chainline (122.5mm spindle)
Ideal for MTB and hybrid drivetrains requiring slightly wider spacing
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BSA threaded compatibility
Fits most standard threaded frames
???? Technical Specifications
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Spindle length: 122.5 mm
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Shell width: 68 mm (also compatible with some 73 mm setups)
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Thread standard: BSA / English
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Interface: Square taper (JIS)
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Type: Sealed cartridge bearings
???? Ideal Use
- Mountain bikes (MTB)
- Hybrid and commuter bikes
- Replacement for worn or noisy bottom brackets
???? Bottom line
A 122.5mm square taper bottom bracket is a simple, dependable upgrade or replacement that ensures proper chain alignment and smooth pedaling. With proven options like the Shimano BB-UN300 or Kenli KL-08A, it’s an easy choice for riders who value durability and fuss-free maintenance.
