Shimano
UN300 Square Taper Bottom Bracket
The Shimano UN300 Square Taper Bottom Bracket offers reliable durability and smooth operation for your bicycle. This versatile component ensures compatibility with a wide range of frames and cranksets, providing flexibility through multiple configurations. It accommodates various shell widths and a broad range of spindle lengths, making it an adaptable choice for many bike builds. Available in Standard (50mm Chainline) or Chain Case (48.8mm Chainline) styles, it's designed for dependable performance on any ride.
Owner Satisfaction
4.5
/ 5
Category Rank
1013
/ 2100
#1013 in Components
Spindle Interface
Square Taper
/ Square Taper
Who it's for
- Excellent Durability
- Exceptional Value
- Zero Maintenance Required
Who should skip it
- Lower Stiffness Profile
- Relatively Heavy
- Non-Serviceable Design
Key Specs
Spindle Interface
Square Taper
Shell Width Options
68mm, 73mm
Spindle Length Range
107mm to 127mm
Chainline Option 1
50mm (Standard)
Chainline Option 2
48.8mm (Chain Case)
Model Number
EBBUN300B07X
Features
- Durable Shimano quality
- Smooth square taper interface
- Versatile chainline options
- Broad crankset compatibility
- Accommodates various shell widths
- Multiple spindle lengths available
- Reliable performance
- Adaptable for many builds
What customers say
The Shimano UN300 bottom bracket earns high praise for its exceptional reliability and outstanding value. Cyclists consistently highlight its robust construction, which often surpasses original equipment durability over many miles of varied use. A key feature is the sealed cartridge design, effectively blocking dirt and moisture to ensure a long service life with minimal upkeep. While it uses older square taper technology, users appreciate its dependable, smooth pedaling performance for recreational and commuter bikes. Installation is generally straightforward. For those seeking a high-quality, long-lasting drivetrain foundation at a competitive price, the UN300 is overwhelmingly considered an excellent, dependable choice.
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