Short Description
The Shimano BB-UN300 Bottom Bracket is a durable, maintenance-free square taper bottom bracket designed for reliable everyday performance. Featuring sealed cartridge bearings and a robust construction, it delivers smooth pedalling and long-lasting durability for road, hybrid and commuter bikes.
Key Features
- Durability: Sealed cartridge bearings protect against dirt, water and mud for extended service life
- Smooth Performance: Precision bearings ensure consistent, efficient pedalling
- Compatibility: Square taper spindle fits many traditional chainsets
- Low Maintenance: Fully sealed design requires no adjustment or regular servicing
- Easy Installation: Standard threaded design allows straightforward replacement
Product Overview
The Shimano BB-UN300 is a dependable replacement bottom bracket for bikes using square taper cranksets. Its sealed cartridge bearing assembly keeps out dirt and moisture, helping maintain smooth rotation and reduce wear over time. The narrow body design also provides clearance for cable routing beneath the bottom bracket shell, making it suitable for a wide range of frames. Designed for everyday riding, commuting and general cycling use, it offers a reliable and cost-effective upgrade or replacement.
Specifications
- Brand: Shimano
- Model: BB-UN300
- Thread Type: British / BSA
- Interface: Square taper (JIS)
- Shell Width: 68 mm or 73 mm
- Spindle Length: Multiple options (e.g. 107–127.5 mm)
- Bearing Type: Sealed cartridge
- Material: Steel spindle with alloy / composite cups
- Use: Road, hybrid, commuter and MTB bikes
- Maintenance: Maintenance-free sealed unit
Ideal For
- Replacing worn or noisy bottom brackets
- Square taper cranksets
- Commuter, hybrid and entry-level road bikes
- Reliable everyday cycling and workshop servicing
What’s Included
- 1 × Shimano BB-UN300 Bottom Bracket
Care & Notes
Ensure correct shell width and spindle length before purchase to guarantee compatibility with your crankset and frame. Professional installation is recommended if unsure. Regular inspection of drivetrain components will help maintain smooth performance.
Why Buy From LK Bikes
LK Bikes offers quality cycling components and workshop support from trusted brands, backed by expert advice, dependable service and strong aftersales support.
