Shimano BB-UN300 Bottom Bracket
Best reliable component for everyday bicycle maintenance and upgrades.
A reliable square taper bottom bracket for your bike. It offers a hollow spindle for a lighter build and fits standard 68mm English threaded shells. Ensure you have the correct JIS square taper cranksets and remember to purchase fixing bolts separately.
$29.99
at
Big Sky Cycling
Who it's for
- Everyday riders seeking dependable, low-maintenance cycling components.
- Budget-conscious cyclists and those maintaining older bikes.
- Home mechanics and riders preferring hassle-free component swaps.
Who should skip it
- Performance-oriented riders and weight-weenies prioritizing minimal bike mass.
- Riders wanting to upgrade to modern hollow-spindle cranksets.
- Aggressive riders and powerful sprinters demanding maximum power transfer.
Performance breakdown
Weather resistance
Sealed cartridge design effectively locks out mud, grit, and road spray.
Maintenance requirements
Install it and forget it; this unit requires zero ongoing adjustments.
Compatibility
Standard square taper interface fits a vast range of legacy cranksets.
Structural rigidity
Chromoly steel axle provides a stiff, stable platform for efficient pedaling.
Installation ease
Straightforward threaded design makes swapping out old units a simple task.
Serviceability
Non-serviceable sealed bearings mean full replacement is required when worn out.
Key Specs
Spindle Type
Square Taper JIS
Axle Material
Chromoly Steel
Bearing Type
Sealed Cartridge
Shell Width
68 mm
Spindle Length
113 mm
Thread Specification
1.37 inches
Frame Interface
English
Water Resistant
Yes
Serviceable Bearings
No
Know before you buy
Still have a question?
Ask Metto anything about the Shimano BB-UN300 Bottom Bracket before you decide.
