BB-UN300 Bottom Bracket - Standard

Product Information

The Shimano BB-UN300 bottom bracket is a solid choice for riders needing a dependable square taper unit for their daily commutes, touring, or even older mountain bikes. It’s a direct successor to the well-regarded BB-UN26 and BB-UN55 models, building on that legacy of reliable performance. Designed for a wide range of applications, this bottom bracket ensures smooth, consistent pedaling, making it a workhorse for various cycling disciplines.

This is a sealed cartridge unit, meaning less maintenance and better protection from the elements, which translates to a longer lifespan. It's designed to integrate seamlessly with JIS square-taper cranksets, providing a stable and efficient connection for your drivetrain.

Features

• Sealed cartridge bearings for long-lasting, low-maintenance performance
• Hollow steel spindle (Cr-Mo) for a balance of strength and reduced weight
• Compatible with JIS square-taper cranksets across a broad range of bicycles

Specs

• BB Shell Interface: English (BSA)
• BB Shell Width: 68mm or 73mm
• Axle Type: Square Taper (JIS)
• Axle Material: Steel (Cr-Mo)
• Bearing Material: Steel
• Cup Material: Aluminum (left), Aluminum/Steel (right)
• Weight: Approximately 301g (specific configurations)