Shimano BB-UN300-K Bottom Bracket - English, 68 x 122.5mm Spindle, Square Taper JIS, For Chain Case

The Shimano BB-UN300-K bottom bracket is specifically designed for bikes equipped with a chain case, providing a reliable foundation for daily commuting and utility cycling. Built with a 122.5mm hollow spindle and a classic JIS square taper interface, it threads securely into standard 68mm English bottom bracket shells with a 1.37-inch inner diameter.

Finished in black, this cartridge unit offers smooth rotation and dependable performance. Please note that crankarm fixing bolts are sold separately.

• Frame interface: English threaded (68mm shell width, 1.37 ID)
• Spindle length: 122.5mm
• Crank interface: Square Taper JIS
• Application: Compatible with chain case setups