Shimano BB‑UN300 | Square‑Taper Bottom Bracket, BSA Thread

The Shimano BB‑UN300 is a dependable square‑taper bottom bracket built for smooth performance and long‑term durability. All variants feature a clean silver finish and are available in multiple sizes and compatibility options, making it easy to match the correct model to your frame and crankset.

• Simple and reliable square‑taper design

• Sealed cartridge bearings

• Durable Cr‑Mo axle

• BSA threaded cups

• Silver finish across all variants

• Replaces BB‑UN26 and BB‑UN55

• Available in standard, E‑type compatible, and chain‑case compatible versions

• Multiple shell widths and spindle lengths

• Fixing bolts not included (Shimano FC‑E6000 bolts recommended)