BOX Two Alloy External Sealed Bearing Bottom Bracket

This bottom bracket is designed for frames with a standard BSA (English) threaded shell. It is compatible with both 68mm and 73mm shell widths, making it a versatile fit for most mountain and road bikes using this common standard.

This unit is designed to work with cranksets that utilize a 24mm spindle diameter. It is a direct replacement for many standard external bearing systems, including those from Shimano and other brands using the 24mm interface.

The dual-labyrinth covers act as a physical barrier against dirt, mud, and water. By keeping contaminants out of the ABEC-5 bearings, this design significantly extends the lifespan of the unit and maintains smooth rotation over time.

Yes, it is built to handle challenging environments. The combination of precision-sealed ABEC-5 bearings and the dual-labyrinth sealing system makes it highly water-resistant and durable enough for regular trail use.

The 6061-T6 aluminum cups are cold-forged and CNC-machined to provide a rigid, stable foundation for your drivetrain. This construction ensures precise alignment and structural integrity, which helps improve power transfer compared to plastic or lower-grade alloy alternatives.