The Wheels Manufacturing 386EVO Bottom Bracket with Angular Contact Bearings is designed for use with 24mm (Shimano) cranks on bikes with a 386EVO bottom bracket shell. The bottom bracket features two sealed Enduro Angular Contact bearings, which are designed to handle both radial and axial loads, providing smooth and durable performance. The Wheels Manufacturing 386EVO Bottom Bracket with Angular Contact Bearings is compatible with Shimano cranks with a 24mm spindle diameter. It installs easily into the bottom bracket shell with no special tools required.