BSA is another way of stating English threading; it comes from British Standard Cycle. English threading on road bikes mean a 68mm wide, 34mm inside diameter shell with reverse threading on the drive side. It’s the most common threaded standard employed today. This kit works with 24mm diameter thru-axle cranks, found on Shimano, FSA, Rotor, among others. Choose between two bearings for the cups. Standard Bearings have low drag thanks to hardened-steel races and our Ceramic balls. Coated Bearings have those same balls installed on coated, hardened-steel races for longer life and less bearing drag.