USA Bottom Brackets

USA (American) bottom brackets are the original BMX standard. Two cups press into a large shell, about 51mm, and the bearings sit inside them. They’re tough and easy to find, and you’ll often see them on old-school, retro and entry-level frames. They come in 19mm, 22mm and 24mm spindle sizes to match your cranks.

Check your frame’s BB shell and your crank spindle size before ordering.