Shimano’s default BB is English threaded.

SRAM’s GXP crankset have English threaded bottom bracket options. (SRAM’s BB30 cranks are incompatible with English threaded bottom brackets.)

So it's the thread that matters?

What is BSA? What is 68mm?

68mm is the width of the shell. BSA means you can get a BB for nearly every crank type - BSA68 used to be standard road format.

68 is the width. That is by far the most common in road bikes. BSA is synomous with English threading. The other option is Italian threading. English is the most common.

If you get Shimano, you will want a a Shimano English threaded bottom bracket.

If you get SRAM GXP, you need a threaded GXP bottom bracket.

Birmingham Small Arms

Thank you!