Crank language

[TCoop924]

Hi...Stupid question probably...but what does the "104" in a crank bolt pattern description mean? Such as, "4x104". I know the 4 stands for 4 bolts.

[jonassterling]

104mm = bolt circle diameter, or BCD.

It is the measurment from center to center of the shainring bolt holes.

[TCoop924]

Thanks!