Octalink confusion

Quoted post said:

Originally posted by scituatejohn
Shimano has a bottom bracket called ES51 and another one called ES30. They are Octalink V2 bottom brackets. They come in sizes 113, 118, 121, and 126mm. I read elsewhere on the Internet, that these bottom brackets are only for use with FC-M572 and FC-445 cranks. Besides the two additional spindle lengths, what differentiates these bottom brackets from the other Octalink V2 bottom brackets and makes them incompatible to other Octalink V2 cranks? It seems odd that Shimano would want to create this kind of confusion. They already had created enough confusion with the two different kinds of Octalink. Now they may have two different kinds of Octalink V2 to add to the confusion. I also read (here I think) that there are differences between some of the square taper bottom brackets too. Perhaps the path of least bottom bracket confusion would be to use cranks that take ISIS bottom brackets, or are they messed up too?

Isis is not prefect either. There are iso(campy) and JIS(most oriental) square tapers. There are specific octalinkspindle lengths for specific cranks,as well as specific octalink splines for different cranks.
Shimano tells you what goes with what.