Im going to be buying a Shimano M571 Crankset Shown here now they only bottom brackets i can seem to find are the ES-51 and ES-71. The 51 is designed for the M572 (the black and silver ones) and the 71 is for the XT. I've heard that the 71s do work with LX and dont work with the LX so i think i'll be playing it safe with the 51. Anyways even though they say the Es-51 is for the M572 would it work with the M571 crankset as well?
From what I deduced, having owned the M571 and M572 cranks and ES50, ES70 and ES71 BBs, is that the splines are identical but the M572 crankset needs a much longer spindle to give a proper chainline, 121 mm instead of the older 113mm. The longer spindle lengths are only available in the the ES51 model. The ES71 model only come in 113 and 118 lengths.
An ES71 in 113mm or 118mm (73mm shell) will work with the M571 because that's what I'm running on my MTB now.