I found this awesome quote in rec.bicycles.tech while looking for setup tips on the old Dura-Ace 7700 Bottom Bracket:
The Octalink crank attachment, its feet of clay, has no preload
between the facets of the square spline and therefore frets (tiny
motion] elastically, even if it has no actual backlash in torque.
Aluminum parts against steel are a classic of this syndrome because
the softer aluminum frets on the steel, and instead of developing
rouge as steel-on-steel does, it makes (hard) aluminum oxide whose
repeated fracture often makes a sharp click.
I haven’t heard your BB, but I have heard such clicks. This may be
your problem and the reason why Shimano gave up on Octalink. Elastic
backlash (absence of press fit) is a phenomenon that escapes
recognition in various mechanical devices and gets passed over in
time, even when the reason is not recognized.
So there you have it from JB himself – Octalinks may develop clicking due to their design. We’ll see. I’m not sure if the weight savings and extra $30 are worth it for the DA BB-7700 vs the BB-5500 but I’m partial to designs that allow rebuild and proper setup/adjustment, so I think I just might go for it paired with a Sugino Cospea compact crankset. In my heart of hearts I want a triple with that 12-21 cassette I’m running, something like a 28-38-48 perhaps. The current 34/44 setup is fine considering I don’t often find myself needing much bigger of a gear than 28+ mph but on downhills it is lacking. The other issue being crossover gears where I often find myself running 34 x 12-13-14 and realize I need something slightly bigger.