Okay, this is an obviously stupid question, but I haven't found the simple answer after searching the forums tonight. I have an Shimano 4550 compact crank on the way, which is Tiagra grade, I do believe. So my question is this: Will any Shimano integrated bottom bracket work, (Hollowtech II I believe it's called) such Ultegra or 105 grade, or must I specifically use a 4500 series bottom bracket?

I appreciate anyone who could give me such a simple answer. It's been a while since I've been on the bike, long enough that my brand new Ultegra 9 speed is no longer state of the art, and I'm just learning all the new tech.

Thanks!

Or maybe an easier question would be, will any shimano bottom bracket work with any crank, regardless of grade or brand?

All of the new shimano bb's will work for any shimano crank, as well as fsa, race face, etc. The one exception is TruVativ/Sram, which have a 24mm drive side bearing and a 22mm non drive side bearing, referred to as "GXP".

The new Shimano bottom brackets are most (if not all of them) Octalink. Are you saying FSA and Race Face make octalink cranksets? 'cause, as far as I know, Octalink is proprietary and noone else but Shimano has the right to use the interface.

There is no simple answer. IF the BB is square taper, you can find non-shimano manufacturers that make cranksets that will work with it. If it's Octalink, then the only source for cranksets is Shimano.

There's another splined interface, ISIS, which is not proprietary, but Shimano makes no components compatible with it.

They are talking about Hollowtech II bottom bracket, which are outboard bearing type.

Negative! Adventure Components, Ritchey, Cannondale and others make/made Octalink interface cranks.

Cranks yes. Bottom Brackets no.

As to the Integrated bottom bracket for the 4550 compact crankset I believe the answer is yes, all the BB cups/bearing assemblies appear to be the same dimensions. Quality is the variable.

Yes, the outboard bearing type of bottom bracket is what I'm looking at. I just wasn't sure if they were all the same aside from quality.

That helps me out a great deal!

Thanks everyone!

That's good to know.

Not always!