I had a new BB (105 Hollowtech II) towards the end of June, and last ride out I got it into my head that the bearings were shot- rumbling noise and seemed to be a bit too much resistance/drag in the BB. (I don't really know how I'd decided that any resistance would be in the BB rather than the rest of the drivetrain and/or my legs, but that's what I reckoned!)

Anyway, last night I had a look and spun the cranks with the chain off- no noise, but it did seem a bit sluggish and it would stop spinning very quickly when I let off pushing it. I did the same with my commuter and the cranks spun much more easily and for longer.

So I guess the question is- can they really have got worse over a few months, or were they always this way and it's all in my head? I did have one pretty wet ride a few weeks ago but other than that it's all been dry, and it's probably only done a few hundred miles since new.

And on another note, are replacements pretty much interchangable- would, say, a Hope BB work OK with my existing cranks?

is your comuuter on HT2 bearings as well – I never get more than a couple of turns out of HT2 BB's on mtb or road bikes even when new.

sq. taper seem to carry on spinning for days.

is your comuuter on HT2 bearings as well – I never get more than a couple of turns out of HT2 BB's on mtb or road bikes even when new.

sq. taper seem to carry on spinning for days.

No, actually the commuter is square taper! But I guess that was my question- I'd never really compared them before, and then last ride it just seemed draggier than it did before but with pretty little time/use. If that's just the way they are I guess I'll just have to man up!