Originally Posted by
rpenmanparker
Why does a threaded outboard BB last longer than a pressed in one if the bearings are essentially the same? Say in a metal bottom bracket, wouldn't the pressed in bearing cartridges be essentially identical in environment to the cartridges pressed into the outboard cup? Of course except for the BB386EVO cups, the bearing diameter is smaller in the threaded outboard setup than in the pressed setup. But I don't see how that would matter. A carbon BB shell is a different matter in terms of tolerances, I suppose.
I really have no idea why BB30s require the maintenance they do, or why the bearings need to be replaced as often as they do.
I rarely see problems with Hollowtech II BBs, but frequently need to replace BB30 bearings or silence a creaky one.