Originally Posted by
Doolittle
I worked as a mechanic at a high-end road/tri shop this past summer and was not impressed with BB30/press-fit in general. Firstly, the bearing life is utterly abysmal. I have seen many bottom brackets that had to be replaced after a single season or less on bikes that were in otherwise good shape. Rotor's BB86 standard is especially poor in this regard as the bearings are simply too small (although Rotor is in general an awful and horribly overpriced company). Overall, I do not think that these BB's are adequately sealed and often seem cheaply made. Having to use plastic cups on a $250 FSA ceramic BB (the crumminess of ceramic bearings is a whole other thread topic) seems simply unacceptable to me.
Secondly, while it does generally work fine, I feel that creaking is far more prevalent with press-fit than say Hollowtech. BB's coming loose was not a chronic problem, but it did happen, particularly with a certain Canadian brand that begins with a C and ends with an O. I feel that in the long-term there could be some problems with repeatedly removing and installing BB's from press-fit frames. Creaking seemed to be less of a problem with alloy frames or frames with an alloy BB shell.
Thirdly, the sheer number of standards is ridiculous! I can't believe the Chris King press-fit BB came with 7 different adapters for the different and seemingly endlessly proliferating standards. I see this as a step backwards from the 68mm shell.
Finally, realistically I doubt most people would notice much of a difference between Hollowtech and press-fit, all other things being equal. Of course, this could be said about much of recent bicycle technology.
I don't mean to say that all bikes with BB30 are garbage or anything like that, and I'm sure many people ride bikes with press-fit BB's without problems. But it strikes me as a sort of technological development for its own sake, rather than responding to any kind of problem (eg. the inadequacy threaded BB's), and is not something I want on any of my bikes.
Didn't the development go along something like this:
- We need a way to stiffen bikes at the BB
- A larger diameter and wider shell would allow larger diameter tubes to converge at the BB thereby giving the required stiffness.
- Oh, and a larger diameter shell would allow a larger diameter spindle so we could keep stiffness while lightening the crank. That's good too.
- Oops, if we make the shell wider, we can't use outboard bearings without changing the Q-factor. So lets use inboard bearings. They will still be wide for spindle support because the shell is wider.
- If we stick with a two-piece crank, how will we attach the bearings inside the shell. There is no exposed surface to put a wrench on to tighten the bearing cup assemblies into the shell. I know, let's just press 'em in.
And the rest, as they say, is history. World's best development? Maybe not, but I think I can see how it came about.