Just servicing a mates bike for him and replacing his BB91/XT crankset – I have to admit my bikes are all HTII – I can see some advantages of the pressfit system i.e. bigger axle/BB weld area but it this just to save time and money over the HT II system or do people (i.e. STW massive) think this is a real benefit?

I’m really not sold on the BB30 concept yet. Especially for lower end bikes where people will be working on it themselves, or lower end bikeshops that haven’t even got the hang of HT2 yet let alone anything more tolerance critical.

For road/track I can see it being a great idea, but for MTB, I really don’t see the point (SS/cyclo-cross might be the middle ground), and can see the number of threads on bike forums asking ‘fitting/maintained/why is my bb30 worn out after 5days’ kind of thread appearing more frequently.

What concerns me is the possibility of the pressfit wearing as you change BBs. could write off a frame?

Only real benefit is to mass production. Pop 2 bearings and frame in the machine and hit the footswitch for the hydraulic press. Repeat for headset. Much less fiddly than screwing in bearing cups.

edit: aren’t the pressfit type bearings now using plastic cups, so the cups are damaged rather than the frame?

Yes Andy the BB91 cups I have in my hand are plastic and less likely to damage the frame but I have to ask myself if that makes them weaker and more prone to moving/squeaks etc?