thing is with press in bottom brackets if frame on bike is not %100 then they will cause endless fun, heres an interesting clip shows how little the frame needs to be out of line to stress out bottom bracket. 0.1mm, to me thats about the thickness of paint? dont know if that would effect threaded but who knows?
Fun isn't the word I would use to describe it. It's a pain in the arse, and boils down to crap engineering. Theoretically, all this stuff is great - but not if you can't be bothered to manufacture it within close tolerances. The reason comes down to cost; which rises rapidly the tighter your manufacturing limits are because you get more rejected parts and more labour time needed on quality control. If you allow any old shite go out of the factory gate and let the customer worry about it, your costs come right down and any resulting creaking problem can always be blamed on the customer's choice of saddle!
I daresay the fit tolerances in threaded BB's can also vary a lot, especially in brazed frames subjected to a lot of heat during fabrication. It would be interesting for that YouTube engineering bloke to get hold of an old low-end brazed gas pipe roadster frame like my Puch and do some accurate measurements on it for comparison! I suspect the smaller axle diameters and cup & cone bearings of conventional BB's allow misalignment to be absorbed by adjustment so it does not cause any issues. Even the cheapest bikes I ride, that you would not expect to have great factory QC, do not creak!
Pretty pissed at having to do what I feel is a repair on a £3.5k bike - But with Kuota/Shop refusing a replacement frame - I am pretty much out of options
I wouldn't be best pleased at being taken for a mug by someone who had banked a large wedge of my cash and then supplied me with a substandard item either.
The seller of one of my used purchases neglected to mention the collapsed ball race in the BB, but it was a 27 year old £15 bike not a new £3.5k one, and I fixed it at zero cost using the BB taken out of a dumped BSO. You expect and accept some problems with cheap & cheerful secondhand stuff, but I wouldn't accept it on a new bike I had paid a lot of money for. I'll keep riding old-school steel, and opt out of all the grief caused by shoddily made carbon machinery.
