even een citaat vanuit Weigthweenies forum m.b.t. BB30 vs externe cups:
shimano does not do BB30 because they do not believe that BB30 is a superior standard. they have argued this before, and as a mechanical engineer, their argument does have merits. BB30 gives you a tiny and, to a human, imperceptible increase in stiffness for much much higher complexity in maintaining the system. you get smaller Q factor, yes, but that is not a good enough reason IMO. it is, technically more robust to the elements than outboard bearings, but they are a PAIN to replace if something goes wrong. outboard cransk are much easier to replace, more versatile, and less likely to damage your frame on installation. same goes for PF30, and to an extent, BB86 and BBright as well. shimano will also make less money. so I DO see why they would not support BB30.
BB30 is popular among frame manufacturers because it saves them money. it's much faster and cheaper to purchase an OE spec bearing and press it into the fram than having to machine out steel threaded inserts and bond them into frames. it's a simple case of frame manufacturers versus shimano here. but shimano is sticking to their guns and as the major industry player, they have evrey right and clout to do so.
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