Originally Posted by
Duragrouch
External bearings have been more durable for me, and lower cost, in terms of frequency of cartridge BB replacement, which aren't cheap, versus external bearings, and I'm still on my first set after several years with a lot of miles and it still feels like new. External is also much faster and easier to remove the crank for cleaning or other service, and can be done in the field on a tour with a mere allen wrench, not needing to carry a crank tool. Hollowtech II style is also lighter; usually that costs you in durability, but in this case no; The axle is larger diameter so can be stronger AND lighter, and the bearings are larger so thus more durable.
I'm a retro-grouch, but this design is a true advance. (Provided it has forged one-piece crank arms, and not "bonded" assemblies.) It's. More. Durable. (At least for road use, mountain may be different.) What's my name?
I'm curious what you were doing wrong with cartridge BBs. I've ridden three bikes for over a decade (pausing to knock on wood) without any problems; favorite bike about 50,000 miles, the others somewhat less. IIRC I paid either $35 or $40 for the shop to replace each of two at the beginning of that run, it'll probably be $50-60 if I have to replace them today. I call that durable and inexpensive.