what he ^ said.
the gusset BB is very, very well sealed + shielded*. and used ‘normal’ size bearings**
(*better than my hope BB)
(**unlike my hope BB)
i’ve done 3000km on my ext24, it’s still like new.
No idea how people get through Shimanos in a couple of months tbh, my bikes get used more than most in worse conditions than most but I still get way more than that from XT/SLX. They don’t like overtightening though…
maybe that’s (part of) the problem?
the seals on my shimano BB’s rely on the cranks being pulled together *just so* – if you don’t pull them all the way together, there’s a gap around the seal, and you can see the exposed bearings.
the small plastic clamping widget makes is difficult to over-clamp the cranks, but it also makes it difficult to pull them all-the-way-together, especially if you’re being carefull.
(it’s easy to leave the gap of death)