Originally Posted by
ivangobike
I largely disagree, when I was more novice 3 years ago this would have been extremely helpful knowledge to go by. I hope others can find this info instead of having to struggle with understanding how a BB could be so seized without being corroded at all, along with how to approach such BBs. Many cheap bicycles get lots of work done on them all the time in thousands of shops worldwide, some go through multiple sealed cartridge BBs before they retire.
Above all, this should be a wake-up call that we should stop repacking this stuff.
I may not go quite that far. While cup and cone BBs are now only on the cheapest bikes in the 1st world, the 2nd and 3rd world are mostly cone and cup BBs. And I've rebuilt them a half dozen times on bikes, and the cups held up fine. I'm sure you'd find the same talking to folks in classic and vintage. Possible issues:
- Just like 7 and 8 speed chains, which should be more durable because wider than 10/11/12 speed, they are now less durable because the former has poor material, the chainmakers are putting their best steels and surfact finishes into the latter. (See results in Zero Friction Cycling, chain tests.) So my implication is, cups and spindles now may be of worse quality than in the past, because cartridges have taken over 1st world bikes.
- Some have said the bearings were too tight; If spinning the spindle with fingers feels notchy, yes. But less than that, no, proper preload is critical for bearing durability. With any slack, load at a given time goes into 2 or 3 bearing balls on each side. With proper preload, that increases to almost half or 180 degrees of bearing balls on each side, greatly reducing peak bearing loads.
- Seals matter; Lots of cheap cone and cup BBs have no seals, easy for water and grit to get in there, and yeah, even good cups will abrade quickly under those conditions.
- Threaded cups are still better than stamped, pressed in cups for ashtabula (1-piece) cranks, those are thin enough and low strength enough to fracture when a kid doesn't lay the bike down gently but just drops it, the pedal hitting concrete hard enough to do that.
- Like my dad said with regard to the value of slide rules and the knowledge to use them after a nuclear war, if the world goes to cartridge bearings, we're going to be in tough shape in that circumstance. Like people who don't know how to sharpen a knife. Or know their knots.