Can it be done? I have a mountain bike that needs a new bb, and was thinking about swapping it to a standard cup bb - is this feasible?

Sure it's possible, if you can find a cup-and-cone bb with the correct threading, spindle length and taper. But why?

+1,

Yes it is entirely possible, but why do it? A cartridge style BB can be purchased for only a few dollars more and will be more durable over time and will require virtually no maintanence.

Get the measurements from your current set-up. Then look for a bottom-bracket that suits you. You can use a square-taper system with loose ball-bearings, or you can look into an external-bearing design such as Hollowtech II from Shimano.

I am biased - I hate cartridge bb's. I love the smoothness of square-taper systems. Or external-bearing ones.

The reason that I want to switch is because the current bike needs a new bb, and I'm a fan of the standard spindle/cup style of bb. They seem to last for a bazillion miles, and only need to be torn apart every once in a while to regrease. In 25,000 miles I haven't had one wear out yet (although I have had to replace balls) - I'm leery of a cartridge that I can't fix.

if that's really yor preference (not that there is anythigng wrong with that), then it will be easy, just make sure the spindle length and taper are the same. and bottom bracket threading. Just three things.

Another way to look at it is you can get a cup & cone BB cheaper, it will last longer and it can be maintained.

A-men to that, plus it better to recycle to rebuild than to replace every few years.

I am a complete retro-grouch, but its hard to not like a cartridge BB. I suppose that the very best (and best adjusted) cup and spindle ones spin buttery smooth like no other. And I do like the ability to tear it down. And I do like knowing that if I somehow manage to live to be 100 years old, I can still be using my old BB set up.

But, there is something to be said for a cheap and easy solution that I can forget about for 6 years.

jim

Buy a Wal-Mart Mongoose and rob it of the BB. Replace the balls in it if you're 'skittish'.

The problem with cup and cone is you can either get really cheap, or really nice. There's not really a "medium" that I'm aware of.

That's true, but I would gladly fork out $20 a shot for a new square taper cartridge BB every few years rather than trying to get a cup and cone adjusted properly. The BB is my least favorite part to service, hands down.