I have a schwinn prelude that I converted into a fixed gear bike. The bb, however, is making loud clunking noises. It came with the bike, so I am assuming that it is the original equipment.
I have a new bb (just the cups and bearings and lockring, no axle) How big of a project is it to switch it out? Should I take it to the lbs, or can I do it myself? If so, what tools will I need?

Also, what size bb does that bike require? I have a leftover splined bb and crank from another bike and I am wondering if that would fit.

thanks

1. Crank Puller
2. Pin spanner (maybe)
3. Lockring Tool (You need one of these anyhow...)
4. 1/4" bearing balls
5. grease

The parts inside may actually be okay. "Clunk" usually is because it loosens. It is good to have spare parts, though. Hopefully your spindle races are in good shape.

Alternatively, instead of the pin spanner, you may need a different wrench to turn the adjustable cup. You should be able to figure this out by looking at it.

Overhauling the bottom bracket is a meditative exercise and it improves the quality of the ride. Enjoy.

thanks, but i messed with it today and found that it was just the bearings in the left pedal (old piece of junk) so I opened it up, regreased it, and i'm back up and running
I really do need to get some new pedals though