I noticed tonight while checking some fasteners on my 1980 Schwinn Traveler that the plastic *adjustable* cup on the UN-54 that I installed 1-1/2 years ago is cracked all the way through.

The thing is, it still rides just fine, with no creaking or any other problems that I can discern. I figure I'll just replace the whole BB with a new one (with non-plastic cups...). There are other things I've been meaning to buy recently, anyhow.

Would you ride on it, carefully, for short distances while you wait on the new BB to arrive via post?

If there is any lateral play - side to side - then No. I'd be afraid it would munge my cranks. Are we talking about a square-taper with loose, or in a retainer, bearings? Or what?

It's a cartridge bottom bracket.

There is no play that I can detect after riding it rather hard.

*edit* Square taper. IRO fixed gear crankset.

I'd ride it. You'll be able to tell if it's loosening up. But carry a cell phone.

Thanks. That'll put my mind at ease.

I'll be sure to spay and neuter my animals!

Those UN-54's suck. Mine cracked the first day, then the opposite side died a month after. I remember finding an alloy replacement cup (plastic side) on universalcycles, but it costs about the same as the whole BB.