Ceramic or steel bottom bracket.

Ceramic bearings do have a place in performance bicycles just as they do in other fields. For example, if you are a 600 lb rider, and you often ride in temperatures over 500 degrees F, and your bearings are spinning at 5000+ rpm, then they should hold up longer and provide less friction than steel bearings. In fact, at speeds over 20,000 rpm ceramics really shine compared to steel

Here are other ceramic bearing applications that are just like a bicycle bottom bracket:

Aircraft generators
Biotechnology equipment
High speed machining and grinding spindles
high speed mills
Precision instruments
Pumps and compressors

Also, ceramic bearings are lighter, so weigh your steel bearings (1 gram each for .25"), and deduct about 30% to get your equivalent ceramic weight. So a BB, with 18 bearings, will save about 6 grams.

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