Originally Posted by
Doge
Spinning without load is not what steel vs ceramic is about anymore than rolling a 20PSI tire vs a 100PSI tire would tell you on an empty bike.
Smoothness - that is just lack of grit and round bearings - and viscosity of the lube. All are something, but it is the compression/deformation under load which is why ceramic bearings even exist.
Steel compresses more under the same load. So it is like a lower pressure tire and has a larger contact area.
At high speed - like 1000X what you would see on a bike that flexi - matters. It may matter on a bike too, but while I'm not making claims that are scientific, if not tested under real load, it is hard to say anything.
I was replying specifically to #30.
Its super hyperbole comparing steel bearings to a 20 psi tyre. As mentioned many times already, the friction is from the lubricant and the seal. You might as well get a steel bearing with non-contact seals and lubricate with NLGI 0 grease. Thats how friction is reduced in ceramic bearings as well. Ceramics are no more resistant to grit from lack of sealing than steel bearings. It not hard to say anything unless you ignore already established facts.