Are they really so much better than steel?

Less friction, lighter, etc...

Yes and no.

Yes in that high-end ceramics can enjoy much lower friction coefficients than steel bearings.

No in that a decent properly-functioning steel bearing is a very small portion of bicycle resistance in the first place, so there's not much watts to save no matter how fancy you get.

Lighter wallet

No.

Less friction? Yes. Lighter? Yes. Worth the absurd premium price? That's for you to decide.

Hambini makes two main points (as I remember it) in the video below:
- most friction in sealed bearings is due to the seal
- ceramic bearings seem to degrade and become worse than steel bearings within a few thousand km (due to the ceramic balls wearing the steel housing)

They seem to come in prettier colors.

No. In practice, most of the friction is from the lubricant, and as mentioned above, the drag from the BB is already tiny. You are better of getting quality tyres and not riding your bike with worn drive train components.

Check out the maintenance required on the ceramic bearings and compare to steel. If I recall, last time I was enamored with ceramic BB the instructions were to remove it and clean it every couple hundred miles. (Actually, this one says every 100 hours now, which isn't as bad as my memory had me remembering)

No thanks.

https://www.sram.com/service/techdoc...et-maintenance

Not worth it, in my experience.

I have Kogel PF30 ceramic bearing. HUGE difference with friction compared to crappy Shimano.

is it worth it for $150? That's for you to decide, but I absolutely love the feeling of smoothness and quietness of my BB.

Yes and no. At best you might save 1 watt. However not all ceramic bearings are better, some are actually worse.

3 years ago friction facts tested this. Here are some of the results. The full results need to be bought.

Friction Facts: measuring bottom bracket drag - BikeRadar Australia

Which crappy Shimano BB did you have, exactly?

ceramic bearings worked great for reducing the noise of the suspension bridges i own

I have a Kogel Ceramic BB and I love it. I don't do tons of extra maintenance to it either. Is it worth a few extra bucks over a standard one of you're actively looking to replace yours? I say yes.

$150 vs $15. My "few extra bucks" definitely is different from your "few extra bucks"

Oh I get them discounted through work, so I don't pay #150 either. 😃

His video on BB30 bottom bracket and conversions is excellent for people new to cycling and all the different versions out there.

I would agree. I had a set of Rotor ceramic bearings with a Dura Ace crankset in 2007. If they were speedier, you couldn't prove it by me.

I actually use ultra-light carbon fiber bearings, which are drilled as well to lighten them even further.

I have full ceramic on the kid's climbing bike.
They should have lighter seals too. They are not useful for dust and water.
Bearing can be replaced for a lot less than most think - <$100.
I can blow the cranks around with my breath if not attached to the chain. Something to do.

MASI2.0 BB in Box.jpg

No. The friction is from the seal and the grease, the bearings themselves only account for around 10% of the friction.

Secondly, they aren't selling ceramic bearings, the protectors are plastic, the racers are metal, and the case are alumunum. Only the balls are ceramic, which wear on the metal racers faster, and overtime, the steel ball with metal protectors etc last longer, and actually better over time.

As per the post above - they generally have lighter non-contact seals. They also tend to have lighter grease / oils.

I guess you could go steal ceramic bearing seals and put them on steel bearings. You could clean steel bearings and replace the lube. Or just cut the seals off the steal bearings and clean and use light oil - you'd likely be worse off than just buying ceramic.
Full ceramic un-lubed un-sealed can be had for ~$20 these days. You are paying for the other stuff.

I do take the seals off my steel bearing on the inside where there in no opportunity for dirt.

But under force and speed that 10% friction number changes. At near static (stopped) the seals and grease are most of it. With 90RPM and 400W on them - or 1,000W+ in a sprint, some riders say they can feel them. Whether they can, or can't that they think they can is a good thing.

The glory of this is only to be found by those hawking ceramic bottom brackets-- to those misguided souls who genuinely think that the steel balls and few dabs of grease in their bottom brackets are the only obstacles keeping them from averaging 20mph. I'm pretty sure I could replace my BB with a solid delrin sleeve and probably lose about 5W of efficiency.

But hey, people buy $150 uber-chains, $300 titanium cassettes, and $500 jockey wheels, too.

Titanium cassettes ate way too heavy, and off topic.