PromptCritical 

I always thought rolling resistance of bearings had mostly to do with the lubrication (heavy grease > lighter grease > oil). Obviously the bearings need to be of a minimum hardness, but can someone enlighten me as to why folks are using ceramic bearings?

Barry2 

The heart wants, what the heart wants !

It’s the result of successful marketing.

Barry

Koyote

Greater sphericity which leads to virtually trivial reductions in drag.

Trakhak

Search says:

Ceramic bearing balls are often used in industrial applications that require high speeds, high loads, and high temperatures. They are also used in the aerospace industry, medical, and automotive industries.

None of those three conditions apply for bicycles, to put it mildly.

base2 

Because the next better thing exists, that's the thing that must be used.

Breadfan

Ceramic bearings are a waste of money for hubs. They don't spin fast enough to even come close to performing what they are made to do. However, I have them in my surf fishing reels for casting well over 100 yards and they really do make a difference for that application. But I get it, the heart wants what the heart wants.

pdlamb

Slightly better deformation, so trivially lower drag.

Slightly lower weight. Some of the most expensive weight reduction available in the bicycle world.

I think I recall seeing a marketing pitch that ceramic bearings were so good they didn't really need lubrication. If I'm not imagining that, another insignificant drag reduction.

You'd think, for something so expensive and so well hidden, they'd come with large stickers to put on the bike frame: "I've got ceramic bearings in MY bike, nyah, nyah!"

prj71

I recently just purchased some carbon wheels with ceramic bearings. I can tell you they are smooth and the wheels roll forever if you spin them when the bike is up on the stand. I have 7 other wheelsets and they are probably a tie with my wheelsets that have Onyx hubs and roll much longer than the other wheelsets that don't have ceremic bearings.

My next move is ceramic bearing bottom brackets from BB Infinite.

MilhouseJ

I'm anxiously awaiting ceramic bearings for my flat pedals. Then I'll be unstoppable.

PromptCritical 

Back in the day, before a criterium race, we'd lube our hubs with oil and plug the drain hole. One could feel the difference when coasting, but it never made any difference as criteriums are much more about tactics and placement at the finish line sprint.

prj71

You just reminded me that I also recently put ceramic bearings in 2 sets of my Time Pedals. Now I am unstoppable!!!

MilhouseJ

Ah, but did you charge them??

smd4

Lighter weight and smoother. What's not to like?

easyupbug 

I come from engineering/maintenance in heavy industry and we only justified using them for corrosion/moisture resistance, and high temperature applications. None of which I have found impacts my bikes.

Troul 

unless you go all the way & have the bearing races also be fitted for the bearings, the benefit[s] are very minimal if any.

rccardr 

I just ordered ceramic bearings for my seatpost.
Catch me now, suckahs!

Pratt

I'll go with the trivial advantage. From what I've read the two least aerodynamic objects are the human body and the spoked wheel both available in. handy combination package on bicycles.

Bill Kapaun

IF one 'feels" they have better equipment, they'll probably up their performance slightly to "prove it".

stoneageyosh

All feeding the micro watt power differential, super weight weenie, “my bike always stays clean” mantra disciples.

Have you tried using your brakes?

Some track riders used oil just to hear the loose balls click as they would roll over, especially as they were just warming up. Sort of saying “my bike is faster than yours” because of no clingy grease. It may have had a slight advantage in pursuit events. Maybe just a psychological edge for some.
At the 1984 Los Angeles Olympics, fifteen minutes before the 4000m Pursuit Bronze medal race, Leonard Nitz bike was brought to Campy Tech Support and needed the bottom bracket redone. Request was for no grease, loose ball with light oil only so it had to go together dry. Three of us, trading A#*%+^#s and elbows, swapped the BB and handed the bike back in ten minutes. It was run down to the start line and Nitz won the bronze. Did it make a difference? Ask Harv.

Koyote

That may have nothing to do with the bearing material...And at any rate is virtually irrelevant with regard to speed.

FBinNY 

IMO, other than the desire to have "the best" one needs to maintain some perspective.

There's no denying that bearing friction varies with both material and quality. But the total amount of bearing drag of even the worst is trivial compared to total drag on a bike, which comes from wind, tires, and bearings, in order of importance.

Also, among good quality bearings, under bike conditions, the viscous drag of the lubricant is much greater than any difference in the bearings themselves. Also don't forget about the friction of the lip seals on typical bearings.

IMO, if you want the absolutely lowest drag, pry off the seals, and replace the grease with oil. Of course this might cost you some wear, and really won't make a material difference, but the psychological boost from thinking it would might matter.

smd4

Taking together all the incremental benefits of the small weight and friction savings of our upgrades by definition should result in some cremental gains.

Trakhak

For anyone who wasn't following American bike racing back then and is puzzling over who this "Harv" character is who suddenly showed up at the end of the post, he was usually referred to in print as Leonard "Harvey" Nitz (complete with quotation marks). Why? I don't know.

stoneageyosh

Thanks for the follow up.

MilhouseJ

Where's the fun in that???