Any real point in these for most riders? Any hard figures available on reduced friction from their use or extended bearing life?

They seem to be damn expensive and if the improvement is marginal then are they primarily a marketing ploy from manufacturers aimed at those who think that they have to have the latest and greatest racing parts on their bikes, and damn the cost?

Not sure about extended bearing life, I recently bought a (used) bike that had FSA ceramic bearing BB and one side of the bearings died after I ridden only about 50km! I just replaced it with Shimano and have ridden several thousand trouble free kms since.

Good question. I assume you mean steel rings and ceramic balls as opposed to full ceramic bearings. Ceramic bearings are marketed as better due to lower friction between balls and raceways (the grooves on the inner and outer rings that the balls run in) and longer life. The balls are lighter and harder and generate less friction when in contact with steel than steel to steel contact. What does this mean for the cyclist? Well, it does mean longer life. Ceramic bearings will usually last a lot longer but then they cost a lot more so are there benefits elsewhere?

The effort required to rotate a bearing depends on various things (https://www.smbbearings.com/SMBtechda...ictionaltorque). Most ceramic bearings on the market are made in China with tolerances that are not as good as a good quality Japanese or Western made bearing. The inferior roundness means they will not turn as easily. If they happened to have a poor choice of lubricant (e.g. a high viscosity grease) and the wrong seal type, you could have a much less free-turning bearing than some of the cheap bearings with steel balls.

If you want a bearing to last longer, get the ceramic ones. If you want superior performance, that is more difficult and you would probably need a bearing torque tester to be sure. I would say that a high precision all-steel bearing with correct lubrication and seal type would give less rolling resistance than most of the ceramic bearings out there. We are looking at ceramic bearings but we intend to get some comparative testing done against the precison all-steel type before we decide. Of course to buy an expensive bearing is only really worth it if you perform at a high level on road or track where fractions of seconds make a big difference. If not, save your money and get a standard one.

I hope that helps.

For most of us, ceramic bearings are a silly waste of money for negligible gain in performance/durability.

Kind of what I figured.

I have also wondered about the advantages, if any, of carbon fiber cranksets too. How much reduction in weight compared to high end aluminum and do they have a better fatigue life? I know in the past aluminum cranks could eventually fatigue fail with high strength high mileage riders. Seems that I have read that CF cranks can fatigue fail too.

Ceramic bearings are the cycling communities "R" sticker

I was on a group ride with a guy that had a newly installed ceramic bottom bracket. I think it was the second ride with the new bearings. About 10 miles into the ride, the bearings locked up enough that he could barely turn the cranks. He called for a ride home, so I don't know what happened to the bearings, but I assume a ball disintegrated.

+1 Ceramic bearing in bicycle service are a triumph of marketing over common sense. At best they slightly reduce the friction in components that require almost negligable effort to operate. The wattage needed to overcome hub and bottom bracket resistance with decently adjusted steel bearings is so small that even if ceramic bearings reduced it to zero, you'd never notice.

Yup. It's what I call "digital thinking". As long as you can measure something, there is always a winner and a loser. Digital thinkers don't care about the size of the difference.

Bicycle people LOVE to brag endlessly about miniscule equipment differences. Ceramic bearings are going to be the next big thing.

So what do you guys think about ceramic bearing derailler pulleys?

I have an additional tensioner in my setup, that first operated with a couple of standard bearings mounted low. The fairly well shielded bearings would invariably rust and get stuck. To solve the problem, I've got ceramic bearings. I was impressed by their quality. I could compare them side-by-side with new standard steel bearings and they were smoother by a mile. After I have mounted them, my problem is gone. The bearings operate flawlessly through rain, mud, snow, salt etc. If I had money, I would not mind converting all bearings on the bike to ceramic, provided, of course, they did not bring in any side problems. The tensioner on the return, obviously, does not need to withstand strong forces and this is not the case elsewhere on a bike.

i cant see how there would be a measurable advantage to this, other than in $ and bragging rights.

when ceramics come down in price to, say,3 or4 times the cost of regular steel bearings, then it would almost make sence. It is to minisclule of an improvement for the cost imo. but ymmv.
I wouldnt discount them completely because of the wow factor. I would love to have bearings that smooth. the one draw back I see is that they are (ceramics) so delicate.

How much is it worth to have objective valid evaluation of bearings? And other bike parts as well; sort of a "Consumer Reports" for bicycling. I doubt we'd fund an independent lab. The next best thing seems to be what pro racers use.

Pro racers tend to use what their sponsors provide. For example, you won't see Lance using Dura Ace this year. And somewhat related...you can read this article that details all the changes Christian Vande Velde has to make because he got a new sponsor and has to switch aero bars: https://www.cyclingnews.com/tech.php?...le_team_camp08

Another factor for those thinking outside the LBS box is that ALL bike sealed
bearings are standard sizes, readily available from quality (non Chinese) sources.
Bearing suppliers are all over the internet and if one sticks to industrial suppliers
as opposed to suppliers to bike shops, BMXers, roller blades etc you are highly
likely to get good quality bearings. Bearings are characterized by ID, OD and
thickness and type of seal. These will invariably be exact millimeter sizes. The
existing bearing will have an alphanumeric designater on the seal somewhere that
can give you a head start but the ID/OD/thickness is fundamental.