Hondo6

Um, maybe paying a substantial price difference to get a miniscule gain that is likely not even noticeable and might not be even readily measurable?

For non-cartridge bearings (the classic "cup and cone" design), there's also potentially another issue. Ceramic bearing balls are generally harder than steel races (70-90 HRc for ceramic vs 50-70 HRc for most varieties of case hardened steel). That means the order of damage inside a non-cartridge bearing using ceramic balls now is likely to be (1st) cones, then (2nd) cups, and (3rd) bearing balls.

This potential disadvantage also exists for cartridge bearing designs using ceramic bearing balls and hardened steel inner/outer races without a ceramic race insert.

I'd personally rather replace bearing balls than cones or cups, particularly on vintage hubs. So I'll stick with grade 25 or better steel bearing balls, thanks.

smd4

What do you care what I pay?

Adding up all the "unnoticeable" lighter parts has allowed me to shave two pounds off my bike.

Hondo6

I don't. But you asked "What's not to like?" - so I answered that question.

No perfect solutions exist. In life, there are only trade-offs between imperfect solutions optimizing different things.

smd4

Maybe you don't like it. I'm good with it. So--for me--there's absolutely no downside.

Hondo6

Do whatever you like with your bike and your $$$. Just don't complain if the decision turns out to be a bad one.

shelbyfv

If we are still talking about his ceramic bearings I don't see how it could be a "bad" decision. I haven't read of them causing damage.

smd4

There won't be any complaining because there won't be any problems.

Hondo6

This thread is quite new. I have no idea - nor do I particularly care - if/when he installed ceramic bearings in his bike. I don't recall him indicating anywhere above if/when he actually installed them, and I'm not going to take the time to research older threads to find out.

However: as I recall bearing damage usually takes time to develop. And if the decision was to use ceramic bearing balls in a classic "cup and cone" bearing, IMO it could indeed turn out to be a bad decision if it causes premature failure of hard-to-find vintage replacement parts (cups/cones) through the bearing balls being harder than the races and causing premature race wear/pitting/failure.

shelbyfv

As they say, anything's possible!

smd4

I installed ceramic ball bearings in my 7700 Dura Ace hubs during lockdown, four years ago. Also replaced the rear steel axle with a titanium one from an XTR hub. Cost me $100 for that thing. I hope I didn't overspend for a minimal benefit there, too!

I'll let you know when my races shatter.

wheelreason

I sell a lot of ceramic bearings, but none to people I care about...

easyupbug 

Agree, w/ the light cycling loads on the bearing & balls and races are mostly damaged I suspect due to spalling and possibly some brinneling of the races which could take place in a hybrid ceramic bearing with steel races most likely due to lube contamination or lube failure and the ceramic balls would not aggravate these failures or even ameliorate. In a all ceramic bearing in cycling loading the only thing I can see affecting the bearing would be contamination of the lube.

alcjphil

What I wonder about is the actual application. Is this a situation where steel balls are replaced by ceramic balls? Or is it where cartridge bearings are replaced with cartridge bearings with ceramic balls? How much will it cost? How much advantage will there be? If the advantage amounts to fractions of a percent, maybe you should look elsewhere unless the conversion is very inexpensive

mpetry912 

it is probably fractions of a percent in terms of lower "friction". The ceramic balls are harder, and they deform less under load. Probably about the same advantage as you'd get from high end lubrication.

Bearing speed may have something to do with it too. Years ago in the tour Franke Vandenbrouke said he could "feel the difference" with ceramic bearings in his pedals.

/markp

prj71

What do you consider a substantial price difference?

I just recently purchased a carbon wheelset. The difference in price between ceramic and no ceramic hub bearings was a whole $30. I got the ceramic bearing hubs.

Hondo6

Yes. DA7700 hubs use the classic cup/cone bearing design with 9 1/4" bearing balls on each side of the rear axle and 11 3/16" bearing balls on each side of the front. For some reason, both used stainless bearing balls vice the more common chrome steel.

Why stainless bearing balls? Dunno. Ask Shimano.

https://si.shimano.com/en/pdfs/ev/FH...-7700-1654.pdf

https://si.shimano.com/en/pdfs/ev/HB...-7700-1653.pdf

FBinNY 

Sometimes engineering decisions turn on small details. Possibly they went with SS as a form of neglect insurance, especially for all weather users. Or they may have used SS so the balls took more wear vs. the races.

OTOH it might just be a translation error by whoever produced the chart.

FWIW, I'm not a fan of ceramic balls on steel races, but don't see the choice if ball material a big issue either way.

Hondo6

IMO it's doubtful that's a translation error, though that's always possible. I've seen many other older Shimano hub EVs that simply indicate "bearing balls" (or similar wording) vice explicitly calling for "stainless steel bearing balls". My guess is that the translation here calling for stainless steel bearing balls is indeed accurate.

I personally think you may be right regarding using stainless bearing balls to help ensure the bearing balls fail first. In order of expense to repair, for a cup/cone axle bearing setup the least expensive item generally will be the bearing balls (per a quick check on Amazon, about of $0.017 to $0.026 cents each when bought in quantity, and perhaps even less, for G25 chrome steel bearing balls); next the cones; and finally the cups. For that reason, it seems to me you'd want them to wear out/show damage in that order.

G25 bearing balls are so cheap that it makes economic sense to simply replace them with new at each service. Hub cones usually are next, but can be pricey and hard to find - especially for high-end vintage hubs. (Plus, some recent designs have one cone integrated into the axle, like Shimano's FH-9100.) Cups? In general, that means replacing the hub body or the entire hub. For some vintage hubs, finding a replacement body/hub can be quite expensive - if it's even possible.

My issue with using ceramic balls with steel races is that ceramic is typically harder than either the cones or cups - and is also more brittle. Hit a big enough bump, pothole, or other road irregularity and it's at least theoretically possible for a ceramic bearing to chip/spall/fracture from impact while the cups/cones are undamaged. If that happens the resulting ceramic shards/debris (which is harder than the cones/cups) can quickly damage or totally destroy the cones and cups.

Hondo6

For me, it's not a pure cost issue. It's a cost/benefit analysis issue. If there's no significant benefit, why spend the money?

Personally, I think ceramic hub bearings are a total waste. This webpage from BC Precision sums up the advantages and disadvantages of ceramic bearings:

https://www.bcprecision.com/blogs/ne...ramic-bearings

I don't see how any of the advantages listed really apply to the cycling environment. And for cup/cone bearings, having a bearing ball substantially harder and more brittle than its races isn't an advantage.

YMMV. If you want to chase a handful of grams and/or a tiny fraction of a percent of total drag, go ahead and use ceramic bearings; it's your bike and your money. But since ceramic has a density ranging from about 40.7% to 76.5% of CroMo steel - and all bearing balls used in bicycles are far less than 1cm in diameter - the savings in weight (and friction) will be small.

'02 nrs

https://cycling.endurobearings.com/p...e+2024%29#xd15 and https://mailchi.mp/endurobearings.co...s?e=fe732a68e9