Ceramic bearings wearing out?

[Master50]

I have a couple of sets of Campy wheels in the household stable but my Shamals have ceramic bearings and I am constantly tightening the bearing adjustor. I just change the balls to ceramic 5/32" balls from the original steel.
Anyone think the ceramic bearings are shrinking?

 

[twothirds]

In a ceramic set up the races will wear before the balls do, so you might want to check that. Or your adjuster keeps loosening.

 

[Fatclimber]

...Or your adjuster keeps loosening.

This sounds like the most probable culprit. I had a rear wheel that was impossible to maintain bearing preload. Even after my LBS 'fixed' it the same thing kept happening. It was a poor design. No idea about the Shamal's.

 

[Master50]

My wife's bike has Shamals with steel bearings and I never adjust her hubs. I checked the adjustment of my hubs by putting a paint dot at the adjustment. The wheel got loose and it is clear that I had to turn the adjustment 1/8 of a turn to take out the slack. I have done this several times, each time tighter.
So last night I put the steel balls back in and took note of a couple of things. The races are worn as the polished surface has grown. I looked at the balls too and a lot of them have developed rough surfaces so they are eroding but not enough to measure. Both are within a thousandth of an inch the same diameter.
The grease is a lot darker than I would have expected too. When I changed the bearings the original grease was 3 years old and mostly white. I regressed my bearings last fall and the grease is black since then. This is the bike that isn't getting out in the winter. It has been hanging since November.

I am completely rethinking ceramic bearings as a simple replacement. Campy races are hard and well machined. I have never seen this much wear in campy bearings before. The ceramic balls are very hard too and it seems they may be of less than perfectly smooth or they have been damaged along the way.
They did not really change the rolling resistance either. I always used to go downhill faster than most.
I am not ruling out the use of ceramic bearings but maybe not as a ball only.

 

[Fiemme]

Ceramic is an abrasive. What you are expereiancing is the ceramic bearings grinding out the steel cups. Ceramic bearings are only good when heat is involved. They should never be used on bicycle parts. This again is another product and marketing BullS**T that has everyone fooled. Use good quality hardened steel bearings with grease and possibly some copper based anti-sieze. Check your wheel bearings and re-grease atlaest every 6 months. More frequently if you ride in muddy wet areas.

Cased Bearings will also wear the casing quicker.

 

[twothirds]

Ceramic is an abrasive. What you are expereiancing is the ceramic bearings grinding out the steel cups. Ceramic bearings are only good when heat is involved. They should never be used on bicycle parts. This again is another product and marketing BullS**T that has everyone fooled. Use good quality hardened steel bearings with grease and possibly some copper based anti-sieze. Check your wheel bearings and re-grease atlaest every 6 months. More frequently if you ride in muddy wet areas.

Cased Bearings will also wear the casing quicker.

+1 to this.

You get the longest lasting wear out of two surfaces when one is only slightly harder than the other. Ceramics being much harder than steel will increase the rate of wear within your bearing system. Ceramics should also only be used in a full ceramic set up, balls and races. As Fiemme mentioned, they are best used in applications of heat where the steel usually gets softer and thus wears faster due to softening and deformation of the metals.

 

[Bustedknuckle]

I have a couple of sets of Campy wheels in the household stable but my Shamals have ceramic bearings and I am constantly tightening the bearing adjustor. I just change the balls to ceramic 5/32" balls from the original steel.
Anyone think the ceramic bearings are shrinking?

You are wearing the cones and cups, rapidly, why you need to adjust frequently. Unless the cups and cones are hardened, like Cult stuff, you will grind the mild-ish steel cones and cups to dust.

Ceramic bearings on bicycles(designed for high speed, high temp, high pressure situations) are a hoax. Complete waste of money in spite of the marketing BS by some ceramic bearing places.

 

[Master50]

You are wearing the cones and cups, rapidly, why you need to adjust frequently. Unless the cups and cones are hardened, like Cult stuff, you will grind the mild-ish steel cones and cups to dust.

Ceramic bearings on bicycles(designed for high speed, high temp, high pressure situations) are a hoax. Complete waste of money in spite of the marketing BS by some ceramic bearing places.

First
I agree there races and cones are being eroded by the harder ceramic balls but the races and cones are hardened and while relative to ceramics the steel is softer I think referring to it as Mild Steel would give an incorrect impression of campy bearing surfaces. I will replace the races and cones soon.

I would still disagree that ceramics are a HOAX but I am changing my mind on how to benefit from their lower rolling resistance. Looking at some of the high end wheels like Campy's Cult (CULT is more than an appropriate name) wheels.
Specific matched ceramic bearings and only oil as a lube. Roll down tests sure are impressive. It has become clear to me that ceramic bearings need to be races and balls combined. Clearly the change the balls only strategy only wears out the bearings faster. Hardness of the steel races aside.

 

[twothirds]

Is this a loaded roll down test, with you on the bike, or are you just spinning the wheels in the stand and timing how long they roll for?

 

[Bustedknuckle]

First
I agree there races and cones are being eroded by the harder ceramic balls but the races and cones are hardened and while relative to ceramics the steel is softer I think referring to it as Mild Steel would give an incorrect impression of campy bearing surfaces. I will replace the races and cones soon.

I would still disagree that ceramics are a HOAX but I am changing my mind on how to benefit from their lower rolling resistance. Looking at some of the high end wheels like Campy's Cult (CULT is more than an appropriate name) wheels.
Specific matched ceramic bearings and only oil as a lube. Roll down tests sure are impressive. It has become clear to me that ceramic bearings need to be races and balls combined. Clearly the change the balls only strategy only wears out the bearings faster. Hardness of the steel races aside.

That's like saying BB 30 cranks are stiff and aluminum chainring bolts are light. It implies that standard cranks are soft and steel CR bolts are heavy, neither of which is true.

Ceramic, being VERY expensive unless these asian balls are mated to very soft steel cones and cups, ala sram(mild meaning they are way softer than hardened cones and cups in CULT, for instance)-do make a teeny, tiny difference in roll down tests, unloaded wheels.They show an improvement but it makes zero difference in a road bike, on the road, in the hands of any enthusiast or even a pro. Races aren't won because of ceramic nor lost because of the steel bearings. Enthusiasts buy them because of marketing.