Full Ceramics

Good steel hub bearings lose up to 0.37 W at 44 km/h (both wheels). Good ceramic hub bearings improve bearing power loss by ~4%. This is 0.015 W. Hub seal rolling resistance is not altered. Let us be really conservative and say that you can maintain 44 km/h at 350W total power output (I couldn't, probably ~400W). This is a 0.004% total power saving from ceramic bearings, for only ~A$300!!!! Crikey, where's my wallet?
For those that need it: [/irony].

Full ceramics have been used in other applications and are relatively wear and corrosion resistant. Packed tightly, I don't see how they would necessarily shatter. here is some information that will hopefully shed light on your question:
[img]xlbbearings.comcoin 1.gifOpen ↗[/img] Full ceramic(All-ceramic) bearing of ZrO2 material
Full ceramic bearing have excellence performance as special electrical and magnetism resistance, wear and corrosion resistance, lubrication and maintenance free when working, especially high and low- temperature application. etc. could be used in awful environment and specially condition. The rings and balls made by full ceramic material:ZrO2, as a standard constructor, the cage made by PTFE, generally we also could make the cage with GFRPA66-25,PEEK,PI,AISI,US304,SUS316,Cu,etc

[img]xlbbearings.comcoin 1.gifOpen ↗[/img] Full ceramic(All-ceramic) bearing of Si3N4 material
Full ceramic bearing made with Si3N4 have some better performance than ZrO2, the rings and balls made by full ceramic material:Si3N4, as a standard constructor, the cage made by PTFE, generally we also could make the cage with GFRPA66-25, PEEK, PI, Phenolic Textolite Tube ,etc. Compares than the material of ZrO2, The SiN4 ceramics bearings could endure heavier load and could be used in higher temperature environment. Also we could offer precision ceramic bearing which generally used in high-speed and high-rigidity spindle. the manufactured clearance could be P4 TO UP grade.

[img]xlbbearings.comcoin 1.gifOpen ↗[/img] Full ceramic (All-ceramic) bearing of full complement balls
Full ceramic bearing of full complement balls has an add-ball gap on its side. Because using no frame design, the bearing able to install more ceramic balls than the standard construction, so the heavier load ability increased more. In addition, to avoid the limited of the frame material, this bearing same as the full ceramic bearing of ceramic cage has corrosion resistance and high temperature application. This series of bearing is not for high –speed choice, it should be to install on the unforced side.

[img]xlbbearings.comcoin 1.gifOpen ↗[/img] Full ceramic(All-ceramic) bearing of ceramic cage
Ceramic cage has excellence performance as wear and corrosion resistance, high strength, lubrication and maintenance free when working. Adopting the ceramic cage, Ceramic bearing can be used in the most inclemency environments as corrosive, low temperature, high vacuum. The normal used ceramic materials are ZrO2, Si3N4 or Sic.

vio765 said:

Ok, some of you know i am really big into the future of cermic bearings, dimpled goodies, etc. I present to you this question:

full ceramics are entering the market. what is you opinion of this technology? we all know these bearing are super expensive, so keep that factor out of your response.

my opinion: right now they are untested. no concrete data or opinions from anyone. but they seem to offer superlow friction which could prove noticable gains in spped. i fear that if used on the road, a hard hit would shatter them. they would be fine on the track for now.

artemidorus said:

Good steel hub bearings lose up to 0.37 W at 44 km/h (both wheels). Good ceramic hub bearings improve bearing power loss by ~4%. This is 0.015 W. Hub seal rolling resistance is not altered. Let us be really conservative and say that you can maintain 44 km/h at 350W total power output (I couldn't, probably ~400W). This is a 0.004% total power saving from ceramic bearings, for only ~A$300!!!! Crikey, where's my wallet?
For those that need it: [/irony].

where did you get this data? seems awfully low. steel bearings losing .37W @ 44km/h?

Other applications which use ceramic bearings do not necessarily include the same degree of impact loading so you cannot draw any conclusions about whether they'll shatter from other sources. I've cracked steel balls so we don't have a large margin of safety.

Also, do not assume they would not have been developed if they didn't offer a significant performance advantage. There are other reasons they are needed. Some industrial applications need nonconductive bearings and some bearings are required to run in environments which would corrode metal bearings.

vio765 said:

where did you get this data? seems awfully low. steel bearings losing .37W @ 44km/h?

From this site.

Fella seems to know what he is talking about, but clearly this is not peer-reviewed data at first hand. Note that the total hub rolling resistance is greater, as the seals contribute. Most sources seem to overestimate the size of bearing drag by at least one order of magnitude, perhaps because they are not distinguishing between bearing drag and total hub drag, although I don't think that seal drag is much bigger.

garage sale GT said:

Other applications which use ceramic bearings do not necessarily include the same degree of impact loading so you cannot draw any conclusions about whether they'll shatter from other sources. I've cracked steel balls so we don't have a large margin of safety.

Also, do not assume they would not have been developed if they didn't offer a significant performance advantage. There are other reasons they are needed. Some industrial applications need nonconductive bearings and some bearings are required to run in environments which would corrode metal bearings.

no argument here! but what about cycling specific applications? would you aggree that full ceramics can provide a noticable advantage in speed?

artemidorus said:

From this site.

Fella seems to know what he is talking about, but clearly this is not peer-reviewed data at first hand. Note that the total hub rolling resistance is greater, as the seals contribute. Most sources seem to overestimate the size of bearing drag by at least one order of magnitude, perhaps because they are not distinguishing between bearing drag and total hub drag, although I don't think that seal drag is much bigger.

thanks for the link! according to the site, it does not take much to move these things in circles. but something i just thought of: if these numbers were "learned" via testing and under zero load, i would kinda ignor the data. but what if these bearings are installed in some wheels and asked a 70kg rider to ride for a while? you think those small numbers would be amplified like the loses from the chain and tires?

vio765 said:

no argument here! but what about cycling specific applications? would you aggree that full ceramics can provide a noticable advantage in speed?

I don't have any data but I doubt it. Maybe if they could be run without lube, but they can't. Even so, it wouldn't add up to much.

Why not direct your attention putting together the best training program and most cost effective equipment for your bike and budget? For example, you could get a Red Ryder and 2500 bb's for less than $50, and start dimpling your wheels and frame tubes.

Or get skinwalls, maybe experiment if latex tubes help, maybe get tubeless...

vio765 said:

if these numbers were "learned" via testing and under zero load, i would kinda ignor the data. but what if these bearings are installed in some wheels and asked a 70kg rider to ride for a while? you think those small numbers would be amplified like the loses from the chain and tires?

I don't think that anyone would bother testing an unloaded hub, that would be a very elementary error, but I concede that I don't know for sure.
I'm not sure what you mean about amplified power losses.

Yup, BTW both types of bearings need seals and lube when used in a bike. Does the data include seals and the appropriate lube?

garage sale GT said:

Yup, BTW both types of bearings need seals and lube when used in a bike. Does the data include seals and the appropriate lube?

As I understand it, the drag data are for lubricated bearings in the absence of seals. Seal drag would be the same with both bearing types, obviously.

garage sale GT said:

I don't have any data but I doubt it. Maybe if they could be run without lube, but they can't. Even so, it wouldn't add up to much.

Why not direct your attention putting together the best training program and most cost effective equipment for your bike and budget? For example, you could get a Red Ryder and 2500 bb's for less than $50, and start dimpling your wheels and frame tubes.

Or get skinwalls, maybe experiment if latex tubes help, maybe get tubeless...

why a BB gun? SHOTGUN!!!! lol. seriously, this whole thing is out of curiousity. i never said i was actually going to buy full ceramics. and the topic at hand is providing thoughts on full ceramic bearings, not money or fitness programs.

From HED:

"There was a measurable drag difference between ceramic bearings and steel bearings when we tested unloaded wheels, but the difference was small enough that we could not measure it on a loaded wheel ."

There are more details on the link

http://www.hedcycling.com/wheels/ceramicbearings.php

do y'all think it would be reasonable for one to save 5 watts if one were to replace all the rotating goodies with FULL ceramics? i think if someone were to do this, 5 watts saved could be realistic. hey, why doesnt someone who has more money than me go try this and get back with the rest of us!?? lol.

According to this, we'd save 4 to 6w just by using 2 latex tubes. Many tyres on here are tested with both latex and butyl tubes, and the latex cuts about 2 to 3w, depending on the tyre

http://www.biketechreview.com/tires/images/AFM_tire_testing_rev4.pdf

vio765 said:

do y'all think it would be reasonable for one to save 5 watts if one were to replace all the rotating goodies with FULL ceramics? i think if someone were to do this, 5 watts saved could be realistic. hey, why doesnt someone who has more money than me go try this and get back with the rest of us!?? lol.

It seems that ceramic bearings save about 4% bearing drag. To save 5W, bearing drag would have to be 125w at that arbitrary speed. That sure as anything isn't the case. It seems that the total hub bearing drag at 44 km/h is less than 1W.

i just found something interesting. there is a wind tunnel in colorado that caters to our aerodynamic needs. they charge $1075 for a test that will improve TT position. it sounds like that would be money well spent versus full ceramics. but there is no denying that BOTH (wind testing and ceramics) are super-bling. how embarrising would it be to brag on the start line for some race about full ceramics AND THEN GETTING DROPPED!?

vio765 said:

Ok, some of you know i am really big into the future of cermic bearings, dimpled goodies, etc. I present to you this question:

full ceramics are entering the market. what is you opinion of this technology? we all know these bearing are super expensive, so keep that factor out of your response.

my opinion: right now they are untested. no concrete data or opinions from anyone. but they seem to offer superlow friction which could prove noticable gains in spped. i fear that if used on the road, a hard hit would shatter them. they would be fine on the track for now.

Well, sorry to bring expense into it, but you only really need one ceramic ball in the set to achieve nearly all the advantages. So that would save a lot of money.

anyone read the VERY short paragraph in the the June edition of Bicycling about ceramics? page 136 at the bottom. "Their measurable benefit is small, but small isn't nothing." this is about what i expect. replacing hub bearing with cheap Grade 5 hybrids wont do anything IMHO. however, throw in Grade 3 FULL CERAMICS in the hubs, BB, pedals, and pulleys and we may have something; perhaps a few saved watts. this, again, isnt much. but in my area, our top 2-3 TT guys win or lose to each other by less than 30 seconds on a routine basis. i know that one of them has claimed that he has hit his genetic peak. im pretty sure the other two have too (or are very close). they all have the highest quality machines and parts. the only way for them to get faster is either wind tunnel testing, ceramics, altitude training, or EPO. i guess my point is that around here, a few watts from ceramics sounds worth the price. ok, you talk.