Ceramic bearinjgs in bicycles.

Discussion in 'Road Cycling' started by cyclintom, Nov 30, 2018.

  1. cyclintom

    cyclintom Well-Known Member

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    There are some major differences in ceramic and steel bearings. Basically they come down to weight and smoothness.

    The weight of the bearing limits the speed at which it can roll without developing too much heat and breaking down the lubrication. The majority of the weight of a sealed bearing is the races so using ceramic balls isn't going to change the weight of the bearing enough to discuss.

    Ceramic bearings are roughly two orders of magnitude smoother or more round if you prefer.

    However, on a bicycle there is neither weight nor bearing speed to allow any real measurable difference in rolling friction. The fastest turning components on a bike are bicycle wheel bearings and they presently last almost forever since modern sealed bearings don't bleed their lubricant out and allow the slight friction to wear them down over time. This means that unlike industrial high speed uses you really can't tell the difference between the two.

    At one time ceramic bearings cost 1,000 times as much as steel bearings but these costs have been falling rapidly as various companies start tooling up to make them automatically.

    The loadings on roller bearings on a bicycle that the material makes is so little difference that there is a question as to whether even the fastest pro on a time trial bike using ceramic bearings in every possible location could even be able to measure it.

    Of course these pros would use ceramic for a TT bike because they could help when differences are in 100ths of a second. Who could say? The question is should you as Joe Average Rider going to ever make the now 2:1 costs of using ceramic worthwhile?

    That should be your personal choice but it isn't going to show up in your Cat 1 performance.
     
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  2. Froze

    Froze Well-Known Member

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    At least now you're getting your info from the internet instead of your head...how do I know? because I looked for keywords you used on the internet and they align up with what you said, you simply changed the order of the words so they were direct cut and paste stuff. And another way I know you didn't do this off the top of your head is because it's lacking you're typical misspellings and thought arrangement that makes up your personality, you usually misspell words and your thoughts are scattered, so no this is not your work, but at least it's fairly accurate unlike most stuff you've done that I've read.

    I would like to add to what you've said so that the complete story is told.

    Not all bearings, be it steel or ceramic are all the same. The roundness and smoothness that you mentioned has different flavors depending on the quality of the bearings, the best steel and ceramic bearings are a graded from (these grades are for bicycle bearings) 2000 to grade a grade 3, the lower the number the more finer the grade of bearing is which also means it will cost more, also ceramic tends to be on the lower end of the number scale because of the nature of ceramic. Now here in lies the problem; with the Chinese making all sorts of stuff cheap one cannot assume that just because it's ceramic it's going to be superior to a steel ball and run out and get ceramic races because you found them for $50, all the cheap Chinese ceramic bearings have grade factors that are poorer than steel and thus high grade steel will outperform the cheap ceramics!

    The other factor is that you cannot by spinning a crank or a wheel tell if the bearing being used to demonstrate its ability to spin better than another and judge that one is better over another. All a demo has to do is use light oil instead of grease and any bearing will spin freely very well, and you don't don't know what they've done to make it spin freely, in fact no lubricant at all will make them spin even better; then there is another problem with free spinning stuff, if the demo uses a low friction hub that too will make the things spin better. The problem with no lube or light oil is that as soon as a load is placed on the bearings they begin to show their true colors and will take more watts to spin not to mention short life; and with low friction seals they don't seal near as well as better seals and dirt can get into the bearings jacking up both steel and ceramic. In fact MOST ceramic bearings makers use looser fitting seals to come up with their BS that their bearings roll better, while that's true but the looser fitting seals is causing them to roll better and not the ceramic bearings that you're spending your money for. And because the seals are loose fitting dirt will get into the bearings and those bearings will eventually get destroyed. Here is one such video showing the world the wonders of ceramic bearings, note they do not say what lube they are using if any on the ceramic or if they're using thick grease on the slow spinning jockey wheel:

    View: https://www.youtube.com/watch?v=RwtlqCtTzDo


    Another issue is using ceramic bearings in mountain bike riding, ceramic doesn't take to impacts well, so if your crank hits something going offroad, your wheels are striking rocks, etc, the chances are pretty good you will destroy the ceramic bearings on the first strike vs steel won't even be marred by such abuse. So on MTB's it's a complete waste of money to buy ceramic bearings knowing that they may not even make it through one maybe two rides in rough stuff.

    Another problem with ceramic, especially with hybrid bearings (this is where the race is steel and the bearings are ceramic), because the ceramic is harder than the steel the balls will eat the steel races which in turn eats the balls and you have to replace them.

    It must be made known that Shimano makes very poor quality bearings, so to say that your ceramic bearings outlasted Shimano is not a big deal, and this is why pros will switch out the Shimano bearings for something better usually ceramic because they don't have to pay for them. On the other hand the best bearings ever put into stock components came from Suntour, those bearings were indestructible as I can attest to with both my Superbe hubs and bottom bracket never needing bearing replacement even after racing, riding in mountains, and after 160,000 miles of use; I would even go as far to say that those were the best bearings ever made even in the aftermarket world...opinion of course.
     
  3. BrianNystrom

    BrianNystrom Member

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    I have to wonder why Tom posts this stuff, since it's answers to questions that nobody here has asked. It seems more like self-gratification than anything else.

    It's appropriate that you showed a video of jockey wheels, since on most derailleur-equipped bikes, they are the fastest spinning bearings - not the hubs - though the recent trend toward larger jockey wheels and smaller cassette cogs is changing that.

    I'm curious if you've actually seen ceramic bearing failures that can be directly attributed to impacts? I haven't and I strongly suspect that it's a largely theoretical issue that simply doesn't happen in bicycle applications. Between the mitigating effects of tires, suspension and ultimately the failure of rims in worst-case crash scenarios, the impacts on bike bearings are actually pretty minimal. Failures are far more likely to occur due to contamination or improper end-loading.
     
  4. BrianNystrom

    BrianNystrom Member

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    Another surprisingly common problem is hub tolerances, specifically the ID of the bearing seats in hubs. It only has to be too small by a thousandth or two and the inward pressure on the bearing will cause it to bind and fail over time. You can't blame this on the Chinese, as I've had this problem with high-end hubs, too.

    Full ceramic bearings are less susceptible to contamination damage because the ceramic is harder than most contaminants. Contamination will cause increased drag until the contaminant is pulverized and pushed out of the path of the balls. In this way, they are somewhat self-cleaning and you'll see them billed as such. In some cases (again, jockey wheels), they're run without lubricants or seals - or with just shields - in order to allow contaminants to be ejected more easily. How long they'll actually last like this is hard for me to say, as I haven't had enough time with this type of bearing to experience any failures.

    I'm not saying that ceramic bearings offer any real advantage for the average rider (like me) and I'm certainly not willing to pay for ceramic replacements for steel bearings that are working just fine. I've had Campy and FSA cranks that came with ceramic bearing bottom brackets that have held up really well. Whether they've actually been any better than steel bearings in any significant way is anybody's guess.
     
  5. cyclintom

    cyclintom Well-Known Member

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    Brian, I'll let your posting stand for itself. You criticisms are pretty far off.
     
  6. cyclintom

    cyclintom Well-Known Member

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    Or perhaps I should ask you some questions - where did I speak about ceramic bearings breaking from loads? Also - exactly WHAT loads do you think that idler (IDLER) pulleys have on them? You do know that they only carry chain slack don't you?

    Where do you get "contamination" in a sealed bearing? That is normally a word that means that a bearing is breaking down and leaving small metal particles in the races. Since bicycle bearings are so lightly loaded that isn't a problem with any sort of sealed bearing - steel or ceramic. It used to be a problem with open bearings.

    My postings are for general knowledge for those interested in such things. At what point recently have you posted anything that anyone else might be interested in - that is not an insult, but a statement for you to think about.
     
  7. BrianNystrom

    BrianNystrom Member

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    You didn't, Froze did, but I guess it's too much to expect you to figure that out.

    Actually, the upper pulley sees substantial side loads, particularly when shifting from smaller to larger cogs, but I guess it's too much to expect you to figure that out.

    Sealed bearings are not completely impervious to contamination, in particular water intrusion and the particles that water brings with it, but I guess it's too much to expect you to figure that out.

    Unlike you, I don't post things just to try to show that I'm knowledgeable (inevitably unsuccessfully in your case). Rather, I end up correcting the misinformation that you post, but I guess it's too much to expect you to figure that out.

    Notice a theme here, Tom?
     
  8. cyclintom

    cyclintom Well-Known Member

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    Then by all means why do you talk about things I've posted? If you think that there are significant side loads on a idler pulley show me some proof of that. The entire idea of click shifting is that there are only a tiny percentage of the loads that friction shifting had.

    Apparently you wear out sealed bearings all the time. Oh, well, maybe you've worn one out in the last 20 years. So that makes your stupid statement knowledgeable, right?

    Unlike me you post some sort of attempt to argue. Is that why you joined this forum? You have successfully countered absolutely nothing I've posted. You will wear through the brake area of an aluminum wheel before you get sealed bearing failures. Are you suggesting that it would be more economic to buy and replace a rim than to buy a new wheelset?

    I'd warrant that you don't even know how they make a "sealed" bearing with so little fiction.

    You are surprised that some guy in Louisiana is using tubulars and intimate that makes him a real expert in rolling resistance despite all of the data available that contradicts that.

    When it's pointed out that a 2012 picture of a TT bike shows Specialized Roubaix tubulars on it means that the riders uses tubulars and those specifically when that isn't even the TT tire that Specialized makes. And others have lower yet.

    None of this is any big deal but it shows you're arguing just for the sake of arguing. So don't pretend it is otherwise or that you're correcting anything. If you do make a point I'll be the first to agree you're right if Froze isn't there patting you on the back about how great you showed me when he can't even read what you wrote.
     
  9. BrianNystrom

    BrianNystrom Member

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    Because most of what you post is wrong. People who come here deserve to get accurate information, not a bunch of BS spewed by a delusional fool who thinks he knows what he's talking about.

    I never said the side loads were as high as with friction shifting.

    Now you're back to your typical mode of just making things up.

    I've been riding sealed bearing components since the '70's and I've replaced a lot of bearings in that time. As I said previously, the typical failures were due to either water intrusion, improper end loading or improper bearing seat tolerances. Bearings that were not affected by these things have lasted more or less indefinitely.

    Unlike you, I spent the better part of a decade working in a bike shop, literally fixing thousands of bikes and I still work on a variety of bikes today. I've seen more types of bike failures than you will in your entire life.

    No Tom, you constantly post misleading or simply incorrect nonsense and I'm trying to set the record straight so others here don't make costly mistakes based on your misguided posts.

    This is just more proof that you are utterly delusional.

    Where do you come up with this crap?

    What is this even supposed to mean?

    Where did I ever say anything like this? I pointed out that they guy making the WattZit was riding tubulars as a joke, because of your silly tirades against them. Of course, you can't see that...

    Another completely nonsensical statement. Can you even complete a coherent thought, Tom?
     
  10. dabac

    dabac Well-Known Member

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    What an excellent way of summing up your posts!

    ... even If it took a typo to achieve it...
     
  11. BrianNystrom

    BrianNystrom Member

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    It was YOUR typo in YOUR post, Tom. And yes, I agree that YOUR posts are mostly fiction, incoherent fiction.
     
  12. cyclintom

    cyclintom Well-Known Member

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    And yet there you are showing that you don't know how they make sealed bearings with so little friction. Instead you attack a typo.
    You claim that most of what I say is wrong. But you claimed that idler pulley's turned fast (they don't) and they have higher loads (they don't).

    You said, "Sealed bearings are not completely impervious to contamination, in particular water intrusion and the particles that water brings with it,". Everything wears out. In case you're unaware even the rotation of the moon around the Earth is changing its orbit over time. What precisely does that have to do with anything? The overwhelming number of people in the overwhelming number of cases will NEVER wear a sealed bearing out in their lifetime. Pretending otherwise as you attempted to do was argument for the sake of argument.

    You suggest that a sealed bearing would wear out before the braking surface on a aluminum wheel would wear through to unusable and force either a new rim or a new wheelset. That is the sort of crap you're trying to pass off as me being wrong. The wear markers on a Campy or Fulcrum wheel are 1/32nd of an inch deep and you can wear through those in heavy use in one year. And the amount of climbing we do around here means heavy use on all of the descents. And many people buy higher friction brake pads so that they don't have to pull the lever so hard and this wears the braking surface even faster from heat and friction wear. You're not an engineer and you don't know even the most simple things about engineering. I suggest that you don't act as if you do.

    I have actually bought and used these things that I post on. You haven't and are passing out nothing more than opinions. Excuse me but you have to do better than that.

    CampyBob has a screaming fit that a picture he posts of a 2012 TT bike has tubulars on it. He says that PROVES that tubulars are better than tubeless. Then YOU chip in that the guy with the broken down old steel bike has tubulars on it. That didn't look like a joke to me and if you intended it to be a joke you certainly could have done a better job.

    You seem to have no answers than to revert to name calling and mentioning a concussion I had a decade ago. That doesn't say a whole lot for you.
     
  13. BrianNystrom

    BrianNystrom Member

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    QUOTE="cyclintom, post: 3844885, member: 224138"]And yet there you are showing that you don't know how they make sealed bearings with so little friction. Instead you attack a typo.[/QUOTE]
    Tom, YOU attacked the typo, but you apparently still don't recognize that YOU made it, not me.

    Let's see, which turns faster, a 10-tooth idler pulley or a wheel bearing being turned by an 11-tooth or larger cog, which are both driven by the same size chainring (pick any size you want, it doesn't matter). The answer is the idler pulley. As for the loads, I NEVER said that idlers experienced high loads; you made that up.

    Again, you just made up a bunch of crap. I never said that sealed bearings would fail other than for the three specific reasons I stated. In fact I said "Bearings that were not affected by these things have lasted more or less indefinitely." Do you even bother to read anything before you start spewing your nonsense.

    No, I never said anything of the kind; you made it up. Show me the quote, Tom.
    <irrelevant nonsense deleted>

    Well Tom, if you're not suffering the effects of head trauma or other mental deficiency, you're just a delusional fool who thinks people should take what he says as gospel simply because you say it. You refuse to listen to anyone who disagrees with you, even when it's obvious that you're wrong and you know it (or should know it). You appear to have a really difficult time distinguishing reality from what's going on inside your head, as you keep making things up and attributing them to others in an utterly feeble attempt to discredit anyone who points out your errors.

    Either way, I feel sorry for you, as you're obviously struggling to get through life and it must really suck to be you right now.
     
  14. dabac

    dabac Well-Known Member

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    Assuming you by ”click shifting” mean indexed shifting - No.
    The idea of indexed shifting is to get faster clean shifts by removing the need for manual precision positioning of the shifter at every gear change.
    The majority of all indexed shifters works by relying on muscle power applied at the shifter to move the derailer and chain into position at a bigger sprocket/chainring. This also tensions a spring in the derailer.
    This spring then provides the power for the return movement to a smaller sprocket/chainring.
    This is also exactly how friction shifting is powered. Muscle input brings the derailer and chain to a bigger sprocket/chainring and tensions the return spring. The return spring brings the derailer and chain back to a smaller sprocket/chainring when the wire is released.

    Now, although I have successfully mixed derailers from the friction shifting era together with indexed shifters(and vice versa), it is POSSIBLE that a derailer made for indexed shifters MIGHT have a SLIGHTLY stronger return spring.
    But there is NOTHING that would suggest, either by functional analysis or user experience that the forces in one system would be only ”a tiny percentage” of the other.
    The DIFFERENCE being only a ”tiny percentage” would make a lot more sense.

    The introduction of ramped, pinned and shift-gated chainrings and matching sprocket design probably reduced the power need for the shifting system far more than the switch from friction to index shifting.
     
  15. cyclintom

    cyclintom Well-Known Member

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    I agree that the purpose of indexed shifting was to give more accurate shifting but that was only a part of the problem.

    There are ramps cut into the rear cogs that allow the forward motion of the chain to step the chain up in increments. This prevented the forces of over-shifting to occur. This greatly reduces the energy necessary to shift and the force against the idler pully.

    There is almost no force on the idler pulley to downshift beyond pulling the chain over far enough to be caught on the cog teeth.
     
  16. Froze

    Froze Well-Known Member

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    Tom: Gee, that's weird about the rims wearing out in a year you mentioned. I use to do a lot of riding/training/racing in the mountains of S Calif back between the mid 70's till the mid 80's,. using only high friction pads made by Mathauser and the salmon ones were the most highest friction they had, (I actually ran on Suntour Superbe pads, but those were relabeled Mathauser's, today they're made by Kool Stop) and I would get about 30,000 to 35,000 miles on a rim which was about average for not only my team but other teams I knew as well, and these were lightweight racing rims. So Tom are you saying that today's Campy or Fulcrum rims aren't as good as those from back when I was racing? I have about 16,000 miles on my weekend main bike wheels and they're still good to go for a long time...but those don't see mountains either. I know a guy who does loaded touring all year round, which means wintery stuff (personally I think he's nuts to be touring in wintery stuff but that's just me!), but with rain, snow, salt and dirt all grinding away on his wheels he gets about 3 years on his rims, I haven't had a chance to ask him how many miles he rides in 3 years but I would assume somewhere between 8,000 to 12,000 miles.

    Of course it helps to prolong the life of aluminum wheels by making sure the rim is clean, the pads are cleaned and free of any particles embedded in the pads. This is something we did on our team all the time, but that was because we paid for all our own gear so we did what we could to get stuff to last.
     
  17. cyclintom

    cyclintom Well-Known Member

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    Well, there you go. Froze rode heavyweight wheels with hard aluminum rims back in the 1980's and he can easily tell us that he knows all about the wear markers of a set of super-lightweight aluminum wheels from today. Another mark of the great knowledge and ability to think of his somewhat addled generation.
     
  18. Froze

    Froze Well-Known Member

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    Yeah that's right dumb ass, I use to race cat 3 races on wheels that weighed a 100 pounds each, what a freaking moron you are. And those rims you claim you have, you don't have, and I'm still not going to tell you how I know, but others reading your posts will know how I know!
     
  19. cyclintom

    cyclintom Well-Known Member

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  20. Froze

    Froze Well-Known Member

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    CyclingTom, the definition of insanity according to Einstein is doing the same thing over and over and expecting different results, and this is what I was doing with you, hoping you would see your ignorance and change and it's not working. So to prevent the insanity from just going on and on and getting nowhere with you I have decided to leave the forum. You can take that for a victory for you if so desire because I don't really care anymore about you or your 4 year old behavior, but it's actually a victory for me because I don't have to do that insanity thing over and over with a 4 year old adult. Maybe with some luck everyone on this forum will leave or fail to respond to you, and then you'll only have yourself and your other personalities in your head to talk to.

    Goodbye Tom, and goodbye Cycling Forums that use to be a great forum till Cyclintom showed up.
     
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