Sixty Fiver

Ceramic bearings are a waste on a bike.

Most good quality cup and cone systems should be checked and overhauled yearly if the bike is ridden with any regularity, cartridge bearings provide a much longer service interval and I have had our customers call us after 25,000 of km of hard riding to tell me their hubs are still running as smoothly as they did on day 1.

I would avoid any cartridge system where the bearings are proprietary to make replacement easier, whenever that time comes.

wolfchild

I have Surly hubs and Formula hubs with cartridge bearings, they are still perfect after many years of hard use, never had to replace the bearings yet...My Shimano Deore XT's have also been flawless...

Dave Mayer

Campagnolo Record hubs. The 2 cartridges inside the freehub. The biggest challenge was figuring out a way of extracting them from within the freehub. I managed to get them out after several days of effort. The bearings were seized up solid, and the bearing shells were corroded into the freehub shell. So much for the supposed cartridge bearing benefits of resistance against contamination and ease of replacement.

And I did find suitable replacements online, although they will only arrive from China in 6 weeks, due to the port strikes on the W. Coast. Ironic that you mention 300 different cartridge bearing 'standards'. Standards indeed. All of the rear cup 'n cone hubs I've worked on take 1/4" balls, a true standard. And they can be bought for about $5 for a 100.

Go into a bike shop and try to buy replacement catridge bearings? Ha. Good luck with that. Even if they did have a drawer of them, what would be the motivation of the shop to sell these versus an entire wheelset? Particularly when you'll be expected to leave your old wheelset behind for 'disposal'. Out of about a dozen tries, I have never been able to source a single cartridge bearing out of a bike shop, even for the most common the cart in the bike universe: the 6001.

So my replacement bearings will arrive. I have deliverately avoided ceramic bearings, as these are a laughable scam. The difference in drag/friction between these and standard steel are not even measurable. If required in the future, I will repack the bearings with white lithium grease I bought at a yard sale for 25 cents for a one pound tub. Good as anything out there.

bowlofsalad

I think the generalization about bearing maintanence can cause problems. I can't say when is the right time for certain, but yearly is far too vague and general of a statement.

I understand what you are saying, but the variations between levels of drag are really hard to detect without scientific measurement. You may say "Well then, it's good enough, why worry." I am not critically worried about losing a watt or two to drag, but if the lubrication is contaminated and/or the seal is broken, something needs to be fixed. Things will only get worse, not better. I guess what I am saying is that the observations are hearsay and anecdotal. You'll hear the same tales from folks who use cups and cones(CaC) just the same as you will who use cartridges, neither are necessarily going to mean that their ability to maintain clean and dry lubrication is superior, nor is there any correlation between CaC or cartridge bearings and keeping lubrication clean.. What I am hoping to point out is science is good, anecdotal observations isn't science.

I dislike proprietary ideas myself as well, which is why at this point(after decades of cycling) I am almost absolutely unwilling to purchase any more CaC hubs. SKF, *** and plenty of other bearing manufacturers will extremely likely continue to make whatever cartridge bearing size you need for your hub for as long as you are alive and beyond. I think a lot of people are stuck on CaC bearings relating to unwillingness to change and the idea that cup and cone offer slightly less drag compared to cartridge bearings. True or not, the benefit to drag for CaC isn't worth it to me, but I am not trying to win any races. The races and whatever seal/shield comes with the a CaC hub are the ones you are stuck with for as long as you use that hub, this isn't so with cartridge bearings, that alone makes cartridges a winner for options.

Ball bearings are only one part of a hub, the inner and outer races are proprietary components in all (CaC) hubs, and the cups are non-replaceable in nearly all CaC hubs. It's very likely that if you needed to replace the ball bearings, you needed to replace both the inner and outer races as well, the bearings themselves aren't the only thing that begins accumulating damaged when the lubrication gets dirty. You may be able to acquire loose ball bearings some places, but spare cones? Some CaC hubs no longer have replacement cones made for them anywhere by anyone, not to mention availability being equally as hard as what you described.

It's misinformation to state that one type of lubrication is good for all applications. There is much more to choosing grease that is suitable for a specific application, much more. I am not saying your lubrication couldn't possibly be suitable or work out ok, but it surely wouldn't be 'good as anything out there'. Step-by-Step Grease Selection I implore you to read this article, it won't just dispel any mysticism about lubrication, but it may aid you in choosing a lubrication that is more suitable to your needs.

Do you have any specific sources of information or articles on the statements you make about teflon powder? Why would I want to use teflon instead of grease/oil?

Sealed bearings, all that I am familiar with, use rubber, not plastic, seals. But in any case that I am familiar with, contact seals -require- lubrication, it isn't optional, it is essential. If the seals aren't lubricated, they will burn away and the powder you suggest using will surely blow out quickly without a seal, or the lubrication inside with much more easily become contaminated or even leak out.

The principle behind using oil (grease is oil with substances added to increase stiffness) for lubrication involves hydrodynamic lubrication. https://www.youtube.com/watch?v=mK-iz_xfEI4 This idea is very important. I am interested but extremely skeptical that using teflon powder alone is superior to hydrodynamic lubrication. I hope you have serious sources to back up your claims. An important note, teflon isn't good for your health, it's actually extremely bad for you, teflon powder isn't something that should be handle casually, especially in powder form, yikes.

You are mistaken about the outer diameter being the only important piece of information. All of the dimensions are important, I don't know why you made this claim, but I strongly disadvise this course of action. I suspect you don't understand how bearings work or what the function of the inner and outer races are. You aren't going to get a matched size cartridge bearing just from the outer dimension alone.

cyccommute 

"Hard" what? Your sentence is incomplete.

Even with scientific measurement the levels of drag are hard to detect. That means, generally, that the differences in drag due to bearings and lubrication is trivial and (mostly) unimportant. As cyclists, the load is too small and the speeds are too low to make any real difference. I would suspect that the effect of lubrication is so small that if you removed the lubrication entirely, you couldn't measure any effect at all. Even damage to the parts isn't going to happen immediately but, instead, will take many miles (on the order of 100s or 1000s) to manifest itself

You also can't really predict what will happen if the lubricant is contaminated without knowledge of the contaminants. If the lubrication is contaminated with water, the water is still a lubricant and likely won't do anything to damage parts except over the very long haul. Contamination from "dirt" would also be hard to predict. Sand contamination, i.e. silicon dioxide, will damage parts the quickest because the sand is harder than the steel. But if you were to have clay in the lubricant, it behaves differently and might not cause damage at all.

Science isn't devoid of observation. It's as important a part of the scientific process as data. Most of the time, observation is where science starts. You observe something that is unexpected and you collect data to explain what is observed. You can't have data without observation and you can't make sense of the data without observation.

While the grease selection guide is good, we bicyclists fall off the end of the chart. If you look at Figure 1 in that link, bicycles operate at around 20°C and at low RPM. We are below the bottom of that chart. We are operate at a point where just about any lubricant probably has too high a viscosity for our application but the problem is keeping the lubrication in place if it is thin enough to work for the loads we put on it. Bottom line: which lubricant you choose for a bicycle application doesn't matter.


Well, technically, "rubber" is a plastic in that it belongs to a large class of chemical compounds called polymers. Some polymers are harder...usually called "plastic"...while some are softer and are called elastomers. The seals on a cartridge bearings aren't really "rubber" either. "Rubbers" is polyisoprene. Most of the contact seals I've seen on cartridge bearings are not an elastomer but a harder plastic...likely polyethylene or polypropylene or some co-polymer using those components. Doug5150's point was to use bearings with polymer seals rather than metal seals.

A dry seal on a bicycle bearing wouldn't necessarily "burn away". There's not the much friction in the system.

I don't really care about using teflon as a lubricant...there are better choices out there...but "teflon" isn't bad for your health. Teflon is inert. That is the reason that it is used for all kinds of applications. It doesn't react with anything. You could eat handfuls of the stuff everyday and all it would do is pass through your system. You can deep fry it and eat it with your fries and not have problems.

Above 250°C, the polymer starts to decompose (teflon doesn't melt) into some very nasty compounds but below that temperature, it is entirely safe to use in any form.

You seem to misunderstand what Doug5150 is saying. He's not saying that the outer dimension is the only important piece of information only that those dimensions are needed for replacements...which is correct.

bowlofsalad

Allow me to illustrate, if you picked up a grease that was meant for a much higher or lower temperature scenario that with much greater loads and RPMs or some combination of the three, you'll likely end up with a less than ideal grease. There is a wildly larger range of greases in existence, they are not all the same. All greases are not suitable for all applications, including in bicycles.

I think you misunderstand my statement and are trying to twist it into something other than what it is. Anecdotal observations aren't scientific observations. I am not discounting the idea of observation itself, there is more to the context of an observation than having eyeballs. A scientific observation involves radically higher accuracy, controlled variables and much closer attention than "The wheel, she spins reel gewd man." Anecdotal observations are very casual, mild, unscientific, worthless to make statements on of much substance. So when someone says "I haven't even looked at my lubrication in 10,000 miles because the wheel spins good." that doesn't mean anything worth stating, it simply means that they are ignorant of what is really happening and have no idea of the state of their lubrication and no way to detect any damage to the bearings/race. Once your lubrication is contaminated, the damage only gets worse, and at a self increasing rate. Yes there are variables, but my statement still holds validity.

There is an idea known as confirmation bias. https://www.youtube.com/watch?v=6xMaR8au-YU This is a universally important idea that is very much worth looking into and I highly recommend studying confirmation bias.

Try to imagine getting teflon powder in your lungs. It wouldn't be good for you, I promise. No need to mess around with materials handling safety.

I guess all I can say is you are mistaken, and this would be a very poor and pointless mistake to make. I don't think you understand what friction is or how it applies to the contact points of the seals themselves. Lubrication creates a hydrodynamic film that inhibits a lot of friction, two opposing surfaces surf against the pressure each generate as they move on the surfaces of oil. Imagine a surfboard gleaming across the surface of an ocean, then dragging it behind a car on a concrete road, this is much of what the difference is between lubrication and no lubrication, many variables here but the simple way of understanding this concept. The surfboard will be damaged and destroyed without the ocean much like the seal will be without lubrication.

To further help you gain understanding on this, go get an eraser and rub a corner of it on something that is dry for a little while. Now put a drop of soap or oil on that same spot and rub it around with the same force you used before. Learning is fun.

"Normally you can just measure the outer dimensions of bearings and replace them with any that are the same type & dimensions. Sometimes they have a custom ID number on them, but that isn't important. The outer dimensions is all you really need to match." Re-read this statement, it's a bad one to make. https://www.youtube.com/watch?v=WLx3ov6jvik Watch this video to learn more about bearing dimensions.

Lets remember folks, the threads topic is keeping lubrication clean and dry longer. We need more science!

https://www.skf.com/binary/83-179206/...ls_6270-EN.pdf On page 6 there is a chart that shows a simple version in comparing various cartridge bearing cover characteristics. Interesting stuff.

JanMM

At 10,000 miles if it spins good and turns smoothly in my fingertips, I'm ok with being igorant [sic].

Doug5150

This wikipedia article has a chart that shows that the coefficient of friction between teflon-on-teflon (dry) is one-fourth that of lubricated steel on steel. Friction - Wikipedia, the free encyclopedia

Because Teflon is the lowest-friction material that you can easily obtain. IIRC there is two or three other substances that are more-slippery now, and all are still laboratory curiosities. BAM is one of them: Material slicker than Teflon discovered by accident - tech - 21 November 2008 - New Scientist

Grease--by the by--is an oil, with a solid thickener added. The thickener does not lubricate.
When grease "cakes up", what happened was the oil ran out leaving behind the thickener behind. That happens with all greases. That is something that can't happen with Teflon powder, because there's never any liquid in the first place. In fact, Teflon powder repels liquids.

Well now, rubber is a polymer, is it not? (and full-ceramic bearings do sometimes have teflon seals in them)
And you can wipe some powder around the inside hole as you're putting them back on. Teflon is safe to use on anything, since it doesn't dissolve or degrade any other materials.

The LD50 for pure Teflon has never been conclusively found, it has only been estimated. And that figure is a mind-boggling > 11,280 mg/kg in rats; it is one of the highest LD50 levels assigned for anything.
Just for fun, go look up the LD50 of the lubricant you use in bearings or on your chain.....

The only risks that the MSDS sheets give for Teflon is A) inhaling the dust, B) getting the dust in your eyes or C) inhaling the burned compounds. And the MSDS sheet for EVERYTHING solid says A and B.

No, I said to "measure the outer dimensions". All three of them. The outer diameter, inner diameter and width. And then go find bearings of the same type that match all three measurements.

Doug5150

Yea but no.
Teflon moving against Teflon (like, in a volume of Teflon powder) has LOWER friction than two lubricated steel parts sliding across each other. Even dry, the Teflon is still less friction.

Yea but no again.
Among standard sizes, bearings that are different internally are also made different externally, precisely so that they cannot ever be confused in use.

For example, consider these skate bearings (these are real actual sizes):

A 608 bearing measures 8mm ID x 22mm OD x 7mm wide
A 627 bearing measures 7mm ID x 22mm OD x 7mm wide
A 688 bearing measures 8mm ID x 16mm OD x 4mm wide
A 698 bearing measures 8mm ID x 19mm OD x 6mm wide

All four of those bearings have different ID numbers, and all four of them have different physical dimensions as well. You can't fit the 'wrong' bearing into the place of any other.
You're never going to find a #608 bearing that measures the same as a #698 .
So it is pretty safe to just measure the old ones, and buy new ones the same size.

cyccommute 

Then don't pick up a grease that is formulated for much higher or much lower temperatures. It's that simple. However, when using a general purpose grease, the range of operating temperatures and the loads are very broad and most anything you can get at a general auto parts or bicycle shop is going to serve the purpose.

You are over thinking this.

You are the one who is twisting. Scientific observation involves measuring. But sometimes you can't control everything and have to just allow for variables over which you have no control. Part of the problem with what you are asking is that there isn't a good way of measure what you want to measure. Wheel Energy tried and there was too much variability in their equipment to get any meaningful results. In other words, they couldn't measure any differences between various bearings and treatments. If you know a way to measure the energy required or how much damage has been done to bearings, feel free to design a way to measure it. It's not all that easy.

As for the statement "I haven't even looked at my lubrication in 10,000 miles because the wheel spins good," you might be able to discount it. But there might be something there as well. Don't discount it just because it conforms to you own confirmational biases. And, contamination doesn't matter for a cartridge bearing because when you damage the bearing, you replace it. It matters more for cup and cone but that is why you should rebuild cup and cone bearings on a regular basis.

You weren't talking about breathing it and made this blanket statement about teflon.

But teflon is not hazardous to your health. It's certainly not "extremely" bad for you...even in dust form. Teflon dust is going to be the least hazardous of thousands of substances that you could inhale on a daily basis...mostly because you are more likely to run across those substances on a daily basis and only rarely run across teflon. Right now you have more silica dust in your lungs than teflon dust.

As silly as your analogy is, the surfboard wouldn't be "burned" way. Your term, not mine. "Burning" a seal away implies something different from "wearing" a seal away. "Burning" implies a higher heat load. The teflon will also lubricate the seals like an oil will. Teflon is a nearly frictionless material and might even be lower than the grease it replaces.

Now you are just being a condescending ass. But I'll play along, do the same experiment but put teflon on the eraser. The friction will actually be less because the teflon will ride on the surface and not be absorbed into the fabric of the eraser. Teflon is a dry lubricant, after all.

Yes, isn't learning fun?

You keep asking for "science" but haven't volunteered any of your own yet. Go look up stuff on your own or, if you can't find it, sink a few hundred thousand dollars into designing your own test beds. We'll wait for results.

A bit dry but whatever floats your boat. On greases, however, here is what they say:

so order up any grease you like but be aware that the temperature ranges are all much the same.

Even the "high" temperature grease is only 40°C higher operating temperature than the standard grease. That's not much. These bearings are also designed for heavier duty than we bicycles can ever put them through. Basically, it doesn't matter.

cyccommute 

With an LD50 that high, they probably killed the slow half of the population. The ones that just couldn't get out of the way when they dropped the teflon on them

bowlofsalad

While this is interesting, I am still skeptical. Lubrication tips for plastic gears and more | Mechanical Drives content from Machine Design This article writes a bit about this subject, mentioning gears made out of teflon. https://machinedesign.com/site-files/...s-friction.jpg The lubrication added decreases friction, so perhaps teflon alone isn't the best lubrication. To add to this, I don't know if I would count on it alone to making it a perfect way to lubricate a seal. The idea sounds intruiging, but perhaps a little synthetic automatic transmission fluid tossed in with the teflon would be better.

My vague understanding is oil separating from thickeners primarily relates to aging and temperature, but the oil from the grease is still retained assuming you have a functioning seal. I have had intentions of performing an idea very similar to what you mentioned, but instead of using teflon, I would use an ideal oil with some very strong seals. Do you have any other articles on this subject relating to teflon replacing oil as lubrication? Friction and Coefficients of Friction This is the article that is linked to, I'd like to know more on this subject. Know of any other articles specific to this subject? Have you ever attempted this idea yourself?

I have seen and read about secondary teflon seals, but that doesn't convince me entirely that teflon alone is the way to go for lubrication, nor is it really the answer to the question this thread is based around. What can we do to keep the lubrication uncontaminated longest? Am I correct when I say dirt and water may still come in contact with a bearing and it's races even where there is teflon involved?

The ideas presented for using teflon almost sound revolutionary, but I have a healthy skepticism about it and various searches aren't turning up much I can use to explore with.

Thanks for the response!

I feel it is necessary to say that when I write these words, I do not write them with any hint of emotion, malice, hate or pride. There is no need to project an attitude into these words.

cyccommute 

Looking at the figure, you can see that the friction of a steel on teflon surface is relatively low. According the The Engineer's Toolbox the wetted friction is on the same order as a wetted steel on steel surface. The Toolbox lists dry steel on teflon as ranging from 0.04 to 0.2µ. Wetting the surface of the teflon brings the coefficient down to the lowest end of the scale.

Water, by the way, would probably have the same effect as oil in your link. As Doug5150 says, Teflon repels all liquids. At some point, the viscosity of the liquid used will start to cause drag. Oil probably isn't the best choice because its viscosity is high. If you wanted the lowest possible friction, water (viscosity = 1cps) would be a very good choice. Acetone (0.4 cps) would be even better. The problem would be keeping it in place. The seals needed would have to be much better than those for oils.

The seals are going to be the problem. That's one of the reasons you need to refresh the grease in cup and cone hubs more often. The seals aren't all that efficient and allow some of the oil in the grease to get past the seal. They also allow contaminates to flow the other direction. The seals used in the cartridge bearing used in bicycle hubs...no matter what many will tell you...are much better than the simple contact seals used in cup and cone hubs. They keep the oil inside better and thus don't need to be regreased.

But there are limits to what the seals will hold and for how long. You could remove all the grease from a cartridge bearing and replace it will a light oil but it will seep out quickly. I don't think anyone makes a seal for that kind of bearing that would contain just a fluid for long. The seals will keep water out but that's partly due to the seal and the grease packed in the bearing. Keeping a low viscosity fluid in would be more problematic.

Teflon powder wouldn't be a bad place to start for something that is easy to keep in place and it won't flow out. The problem is that it doesn't flow as easily as liquid. Perhaps at a nanometer scale it would but that would be hard to predict.

I would say that getting water and dirt into the bearings would depend on the seal. If you are talking about a modern cup and cone hub with good seals, you might get some water and/or dirt in them but it would be difficult. Old hubs with dust seals are like screen doors on a submarine. Cartridge bearings with polymer seals are going to keep the crap out the longest and the best.

I have no idea how old you are but back in my youth, we changed the oil in our vehicles every 3000 miles and we greased the front suspension and steering on our vehicles. If you were really OCD about it, you repacked the front hub bearings about yearly. The bearings on the steering were unsealed and the grease is what kept the crap that you throw at the underside of the car from getting into the bearings. Somewhere around the mid80s cars started showing up without zerks because they were starting to use sealed cartridge bearings. Cars now don't have any way to grease the steering and suspension. They don't need to.

Those same sealed bearings are used in bicycle hubs and if they can go for 200,000+ miles under the kinds of stress that a car can put on them, how far do you think they can go in the light duty of a bicycle?

Sixty Fiver

I was not generalizing... bearing service is a function of mileage, bearing type, and individual riding conditions.

If you ride your bicycle on a regular basis then it is a good idea to service it yearly (like in the spring), my winter bicycles with cup and cone bearings get more regular service because of the harsher riding conditions. With that, the rear hub on my primary winter bike is a Shimano 105 and it looks to have outlasted the rear wheel which I now need to look at replacing because of wear. The wheel has 25,000 + km on it and has seen some harsh conditions but the hub is still in excellent condition.

Super high mileage riders should observe a higher maintenance schedule.

Even if no service is needed it is a good preventative measure and one can then check that the bearings are also set properly... the average mileage of most cyclists is low enough that they could probably go years if they never rode in bad weather and had decent quality hubs that were properly set up.

The cartridge bearings wheels just keep going and going and even the messengers I know and work with have trouble killing them and they ride more and ride more in bad weather than most.

It is pretty simple really.