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#51
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Deep Freud Moors:
Jose Rizal wrote in message news ![]() Deep Freud Moors: Jose Rizal wrote in message link.net... Deep Freud Moors: With regards to your bearings, if they are well packed with grease, getting water in should not be a big problem. The primary purpose of the grease is not lubrication, but to keep dirt and water out. Not true. In bearings the primary purpose of grease is lubrication. The primary purpose of seals is keeping water and dirt out. Yes true. Grease is grease, and not designed as a lubricant. Oil is designed as a lubricant, grease is not. It does treat the metal surfaces to a degree, but any lubricating effect disappears quickly. And where did you get this little gem of a myth from? You may think you have a new contrary insight into something that's been established by tribology science hundreds of years ago, but I think you're just making it up. Read any basic tribology book. You were the one that claimed it to not be true. Provide a couple of cites, and I might just come around to your view. For the principle behind grease lubrication, type "tribology" on Amazon.com, and you'll get many references. Pick up ANY book on tribology from your nearest tertiary institution library. For evidence of grease as good lubricant, talk to any engineer or engineering student. Talk to any mechanic. In fact, talk to anyone who's ever used grease as lubricant. I'm not going to do the work for you. Your claim that grease does not lubricate is what's ridiculously false. When you pack your bearings with grease, it gets pushed out of the way of the bearings after a couple of turns, and does not return due to its viscosity. So why do you think your bearings remain lubricated when only grease is ever applied by the manufacturer/mechanic? Grease consists of oil and carrier compound. The carrier is thick and while the bulk of it may be pushed out of the way of the bearing/race interface, the oil remains between the contact patch and the carrier/oil compound which stays around the path ensures a steady supply of lubricant. That is what I would constitute as "treating" the metal surface. You meant nothing of the sort and you know it. You're wrong in any case. "Treating the metal surface" implies changing the property of the metal, such as anodizing or any process that alters the structure of the metal. Applying oil or grease does not "treat" the metal because it does not change its basic structure. You have not answered the question: why do bearings remain lubricated when grease is applied, when according to your theory, the grease will be pushed out by the bearings? The driest part of the bearing assembly is usually the surface where the bearings run. Please. The bearing/race contact path is not in fact dry, but lubricated with a thin film provided by the grease. Even with a tremendous load the film remains; the only way to eliminate the lubricant is to wash it away with solvent or stop replenishing it, in which case it may dry up eventually. Grease ensures adequate lubricant supply for a longer time than mere oil. I said "driest". I did not say dry. Semantics do not provide you with any refuge. The greased bearing/race interface isn't "dry", "drier", or "driest". Oil exists between the interface even when loaded to such an extent that the race surface is deformed. Yes the grease treats the metal causing it to last longer. No, grease does not treat the metal, it provides lubrication. Lubrication lasts longer when using grease because the oil carrier that sticks around keeps an oil supply to the interface, which would otherwise just run off. Whether or not this constitutes "lubrication" is up for debate, but bugger all of the grease hangs around the bearing contact surfaces. It's not up for debate, grease provides lubrication for the metal contact areas in greased systems. It's obvious you know nothing about basic tribology, so brush up on the basics before you spout myths about lubrication. Whilst that surface is clean, there are no probs. Basic wheels nowadays are not sealed either, but have donut-shaped little caps, which are designed to work in conjunction with the grease to keep dirt and water out. Grease as water and dirt barrier is a secondary characteristic, not primary. Utter bull****. Dirt will kill bearings MUCH faster than an absence of grease. Clean dry bearings will run for a long time, dirty bearings (even when greased) will not. Don't change the subject. Grease's secondary property as water and dirt barrier is what's been pointed out, NOT whether dirt is destructive to bearings. Grease in fact attracts dirt. It's not a substitute for seals. If it were so, seals for bearings or any rotating machinery will not be necessary. That is why both seals and grease are used. Stop making things up. If you have references to your dubious claims, provide them. On the other hand, it's quite easy to check the falsity of your claims from a multitude of easily accessible resources. |
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#52
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Deep Freud Moors:
Jose Rizal wrote in message news ![]() Deep Freud Moors: Jose Rizal wrote in message link.net... Deep Freud Moors: With regards to your bearings, if they are well packed with grease, getting water in should not be a big problem. The primary purpose of the grease is not lubrication, but to keep dirt and water out. Not true. In bearings the primary purpose of grease is lubrication. The primary purpose of seals is keeping water and dirt out. Yes true. Grease is grease, and not designed as a lubricant. Oil is designed as a lubricant, grease is not. It does treat the metal surfaces to a degree, but any lubricating effect disappears quickly. And where did you get this little gem of a myth from? You may think you have a new contrary insight into something that's been established by tribology science hundreds of years ago, but I think you're just making it up. Read any basic tribology book. You were the one that claimed it to not be true. Provide a couple of cites, and I might just come around to your view. For the principle behind grease lubrication, type "tribology" on Amazon.com, and you'll get many references. Pick up ANY book on tribology from your nearest tertiary institution library. For evidence of grease as good lubricant, talk to any engineer or engineering student. Talk to any mechanic. In fact, talk to anyone who's ever used grease as lubricant. I'm not going to do the work for you. Your claim that grease does not lubricate is what's ridiculously false. When you pack your bearings with grease, it gets pushed out of the way of the bearings after a couple of turns, and does not return due to its viscosity. So why do you think your bearings remain lubricated when only grease is ever applied by the manufacturer/mechanic? Grease consists of oil and carrier compound. The carrier is thick and while the bulk of it may be pushed out of the way of the bearing/race interface, the oil remains between the contact patch and the carrier/oil compound which stays around the path ensures a steady supply of lubricant. That is what I would constitute as "treating" the metal surface. You meant nothing of the sort and you know it. You're wrong in any case. "Treating the metal surface" implies changing the property of the metal, such as anodizing or any process that alters the structure of the metal. Applying oil or grease does not "treat" the metal because it does not change its basic structure. You have not answered the question: why do bearings remain lubricated when grease is applied, when according to your theory, the grease will be pushed out by the bearings? The driest part of the bearing assembly is usually the surface where the bearings run. Please. The bearing/race contact path is not in fact dry, but lubricated with a thin film provided by the grease. Even with a tremendous load the film remains; the only way to eliminate the lubricant is to wash it away with solvent or stop replenishing it, in which case it may dry up eventually. Grease ensures adequate lubricant supply for a longer time than mere oil. I said "driest". I did not say dry. Semantics do not provide you with any refuge. The greased bearing/race interface isn't "dry", "drier", or "driest". Oil exists between the interface even when loaded to such an extent that the race surface is deformed. Yes the grease treats the metal causing it to last longer. No, grease does not treat the metal, it provides lubrication. Lubrication lasts longer when using grease because the oil carrier that sticks around keeps an oil supply to the interface, which would otherwise just run off. Whether or not this constitutes "lubrication" is up for debate, but bugger all of the grease hangs around the bearing contact surfaces. It's not up for debate, grease provides lubrication for the metal contact areas in greased systems. It's obvious you know nothing about basic tribology, so brush up on the basics before you spout myths about lubrication. Whilst that surface is clean, there are no probs. Basic wheels nowadays are not sealed either, but have donut-shaped little caps, which are designed to work in conjunction with the grease to keep dirt and water out. Grease as water and dirt barrier is a secondary characteristic, not primary. Utter bull****. Dirt will kill bearings MUCH faster than an absence of grease. Clean dry bearings will run for a long time, dirty bearings (even when greased) will not. Don't change the subject. Grease's secondary property as water and dirt barrier is what's been pointed out, NOT whether dirt is destructive to bearings. Grease in fact attracts dirt. It's not a substitute for seals. If it were so, seals for bearings or any rotating machinery will not be necessary. That is why both seals and grease are used. Stop making things up. If you have references to your dubious claims, provide them. On the other hand, it's quite easy to check the falsity of your claims from a multitude of easily accessible resources. |
#53
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Mike:
OK guys, grease is definitely a lubricant, but what exactly is its effect in a bike wheel hub? Grease is basically a source of oil for the lubricated system. It is made up essentially of two compounds, oil and thickener (or carrier). Either or both can have additives. The carrier carries the oil and releases it at the appropriate occassion, when the bond between the oil and carrier is broken. This occurs at particular temperatures and/or pressures. The carrier can also act as a lubricant by sticking to the surfaces of the contacting elements. This carrier film eventually wears away and must be replenished, either by more oil or more carrier. Since grease (ie both carrier and oil) doesn't flow readily, most of the lubrication is accomplished by the oil that is released from the carrier. |
#54
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Mike:
OK guys, grease is definitely a lubricant, but what exactly is its effect in a bike wheel hub? Grease is basically a source of oil for the lubricated system. It is made up essentially of two compounds, oil and thickener (or carrier). Either or both can have additives. The carrier carries the oil and releases it at the appropriate occassion, when the bond between the oil and carrier is broken. This occurs at particular temperatures and/or pressures. The carrier can also act as a lubricant by sticking to the surfaces of the contacting elements. This carrier film eventually wears away and must be replenished, either by more oil or more carrier. Since grease (ie both carrier and oil) doesn't flow readily, most of the lubrication is accomplished by the oil that is released from the carrier. |
#55
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"Deep Freud Moors" wrote
Yes true. Grease is grease, and not designed as a lubricant. Oil is designed as a lubricant, grease is not. It does treat the metal surfaces to a degree, but any lubricating effect disappears quickly. When you pack your bearings with grease, it gets pushed out of the way of the bearings after a couple of turns, and does not return due to its viscosity. The driest part of the bearing assembly is usually the surface where the bearings run. Whilst that surface is clean, there are no probs. Basic wheels nowadays are not sealed either, but have donut-shaped little caps, which are designed to work in conjunction with the grease to keep dirt and water out. What the? Why the hell do they grease wheel bearings in cars then? Theo |
#56
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"Deep Freud Moors" wrote
Yes true. Grease is grease, and not designed as a lubricant. Oil is designed as a lubricant, grease is not. It does treat the metal surfaces to a degree, but any lubricating effect disappears quickly. When you pack your bearings with grease, it gets pushed out of the way of the bearings after a couple of turns, and does not return due to its viscosity. The driest part of the bearing assembly is usually the surface where the bearings run. Whilst that surface is clean, there are no probs. Basic wheels nowadays are not sealed either, but have donut-shaped little caps, which are designed to work in conjunction with the grease to keep dirt and water out. What the? Why the hell do they grease wheel bearings in cars then? Theo |
#57
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Theo Bekkers wrote in message
... "Deep Freud Moors" wrote Yes true. Grease is grease, and not designed as a lubricant. Oil is designed as a lubricant, grease is not. It does treat the metal surfaces to a degree, but any lubricating effect disappears quickly. When you pack your bearings with grease, it gets pushed out of the way of the bearings after a couple of turns, and does not return due to its viscosity. The driest part of the bearing assembly is usually the surface where the bearings run. Whilst that surface is clean, there are no probs. Basic wheels nowadays are not sealed either, but have donut-shaped little caps, which are designed to work in conjunction with the grease to keep dirt and water out. What the? Why the hell do they grease wheel bearings in cars then? Exactly the same reason of course. --- DFM |
#58
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Theo Bekkers wrote in message
... "Deep Freud Moors" wrote Yes true. Grease is grease, and not designed as a lubricant. Oil is designed as a lubricant, grease is not. It does treat the metal surfaces to a degree, but any lubricating effect disappears quickly. When you pack your bearings with grease, it gets pushed out of the way of the bearings after a couple of turns, and does not return due to its viscosity. The driest part of the bearing assembly is usually the surface where the bearings run. Whilst that surface is clean, there are no probs. Basic wheels nowadays are not sealed either, but have donut-shaped little caps, which are designed to work in conjunction with the grease to keep dirt and water out. What the? Why the hell do they grease wheel bearings in cars then? Exactly the same reason of course. --- DFM |
#59
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On Fri, 03 Oct 2003 14:09:33 GMT, Steve Reynolds
wrote: Want to know how to clean your chain see: http://www.sheldonbrown.com/chains.html Forgot to mention in my last post. The plastic jars that you buy Goulburn Valley fruit from the supermarket in, are far better than the coke bottle that Sheldon mentions in his article. The large diameter lid makes it much easier to retrieve the chain from the jar, far easier than fishing around in the coke bottle trying to hook the chain with an old spoke. 7,000 kilometres on my roadie's SRAM PC89R chain so far, with no measurable wear after maintaining it using a Sheldon's method. SR |
#60
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On Fri, 03 Oct 2003 14:09:33 GMT, Steve Reynolds
wrote: Want to know how to clean your chain see: http://www.sheldonbrown.com/chains.html Forgot to mention in my last post. The plastic jars that you buy Goulburn Valley fruit from the supermarket in, are far better than the coke bottle that Sheldon mentions in his article. The large diameter lid makes it much easier to retrieve the chain from the jar, far easier than fishing around in the coke bottle trying to hook the chain with an old spoke. 7,000 kilometres on my roadie's SRAM PC89R chain so far, with no measurable wear after maintaining it using a Sheldon's method. SR |
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