#11
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Sealed Bearings
"John B." wrote in message ... On Tue, 31 May 2016 21:38:48 +0100, "Ian Field" wrote: wrote in message ... With all the bikes I have I also have a bike for which I built the wheels on old Campy record hub on the back and DuraAce on the front. After getting this bike back from a friend who was saving it for me while I was not in the best of health I rebuilt the wheels with new balls and Campy grease. I have mostly modern wheelsets from Campy or Fulcrum (the people who make the modern Campy hubs etc.) These wheels have sealed bearings. These sort of bothered me when I saw them because of the drag of the seals. You can tell simply spinning the wheels in a stand. But I imagined that with the weight of a person this would be insignificant. For the last couple of days I have been riding the old Look and in fact you CAN feel the difference between the open bearings and the sealed. It does coast much further and with less noise. If you mean regular bearings like the ones used for gear box shafts; there's a choice between shielded and oil seal bearings. The oil seal type have noticeable friction, while AFAIK: the shielded type just have a stainless steel shield that doesn't have any actual contact with the inner ring. The oil seal type are only unavoidable if you need to contain oil. The shielded type are OK with grease, but not 100% at keeping road grit out. You over simplify, There are basically three types of cartridge bearing. Plain (open, no seals or shields), Shielded and Sealed. Evidently not simple enough for you - the discussion was not about open bearings. |
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#12
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Sealed Bearings
On Wed, 1 Jun 2016 18:39:42 +0100, "Ian Field"
wrote: "John B." wrote in message .. . On Tue, 31 May 2016 21:38:48 +0100, "Ian Field" wrote: wrote in message ... With all the bikes I have I also have a bike for which I built the wheels on old Campy record hub on the back and DuraAce on the front. After getting this bike back from a friend who was saving it for me while I was not in the best of health I rebuilt the wheels with new balls and Campy grease. I have mostly modern wheelsets from Campy or Fulcrum (the people who make the modern Campy hubs etc.) These wheels have sealed bearings. These sort of bothered me when I saw them because of the drag of the seals. You can tell simply spinning the wheels in a stand. But I imagined that with the weight of a person this would be insignificant. For the last couple of days I have been riding the old Look and in fact you CAN feel the difference between the open bearings and the sealed. It does coast much further and with less noise. If you mean regular bearings like the ones used for gear box shafts; there's a choice between shielded and oil seal bearings. The oil seal type have noticeable friction, while AFAIK: the shielded type just have a stainless steel shield that doesn't have any actual contact with the inner ring. The oil seal type are only unavoidable if you need to contain oil. The shielded type are OK with grease, but not 100% at keeping road grit out. You over simplify, There are basically three types of cartridge bearing. Plain (open, no seals or shields), Shielded and Sealed. Evidently not simple enough for you - the discussion was not about open bearings. No it wasn't, but then, you are so accustomed to shouting "****wit" I thought it best to be overly cautious and cover all possible points of contention, as it is obvious from the "Great V-brake Discussion" that your mechanical abilities is, well, rather limited. Obviously it was a mistake as you still shout and scream. -- cheers, John B. |
#14
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Sealed Bearings
"John B." wrote in message ... On Wed, 1 Jun 2016 18:39:42 +0100, "Ian Field" wrote: "John B." wrote in message . .. On Tue, 31 May 2016 21:38:48 +0100, "Ian Field" wrote: wrote in message ... With all the bikes I have I also have a bike for which I built the wheels on old Campy record hub on the back and DuraAce on the front. After getting this bike back from a friend who was saving it for me while I was not in the best of health I rebuilt the wheels with new balls and Campy grease. I have mostly modern wheelsets from Campy or Fulcrum (the people who make the modern Campy hubs etc.) These wheels have sealed bearings. These sort of bothered me when I saw them because of the drag of the seals. You can tell simply spinning the wheels in a stand. But I imagined that with the weight of a person this would be insignificant. For the last couple of days I have been riding the old Look and in fact you CAN feel the difference between the open bearings and the sealed. It does coast much further and with less noise. If you mean regular bearings like the ones used for gear box shafts; there's a choice between shielded and oil seal bearings. The oil seal type have noticeable friction, while AFAIK: the shielded type just have a stainless steel shield that doesn't have any actual contact with the inner ring. The oil seal type are only unavoidable if you need to contain oil. The shielded type are OK with grease, but not 100% at keeping road grit out. You over simplify, There are basically three types of cartridge bearing. Plain (open, no seals or shields), Shielded and Sealed. Evidently not simple enough for you - the discussion was not about open bearings. No it wasn't, but then, you are so accustomed to shouting "****wit" I thought it best to be overly cautious and cover all possible points of contention, as it is obvious from the "Great V-brake Discussion" that your mechanical abilities is, well, rather limited. Obviously it was a mistake as you still shout and scream. You're the one that keeps on ranting - and I've seen at least one other person on the receiving end. |
#15
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Sealed Bearings
On 6/2/2016 12:40 PM, Joerg wrote:
On 2016-06-01 17:55, Phil W Lee wrote: Joerg considered Wed, 01 Jun 2016 10:02:11 -0700 the perfect time to write: On 2016-05-29 20:03, Frank Krygowski wrote: On 5/29/2016 2:40 PM, wrote: With all the bikes I have I also have a bike for which I built the wheels on old Campy record hub on the back and DuraAce on the front. After getting this bike back from a friend who was saving it for me while I was not in the best of health I rebuilt the wheels with new balls and Campy grease. I have mostly modern wheelsets from Campy or Fulcrum (the people who make the modern Campy hubs etc.) These wheels have sealed bearings. These sort of bothered me when I saw them because of the drag of the seals. You can tell simply spinning the wheels in a stand. But I imagined that with the weight of a person this would be insignificant. For the last couple of days I have been riding the old Look and in fact you CAN feel the difference between the open bearings and the sealed. It does coast much further and with less noise. Has anyone else noticed this? FWIW, of my four most-ridden bikes, two have sealed bearing hubs and two do not. I can't tell the difference in the hubs. Perhaps it's because the bikes are quite different; but even on the workstand, I haven't noticed any difference. No wonder. Just imagine what would happen if only 2% of a sporty rider's 200W would be lost in the bearings. That would come to 1W dissipation per bearing and they'd become very toasty. Yet they never do. I think you'll find that a typical aluminium bicycle wheel hub will VERY easily dissipate quite a few watts - probably well into double digits - without getting in the least bit toasty, with only the normal airflow to cool it. I was thinking about the material used in the seals. On MTB that is usually rubber and on road bikes often some sort of fiber. Very small, so the seal itself would likely burn up. It has more surface area than heat sinks used for integrated circuits which need to dissipate tens of watts, and FAR better airflow than you find inside most electronic equipment as well. And 2% of 200 is 4, by the way. But you have four bearings, so 1W each. There's nothing new in bearing seals, big selection: http://www.skf.com/au/products/beari...als/index.html The seal type is the last part of the bearing number. If you need tighter sealing or more free running seals, buy a bearing with a different suffix. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#16
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Sealed Bearings
On 03/06/16 03:40, Joerg wrote:
I was thinking about the material used in the seals. On MTB that is usually rubber and on road bikes often some sort of fiber. Very small, so the seal itself would likely burn up. I have never seen a fibre "seal" used on any bicycle bearing. All of the seals I've seen are rubber, and they most certainly do not "burn up". It has more surface area than heat sinks used for integrated circuits which need to dissipate tens of watts, and FAR better airflow than you find inside most electronic equipment as well. And 2% of 200 is 4, by the way. But you have four bearings, so 1W each. I used an on line estimator of bearing losses by SKF some time ago, to find out what they estimate bearing loses to be for a typical double sealed cartridge bearing as used in the wheels I had at the time. The bearings have a rubber seal on both sides. If I remember correctly, the loses per bearing were in the order of 0.5W at a road speed of 50km/h. 0.1W of that was rolling friction. I.e. sticky grease and friction in the ball cage. 0.4W was from the seal friction. So a total of about 1W per wheel at 50km/h. Hardly enough to raise the bearing temperature by some detectible level above ambient - even if the bike was stationary and being pedalled on rollers! -- JS |
#17
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Sealed Bearings
On Thu, 2 Jun 2016 19:16:44 +0100, "Ian Field"
wrote: "John B." wrote in message .. . On Wed, 1 Jun 2016 18:39:42 +0100, "Ian Field" wrote: "John B." wrote in message ... On Tue, 31 May 2016 21:38:48 +0100, "Ian Field" wrote: wrote in message ... With all the bikes I have I also have a bike for which I built the wheels on old Campy record hub on the back and DuraAce on the front. After getting this bike back from a friend who was saving it for me while I was not in the best of health I rebuilt the wheels with new balls and Campy grease. I have mostly modern wheelsets from Campy or Fulcrum (the people who make the modern Campy hubs etc.) These wheels have sealed bearings. These sort of bothered me when I saw them because of the drag of the seals. You can tell simply spinning the wheels in a stand. But I imagined that with the weight of a person this would be insignificant. For the last couple of days I have been riding the old Look and in fact you CAN feel the difference between the open bearings and the sealed. It does coast much further and with less noise. If you mean regular bearings like the ones used for gear box shafts; there's a choice between shielded and oil seal bearings. The oil seal type have noticeable friction, while AFAIK: the shielded type just have a stainless steel shield that doesn't have any actual contact with the inner ring. The oil seal type are only unavoidable if you need to contain oil. The shielded type are OK with grease, but not 100% at keeping road grit out. You over simplify, There are basically three types of cartridge bearing. Plain (open, no seals or shields), Shielded and Sealed. Evidently not simple enough for you - the discussion was not about open bearings. No it wasn't, but then, you are so accustomed to shouting "****wit" I thought it best to be overly cautious and cover all possible points of contention, as it is obvious from the "Great V-brake Discussion" that your mechanical abilities is, well, rather limited. Obviously it was a mistake as you still shout and scream. You're the one that keeps on ranting - and I've seen at least one other person on the receiving end. Yes, and you might see more. But one thing you won't see, is me calling someone that is trying to help me a "****wit". -- cheers, John B. |
#18
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Sealed Bearings
On Fri, 3 Jun 2016 14:28:29 +1000, James
wrote: On 03/06/16 03:40, Joerg wrote: I was thinking about the material used in the seals. On MTB that is usually rubber and on road bikes often some sort of fiber. Very small, so the seal itself would likely burn up. I have never seen a fibre "seal" used on any bicycle bearing. All of the seals I've seen are rubber, and they most certainly do not "burn up". It has more surface area than heat sinks used for integrated circuits which need to dissipate tens of watts, and FAR better airflow than you find inside most electronic equipment as well. And 2% of 200 is 4, by the way. But you have four bearings, so 1W each. I used an on line estimator of bearing losses by SKF some time ago, to find out what they estimate bearing loses to be for a typical double sealed cartridge bearing as used in the wheels I had at the time. The bearings have a rubber seal on both sides. If I remember correctly, the loses per bearing were in the order of 0.5W at a road speed of 50km/h. 0.1W of that was rolling friction. I.e. sticky grease and friction in the ball cage. 0.4W was from the seal friction. So a total of about 1W per wheel at 50km/h. Hardly enough to raise the bearing temperature by some detectible level above ambient - even if the bike was stationary and being pedalled on rollers! Could you have used "seal one side" bearings. I have a set of wheels with cartridge bearings and before I built the wheels I took the hubs apart and that is what they had. So (I guess) only 1/2W at 50 :-) -- cheers, John B. |
#19
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Sealed Bearings
On 6/2/2016 11:28 PM, James wrote:
On 03/06/16 03:40, Joerg wrote: I was thinking about the material used in the seals. On MTB that is usually rubber and on road bikes often some sort of fiber. Very small, so the seal itself would likely burn up. I have never seen a fibre "seal" used on any bicycle bearing. All of the seals I've seen are rubber, and they most certainly do not "burn up". It has more surface area than heat sinks used for integrated circuits which need to dissipate tens of watts, and FAR better airflow than you find inside most electronic equipment as well. And 2% of 200 is 4, by the way. But you have four bearings, so 1W each. I used an on line estimator of bearing losses by SKF some time ago, to find out what they estimate bearing loses to be for a typical double sealed cartridge bearing as used in the wheels I had at the time. The bearings have a rubber seal on both sides. If I remember correctly, the loses per bearing were in the order of 0.5W at a road speed of 50km/h. 0.1W of that was rolling friction. I.e. sticky grease and friction in the ball cage. 0.4W was from the seal friction. So a total of about 1W per wheel at 50km/h. Hardly enough to raise the bearing temperature by some detectible level above ambient - even if the bike was stationary and being pedalled on rollers! There are bearing shields made of various fibers, usually in phenolic resin: http://www.ib-bearings.com/product2.html -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#20
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Sealed Bearings
On Sunday, May 29, 2016 at 11:40:18 AM UTC-7, wrote:
With all the bikes I have I also have a bike for which I built the wheels on old Campy record hub on the back and DuraAce on the front. After getting this bike back from a friend who was saving it for me while I was not in the best of health I rebuilt the wheels with new balls and Campy grease. I have mostly modern wheelsets from Campy or Fulcrum (the people who make the modern Campy hubs etc.) These wheels have sealed bearings. These sort of bothered me when I saw them because of the drag of the seals. You can tell simply spinning the wheels in a stand. But I imagined that with the weight of a person this would be insignificant. For the last couple of days I have been riding the old Look and in fact you CAN feel the difference between the open bearings and the sealed. It does coast much further and with less noise. Has anyone else noticed this? From the discussion it would appear that the lost of 2% of the pedaling energy in the wheel bearings doesn't appear to be noticeable to most people. I most surely notice it so I assume that most of you ride well within your limits while a large part of my time I am at or near mine. And I am not a very fast rider anymore. |
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