#31
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Bearing damage?
Tom Keats wrote:
smack. Brinelled bearings. specifically unjoyous deployment of a 4lb hammer when the car's own function can serve the purpose, and not damage anything. How come bottom bracket bearing do NOT have this problem when a hammer is used to drive cotter pins in [1] and out on cranks? [1] No, tightening is NOT done with the nut with attaching a cottered crank. When cotter pins have to be pounded in, there's something horribly wrong. It usually happens from the bike shop who doesn't quite have the exact match of what you require, and gives you what they consider the next closest thing. It's an all too common occurrence. Anyway, bearings get ruined by being used dry of grease/lubricant. I'd like to hear more about that. Who rides with lubricant free BB bearings? A number of Pacific Northwesters who frequently ride through deep puddles and torrential rainfalls, and don't maintain their bikes as well as they should for the prevailing conditions. Besides, no matter how you brace the spindle when pounding in cotters, the shock reaches the ball or two under the spindle. In You shouldn't have to pound them in. If you have to pound them in, they don't fit. Maybe tap them in a little, sure -- but to ~pound~ them in?! Nay. I see you don't work with these. They must be pressed in with enormous force to give enough preload and insure no "lift-off" from the small cotter face under hard torque. Those of us who lived through the steel crank + cotters can recall how they failed with excess torque if not installed forcefully enough. They must be driven in with a hammer or a special press. Not only that, the also needed to be filed to the right wedge angle to match the other crank in a one side replacement. The off-the-shelf cotter not being ready to install. The flat taper was only an indication of where the flat belonged because the threaded end was offset to pass under the spindle flat. Again, it is a retention nut, not one that can be used to install the cotter, it having insufficient strength for that task. addition, I saw many cranks secured without more than a 1/2 lb hammer held under the crank, yet no dents in the spindle resulted. Of course. The cotters were being smote with a hammer, not the spindles. I don't think I've ever seen a dented spindle. I've seen spindles with badly scoured cones, though. Because the bearings were run dry of lube. Where do you suppose the reaction force went if not through the spindle to the bearing cups? I still have cottered crank spindles lying around that have no sign of Brinelling although I have a few head sets where both top and bottom ball bearings as well a roller bearing ones have fretting dimples. In these rainy Pacific Northwest climes, the lower headset bearing gets the brunt of the weather, especially when unprotected by a front fender. The cup serves to guide splashed-up water into the bearing, washing the lube out. And it's a sneaky effect, because as long as the upper headset bearing is fine, everything can appear to be good. I don't think you analyzed the head bearings correctly. If they were being bathed in water, they would rust solid when parked. On inspection, they are not full of water and did not rust. As I explained, this is a fretting b=problem and that is why the upper head bearing also shows home position dimples. Fortunately this problem has been solved with current bearings. http://www.sheldonbrown.com/brandt/i...-steering.html Jobst Brandt |
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#32
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Minnesota Winters
On Fri, 19 Dec 2008 13:21:17 +0000, Clive George wrote:
"jim beam" wrote in message ... actually pretty easy to do this - simply loosen the lug nuts a couple of turns, then go drive around the block. a couple of hard braking episodes will break free the stubbornest of rusted wheels. God Danged Jim. Thats the only intelligent thing you've ever posted on this forum. I did that, and it worked with the front wheel but not the rear wheel. I had to take additional measures for the rear wheel, including putting some Liquid Wrench between the rim and hub and engaging in the telephone book rhumba -- you loosen the lug nuts and then drive the stuck wheel over a phone book, back and forth. Then you kick the wheel in strategic locations. That finally worked. Or maybe it was the swearing that did it. My 4lb club hammer was bought specifically to remove a wheel from my car. I'd tried the 1lb one, no joy, no matter how hard I went at it. 4lb one, smack, wheel off. smack. brinelled bearings. specifically unjoyous deployment of a 4lb hammer when the car's own function can serve the purpose, and not damage anything. And what sort of loads + impacts do the bearings get in normal use? why don't you work it out? mass. acceleration. point contact area. What impacts do they get when you're driving around with loose nuts? You're raising bogus worries. no, i'm speaking from experience of failure analysis. bearings that get hammered get brinelled and subsequently fail. this is not knowledge exclusive to scientists - technicians with shop experience long enough to see the consequences will tell you that. |
#33
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Minnesota Winters
On Fri, 19 Dec 2008 10:10:48 -0600, Tim McNamara wrote:
In article , "Clive George" wrote: "jim beam" wrote in message ... actually pretty easy to do this - simply loosen the lug nuts a couple of turns, then go drive around the block. a couple of hard braking episodes will break free the stubbornest of rusted wheels. God Danged Jim. Thats the only intelligent thing you've ever posted on this forum. I did that, and it worked with the front wheel but not the rear wheel. I had to take additional measures for the rear wheel, including putting some Liquid Wrench between the rim and hub and engaging in the telephone book rhumba -- you loosen the lug nuts and then drive the stuck wheel over a phone book, back and forth. Then you kick the wheel in strategic locations. That finally worked. Or maybe it was the swearing that did it. My 4lb club hammer was bought specifically to remove a wheel from my car. I'd tried the 1lb one, no joy, no matter how hard I went at it. 4lb one, smack, wheel off. smack. brinelled bearings. specifically unjoyous deployment of a 4lb hammer when the car's own function can serve the purpose, and not damage anything. And what sort of loads + impacts do the bearings get in normal use? What impacts do they get when you're driving around with loose nuts? You're raising bogus worries. Not our jim! timmy, why don't you tell us how you managed to calculate how 1800 5000? the mathematical world is on the edge of its seat. or not. because you're a retard. |
#34
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Bearing damage?
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#35
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Bearing damage?
On Sun, 21 Dec 2008 07:01:09 +0000, jobst.brandt wrote:
Tom Keats wrote: smack. Brinelled bearings. specifically unjoyous deployment of a 4lb hammer when the car's own function can serve the purpose, and not damage anything. How come bottom bracket bearing do NOT have this problem when a hammer is used to drive cotter pins in [1] and out on cranks? [1] No, tightening is NOT done with the nut with attaching a cottered crank. When cotter pins have to be pounded in, there's something horribly wrong. It usually happens from the bike shop who doesn't quite have the exact match of what you require, and gives you what they consider the next closest thing. It's an all too common occurrence. Anyway, bearings get ruined by being used dry of grease/lubricant. I'd like to hear more about that. Who rides with lubricant free BB bearings? Besides, no matter how you brace the spindle when pounding in cotters, the shock reaches the ball or two under the spindle. In addition, I saw many cranks secured without more than a 1/2 lb hammer held under the crank, yet no dents in the spindle resulted. says the great and mighty jobst brandt. not because it doesn't happen, but because his ego doesn't allow mistake admission and his lack of learning doesn't allow correction. I still have cottered crank spindles lying around that have no sign of Brinelling of course! jobst brandt looking for evidence of something that would evidence his gross ignorance is like the fda looking for evidence of mad cow disease after they've fired all their inspectors! although I have a few head sets where both top and bottom ball bearings as well a roller bearing ones have fretting dimples. no jobst, you have brinelling dimples. don't protect your ignorance like it's a virtue. |
#36
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Bearing damage?
On Sun, 21 Dec 2008 15:14:30 +0000, jobst.brandt wrote:
snip usual presumptive, mistaken and underinformed crap jobst, i know it's late in the day for you, but is there /any/ chance you'll open a book on materials and deformation before you die? it might stop you looking like a complete ass. |
#37
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Bearing damage?
jim beam wrote:
Jobst Brandt wrote: although I have a few head sets where both top and bottom ball bearings as well a roller bearing ones have fretting dimples. no jobst, you have brinelling dimples. *don't protect your ignorance like it's a virtue. How the hell would you brinell a _top_ race, or a roller bearing headset? Your determination to somehow declare Jobst wrong when he's not is strange and perverse, not to mention futile. Chalo |
#38
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Bearing damage?
On Mon, 22 Dec 2008 14:51:54 -0800, Chalo wrote:
jim beam wrote: Jobst Brandt wrote: although I have a few head sets where both top and bottom ball bearings as well a roller bearing ones have fretting dimples. no jobst, you have brinelling dimples. Â*don't protect your ignorance like it's a virtue. How the hell would you brinell a _top_ race, or a roller bearing headset? er, by lateral loading perhaps? by repeated impact perhaps? Your determination to somehow declare Jobst wrong when he's not is strange and perverse, not to mention futile. but he is wrong so it's not. or at least, not as futile as a guy that hasn't done his homework trying to argue with someone that has. bottom line, i don't understand your problem chalo. i understand jobst's - he doesn't do his homework, but has opinions anyway, and declares those underinformed opinions as fact. on topics where i just so happen to know more than he does. but you? you don't seem to understand the distinction between argument to establish fact in the face of utter bull****, and just argument with the argument. the latter is ****ing pointless. but you react like it's your whole raison d'etre. and as if it's personally insulting to you. from where i'm standing, i think you're wasting your electrons. |
#39
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Bearing damage?
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#40
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Bearing damage?
Tom Sherman wrote:
smack. Brinelled bearings. specifically unjoyous deployment of a 4lb hammer when the car's own function can serve the purpose, and not damage anything. How come bottom bracket bearing do NOT have this problem when a hammer is used to drive cotter pins in [1] and out on cranks? [1] No, tightening is NOT done with the nut with attaching a cottered crank. When cotter pins have to be pounded in, there's something horribly wrong. It usually happens from the bike shop who doesn't quite have the exact match of what you require, and gives you what they consider the next closest thing. It's an all too common occurrence. Anyway, bearings get ruined by being used dry of lubricant. I'd like to hear more about that. Who rides with lubricant free BB bearings? A number of Pacific Northwesters who frequently ride through deep puddles and torrential rainfalls, and don't maintain their bikes as well as they should for the prevailing conditions. Besides, no matter how you brace the spindle when pounding in cotters, the shock reaches the ball or two under the spindle. In addition, I saw many cranks secured without more than a 1/2 lb hammer held under the crank, yet no dents in the spindle resulted. I still have cottered crank spindles lying around that have no sign of Brinelling although I have a few head sets where both top and bottom ball bearings as well a roller bearing ones have fretting dimples. You shouldn't have to pound them in. If you have to pound them in, they don't fit. Maybe tap them in a little, sure -- but to ~pound~ them in?! Nay. I see you don't work with these. They must be pressed in with enormous force to give enough preload and insure no "lift-off" from the small cotter face under hard torque. Those of us who lived through the steel crank + cotters can recall how they failed with excess torque if not installed forcefully enough. They must be driven in with a hammer or a special press. Not only that, the also needed to be filed to the right wedge angle to match the other crank in a one side replacement. The off-the-shelf cotter not being ready to install. The flat taper was only an indication of where the flat belonged because the threaded end was offset to pass under the spindle flat. Again, it is a retention nut, not one that can be used to install the cotter, it having insufficient strength for that task.[...] See http://www.sheldonbrown.com/var/images/var0012.jpg. Nice item. As you can see, those were the "good old days" of bicycle mechanics. Fortunately Sheldon saved evidence of that. Jobst Brandt |
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