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#12
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Headset dead spot?
This is common and easy to fix, just squirt some toothpaste (whitening
formulations work best) into the headset and ride around for a few miles, it will become all smooth again, after that you can flush with water and add grease. On Wed, 02 Apr 2008 21:59:23 GMT, Williams wrote: [Note: Normally I would search the archives to find previous messages, but the Google Advanced Groups Search no longer works. Is there another tool for that?] It seems that my front wheel steering has a "dead spot" such that the front wheel wants to point straight ahead (like there is a detent). Is a headset adjustment called for? This is a Chris King threaded headset on a road bike. thanks, Craig |
#13
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Headset dead spot?
On Thu, 03 Apr 2008 02:19:20 GMT, Ryan Cousineau
wrote: Here's an artificially dented headset: http://home.comcast.net/~carlfogel/download/brinell.jpg Dear Carl: fine photo of wanton bike-part destruction (sure, sure, in the name of science...) but my curiosity is piqued by the rather curious artifact in the top left of the photo. No, not the dime. Further left. Dear Ryan, Hmmm . . . http://i31.tinypic.com/e9yzhi.jpg It could be a modern version of this: http://en.wikipedia.org/wiki/Image:H...mbassadors.jpg Put one eye at the lower left edge of your screen and the anamorphic blob turns into a skull: http://upload.wikimedia.org/wikipedi...mbassadors.jpg But it's more likely just an icon (a sort of red-faced Mr. Potato Head with a yellow cap?) introduced by some shareware used to trim photos made with the original $12.95 USB camera that led Fogel Labs down the well-paved path to its present location. It appears in several other priceless early works: http://home.comcast.net/~carlfogel/download http://home.comcast.net/~carlfogel/d...d/brinell2.jpg http://home.comcast.net/~carlfogel/d...nell2setup.jpg http://home.comcast.net/~carlfogel/download/C1.jpg http://home.comcast.net/~carlfogel/download/ http://home.comcast.net/~carlfogel/download/C3.jpg Cheers, Carl Fogel |
#14
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Headset dead spot?
Williams wrote:
[Note: Normally I would search the archives to find previous messages, but the Google Advanced Groups Search no longer works. Is there another tool for that?] It seems that my front wheel steering has a "dead spot" such that the front wheel wants to point straight ahead (like there is a detent). Is a headset adjustment called for? This is a Chris King threaded headset on a road bike. thanks, Craig probably the product of over-zealous fitting by the installer and subsequent brinelling damage. c.k. headsets require a custom attachment for the bearing press, and not everyone bothers to use one. |
#15
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Headset dead spot?
wrote:
Craig Williams wrote: [Note: Normally I would search the archives to find previous messages, but the Google Advanced Groups Search no longer works. Is there another tool for that?] It seems that my front wheel steering has a "dead spot" such that the front wheel wants to point straight ahead (like there is a detent). Is a headset adjustment called for? This is a Chris King threaded headset on a road bike. http://www.sheldonbrown.com/brandt/i...-steering.html I think Google can find that one. Anyway, you might add that to your favorites. not only is the premise of that article incorrect, it contains other significant inaccuracies. rotating bearings /do/ indeed have metallic contact up until the point of hydrodynamic separation. http://www.tribology-abc.com/calculators/e12_3.htm separation only occurs at significant speed. at higher loads, it may never occur. for you to contend that headset bearings are somehow different from all the other bearings on a bike for which hydrodynamic separation also does /not/ occur, is both ignorant and misleading. furthermore, another poster to this group actually bothered to do hardness testing of some headset bearings and found that low hardness bearing races indexed quickly, while those with harder races didn't. this is entirely in accordance with indexing being the product of overload, [true brinelling] not "fretting" [false brinelling]. |
#16
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Headset dead spot?
wrote:
someone wrote: [Note: Normally I would search the archives to find previous messages, but the Google Advanced Groups Search no longer works. Is there another tool for that?] It seems that my front wheel steering has a "dead spot" such that the front wheel wants to point straight ahead (like there is a detent). Is a headset adjustment called for? This is a Chris King threaded headset on a road bike. http://www.sheldonbrown.com/brandt/i...-steering.html I think Google can find that one. Anyway, you might add that to your favorites. Why did you object to the word Brinell in that article? The term itself is not at fault, nor was the - not surprisingly uncredited - OP in describing the problem. That is what indexed headsets refer to - the only question is whether it is Brinelling due to excessive load or ambient conditions. Brinell is a forceful indentation of a ball into a surface and it leaves a shiny dimple the shape of the ball. Head bearing races are eroded by fretting and have dimples that are neither shiny nor spherical. They are causes by the balls rolling across their design path in tiny excursions. so how do /you/ know which is which? did the o.p. sent you the headset and you've had a chance to examine it? since in reality you have NOT actually made these inspections, you're simply presenting underinformed presumption as fact. To the OP: is there a single dead spot, or do you find other 'resting spots' as you rotate the handlebars? They occur at regular intervals, one ball space apart, but the straight ahead one is largest because that is the position in which this damage occurs. The bearing balls in the front and rear of the head bearing leave fretting impressions and I think the article explains that adequately. no it doesn't [you don't] because it [you] fails to recognize true brinelling - something easily caused by overload. |
#17
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Headset dead spot?
On Apr 2, 7:48 pm, wrote:
someone wrote: [Note: Normally I would search the archives to find previous messages, but the Google Advanced Groups Search no longer works. Is there another tool for that?] It seems that my front wheel steering has a "dead spot" such that the front wheel wants to point straight ahead (like there is a detent). Is a headset adjustment called for? This is a Chris King threaded headset on a road bike. http://www.sheldonbrown.com/brandt/i...-steering.html I think Google can find that one. Anyway, you might add that to your favorites. Why did you object to the word Brinell in that article? The term itself is not at fault, nor was the - not surprisingly uncredited - OP in describing the problem. That is what indexed headsets refer to - the only question is whether it is Brinelling due to excessive load or ambient conditions. Brinell is a forceful indentation of a ball into a surface and it leaves a shiny dimple the shape of the ball. Head bearing races are eroded by fretting and have dimples that are neither shiny nor spherical. They are causes by the balls rolling across their design path in tiny excursions. Brinell is a hardness test and leaves indentation as you mention. Brinelling is the result of overloaded bearings and may or may not leave identical impressions. Brinelling, whether 'true' or 'false', of actual bearings in use does not happen in a single test at 3000 kg, hence the markings will vary. The word migrated due to the similarity in bearing race damage. As an example, if someone called you a horse's ass, that does not mean you are an actual horse's ass, they are just commenting on the similarity. To the OP: is there a single dead spot, or do you find other 'resting spots' as you rotate the handlebars? They occur at regular intervals, one ball space apart, but the straight ahead one is largest because that is the position in which this damage occurs. The bearing balls in the front and rear of the head bearing leave fretting impressions and I think the article explains that adequately. I am surprised that you were unable to decipher 'To the OP:' correctly. It seemed straightforward when I wrote it... R |
#18
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Headset dead spot?
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#19
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Headset dead spot?
In article ,
wrote: On Thu, 03 Apr 2008 02:19:20 GMT, Ryan Cousineau wrote: Here's an artificially dented headset: http://home.comcast.net/~carlfogel/download/brinell.jpg Dear Carl: fine photo of wanton bike-part destruction (sure, sure, in the name of science...) but my curiosity is piqued by the rather curious artifact in the top left of the photo. No, not the dime. Further left. Dear Ryan, Hmmm . . . http://i31.tinypic.com/e9yzhi.jpg It could be a modern version of this: http://en.wikipedia.org/wiki/Image:H...mbassadors.jpg Put one eye at the lower left edge of your screen and the anamorphic blob turns into a skull: http://upload.wikimedia.org/wikipedi...mbassadors.jpg But it's more likely just an icon (a sort of red-faced Mr. Potato Head with a yellow cap?) introduced by some shareware used to trim photos made with the original $12.95 USB camera that led Fogel Labs down the well-paved path to its present location. It appears in several other priceless early works: http://home.comcast.net/~carlfogel/download http://home.comcast.net/~carlfogel/d...d/brinell2.jpg &c. Well, that explanation was surprising, the creature is still confusing (surprised they didn't at least use something that advertised their software), and I learned about Holbein's remarkable painting. Another good evening for Usenet. -- Ryan Cousineau http://www.wiredcola.com/ "In other newsgroups, they killfile trolls." "In rec.bicycles.racing, we coach them." |
#20
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Headset dead spot?
On 2008-04-03, jim beam wrote:
Williams wrote: [Note: Normally I would search the archives to find previous messages, but the Google Advanced Groups Search no longer works. Is there another tool for that?] It seems that my front wheel steering has a "dead spot" such that the front wheel wants to point straight ahead (like there is a detent). Is a headset adjustment called for? This is a Chris King threaded headset on a road bike. thanks, Craig probably the product of over-zealous fitting by the installer and subsequent brinelling damage. c.k. headsets require a custom attachment for the bearing press, and not everyone bothers to use one. Do you mean they got brinelled as they were hammered into the frame? That's one I've not heard. I thought in the usual "true brinelling" version of events, the brinelling happens when you ride over a nasty bump with the front wheel? |
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