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#1
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Why are spokes bent on the end anyway?
Shouldn't the place where they come out be parallel with the rim? Are there just such hubs being made and if so why aren't they common place. I found a spoke had pulled itself out at the axle end yesterday. That along with the recent 'fatigue' thread, got me to thinking. TBerk |
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#2
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Why are spokes bent on the end anyway?
On 2008-04-27, TBerk wrote:
Shouldn't the place where they come out be parallel with the rim? Yes. Are there just such hubs being made Shimano makes them. http://www.gearreview.com/images/shi...ltegra-hub.jpg and if so why aren't they common place. One day they might be. |
#3
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Why are spokes bent on the end anyway?
On Apr 27, 6:24*pm, TBerk wrote:
Shouldn't the place where they come out be parallel with the rim? Are there just such hubs being made and if so why aren't they common place. I found a spoke had pulled itself out at the axle end yesterday. *That along with the recent 'fatigue' thread, got me to thinking. TBerk It's called straight-pull. I suppose it was historically difficult to make suitable hubs strong enough cheaply. And if it ain't broke, don't fix it. Properly built wheels with conventional J-bend spokes can last forever. Joseph |
#4
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Why are spokes bent on the end anyway?
On Sun, 27 Apr 2008 09:24:56 -0700 (PDT), TBerk
wrote: Shouldn't the place where they come out be parallel with the rim? Are there just such hubs being made and if so why aren't they common place. I found a spoke had pulled itself out at the axle end yesterday. That along with the recent 'fatigue' thread, got me to thinking. TBerk Dear T, Originally, modern single spokes were straight. They threaded directly into hubs on highwheelers and were laced radially. Tangent lacing, which is stronger, was invented early in 1874, roughly the beginning of the highwheeler era. But tangent lacing was practically ignored until 1885 by hundreds of highwheeler manufacturers, who happily used straight spokes and radial lacing, much like wagon wheels. Here are some simple 1890s radial straight-pull safety-bicycle hubs: http://www.nostalgic.net/index.asp?S...ull+hubs%2Ejpg Straight spokes can be tangent laced, but the hubs need little arms with holes drilled at different angles. Here are some complex 1890s tangnet direct-pull safety bicycle hubs: http://www.nostalgic.net/index.asp?S...l+hubs+1%2Ejpg http://www.nostalgic.net/index.asp?S...l+hubs+2%2Ejpg http://www.nostalgic.net/index.asp?S...l+hubs+3%2Ejpg http://www.nostalgic.net/index.asp?S...l+hubs+4%2Ejpg The modern Mavic Cosmos wheelset uses radial direct spokes on its simple front hub (like old highwheelers and the first pictures) and tangent direct spokes on its more complex rear hub (like the second set of pictures). Spokes with elbows and hubs with side holes keep things simple and allow different tangent lacing patterns--1x, 2x, 3x, and so on up to 8x. Spokes with elbows also resist wind-up better than straight spokes. By the 1890s, elbow spokes and hubs were replacing straight spokes and hubs. They work so well and are so easy to manufacture that they have over 99% of the bicycle market. Here's a page that shows several varieties of the old direct highwheeler spoke schemes: http://www.hochrad.info/hochradseite...20speichen.htm Here's a later 8-cross tangent highwheeler hub with elbows: http://i2.tinypic.com/5xq520p.jpg Cheers, Carl Fogel |
#5
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Why are spokes bent on the end anyway?
TBerk wrote:
Shouldn't the place where they come out be parallel with the rim? Are there just such hubs being made and if so why aren't they common place. I found a spoke had pulled itself out at the axle end yesterday. That along with the recent 'fatigue' thread, got me to thinking. TBerk This is what Jobst Brandt [1, p. 51] wrote about this: Because spokes often fail at the elbow, hubs have been built that use straight, elwowless spokes. [...] More recently, a hub was designed that used straight spokes threaded at both ends. One end screwed into the flanged while the other end used a conventional nipple. This hub allows only the one spoking pattern for which it was designed. It is also expensive and very difficult to repair if a spoke breaks in the hib. These drawbacks make it unlikely that such hubs will become popular. Another design [...] uses straight spokes identical to ordinary bicycle spokes, but with no elbow bend. These spokes are inserted through a wavy cup-shaped flange and end engaged in conventional spoke nipples at the rim. Even though the shape of the flanges permits only one spoking pattern, this method seems more promising than the threaded hub. I dug up some relatively old French and German patent documents related to elbow-less spokes. http://Radio-BIP.qc.ca/Velo/FR2653069.pdf http://Radio-BIP.qc.ca/Velo/DE3612772.pdf http://Radio-BIP.qc.ca/Velo/DE3216396.pdf http://Radio-BIP.qc.ca/Velo/FR2595993.pdf I guess you'd find these designs in stores by now if they were succesful. Alexandre [1] Jobst Brandt, "The Bicycle Wheel", Menlo Park: Avocet Inc., 1981 |
#7
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Why are spokes bent on the end anyway?
Because it's easier (less expensive) to make a flat flange with holes
around the edge and bend the spoke end than to leave the spoke straight and machine the more complex hub to accomodate it. I have straight's on one set of my MTB wheels, it ain't pretty (not from a machining POV)! - - Compliments of: "Your Friendly Neighborhood Wheelman" If you want to E-mail me use: ChrisZCorner "at" webtv "dot" net My website: http://geocities.com/czcorner |
#8
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Why are spokes bent on the end anyway?
Good info people, Thank you. TBerk |
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