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#11
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Tied and soldered spokes.
On 20 Nov, 18:38, Ian Smith wrote:
On Fri, 20 Nov 2009 17:22:32 +0000, Tom Anderson wrote: *On Thu, 19 Nov 2009, Marc wrote: thirty-six wrote: Tying and soldering the spokes will diminish the possibility of a radial buckle in a lighweight rim when heavily loaded. A desperate troll for attention. *Played for, and got. Out of interest, however, has anyone ever seen a purely radial buckle on a bicycle wheel? If you find yourself a 400g shallow section rim I can give you a description of horw to perform a radial buckle when 'building', for that is how i managed to get mine. It takes a bit of effort to get it this wrong, but actually doing it this bad was enlightening to me. |
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#12
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Tied and soldered spokes.
On Nov 21, 3:38*am, Ian Smith wrote:
On Fri, 20 Nov 2009 17:22:32 +0000, Tom Anderson wrote: *On Thu, 19 Nov 2009, Marc wrote: thirty-six wrote: Tying and soldering the spokes will diminish the possibility of a radial buckle in a lighweight rim when heavily loaded. A desperate troll for attention. *Played for, and got. Out of interest, however, has anyone ever seen a purely radial buckle on a bicycle wheel? I've dented a rim wall (think severe pinch flat territory). Does that count? James |
#13
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Tied and soldered spokes.
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#14
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Tied and soldered spokes.
Ian Smith wrote:
On Fri, 20 Nov, wrote: On Nov 21, 3:38 am, Ian Smith wrote: Out of interest, however, has anyone ever seen a purely radial buckle on a bicycle wheel? I've dented a rim wall (think severe pinch flat territory). Does that count? I don't think so. In fact, it would tend to demonstrate the case that they don't happen - you can hit the rim hard enough to cause plastic material failure and no radial buckle occurred. Like James, I've dented a rim wall but without buckling the rim as a whole - I have seen a radial buckle, but in a motor cycle wheel. I reckon it is possible to radial buckle a wheel but you have to hit it very hard indeed. The other thing with a pedal cycle wheel is that to get a purely radial buckle you'd not only have to hit it very hard, but also dead square, otherwise it will buckle laterally as well. Then you could argue for days about whether that counts as a radial buckle. -- Andrew |
#15
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Tied and soldered spokes.
Ian Smith wrote:
On Fri, 20 Nov, wrote: On Nov 21, 3:38 am, Ian Smith wrote: Out of interest, however, has anyone ever seen a purely radial buckle on a bicycle wheel? I've dented a rim wall (think severe pinch flat territory). Does that count? I don't think so. In fact, it would tend to demonstrate the case that they don't happen - you can hit the rim hard enough to cause plastic material failure and no radial buckle occurred. Like James, I've dented a rim wall but without buckling the rim as a whole - I have seen a radial buckle, but in a motor cycle wheel. I reckon it is possible to radial buckle a wheel but you have to hit it very hard indeed. The other thing with a pedal cycle wheel is that to get a purely radial buckle you'd not only have to hit it very hard, but also dead square, otherwise it will buckle laterally as well. Then you could argue for days about whether that counts as a radial buckle. -- Andrew |
#16
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Tied and soldered spokes.
On 21 Nov, 20:16, Naqerj wrote:
Ian Smith wrote: On Fri, 20 Nov, wrote: *On Nov 21, 3:38 am, Ian Smith wrote: Out of interest, however, has anyone ever seen a purely radial buckle on a bicycle wheel? *I've dented a rim wall (think severe pinch flat territory). Does *that count? I don't think so. *In fact, it would tend to demonstrate the case that they don't happen - you can hit the rim hard enough to cause plastic material failure and no radial buckle occurred. Like James, I've dented a rim wall but without buckling the rim as a whole - I have seen a radial buckle, but in a motor cycle wheel. *I reckon it is possible to radial buckle a wheel but you have to hit it very hard indeed. *The other thing with a pedal cycle wheel is that to get a purely radial buckle you'd not only have to hit it very hard, but also dead square, otherwise it will buckle laterally as well. *Then you could argue for days about whether that counts as a radial buckle. I'm guessing this wasn't a motocross wheel which had the crossings tied and soldered, because they do it so as not to collapse wheels. More likely the trailing and leading spokes dont touch so the wheel is unable to benefit from the locking together of spokes as required by Palmer. (No not Harold, but C A). When the load is big enough in comparison to the radial stiffness, the rim will buckle, this is epecially prevelant in lightweight bicycle rims and I mean 10oz and less. These do get trashed (did) because of radial buckling. The wheels which were susceptible were not tied and soldered, those that were tied would have their ties examined and possibly re-soldered before the start of a new season. |
#17
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Tied and soldered spokes.
On Sat, 21 Nov 2009 20:16:35 +0000, Naqerj wrote:
Ian Smith wrote: On Fri, 20 Nov, wrote: On Nov 21, 3:38 am, Ian Smith wrote: Out of interest, however, has anyone ever seen a purely radial buckle on a bicycle wheel? I've dented a rim wall (think severe pinch flat territory). Does that count? I don't think so. In fact, it would tend to demonstrate the case that they don't happen - you can hit the rim hard enough to cause plastic material failure and no radial buckle occurred. Like James, I've dented a rim wall but without buckling the rim as a whole - I have seen a radial buckle, but in a motor cycle wheel. I reckon it is possible to radial buckle a wheel but you have to hit it very hard indeed. The other thing with a pedal cycle wheel is that to get a purely radial buckle you'd not only have to hit it very hard, but also dead square, otherwise it will buckle laterally as well. Then you could argue for days about whether that counts as a radial buckle. It would be relatively simple to determine whether it was a radial buckle - you'd need to plot distance of rim from hub centre and see if you had an elastic-type variation from constant, then destress the wheel and see if it recovers. Every lateral buckle I've seen on a bicycle wheel looks like a near-enough purely lateral buckle - the 'pringles' look. I don't think you can load a bicycle wheel on a bicycle to a level that causes a radial buckle without first triggering either a plastic failure, or a lateral buckle. It's like an euler strut - you can't actually make pin-ended strut buckle into a two-half-wave mode (even though such a load and failure exists mathematically) , because it will fail to a one-half-wave mode first. regards, Ian SMith -- |\ /| no .sig |o o| |/ \| |
#18
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Tied and soldered spokes.
"Ian Smith" wrote in message
. .. It's like an euler strut - you can't actually make pin-ended strut buckle into a two-half-wave mode (even though such a load and failure exists mathematically) , because it will fail to a one-half-wave mode first. Is the former S-shape and the latter C-shape? (or maybe (-shape :-) ) |
#19
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Tied and soldered spokes.
On Sun, 22 Nov, Clive George wrote:
"Ian Smith" wrote in message . .. It's like an euler strut - you can't actually make pin-ended strut buckle into a two-half-wave mode (even though such a load and failure exists mathematically) , because it will fail to a one-half-wave mode first. Is the former S-shape and the latter C-shape? (or maybe (-shape :-) ) Yes - if you load a pin-ended strut axially it can (in theory) buckle to one of any number of modes, but because the first buckling mode can occur at a lower force than any of the others, it happens first. So in principle you can load a strut and have it buckle in an S-shape with two half waves, but in practice, unless you do very specific things, it will buckle to a C-shape before you get to the load that the maths says can cause a S-shape. [Specific things would include restraining the mid-point in such a way that it can't deflect but can rotate - then you'd be likely to get a S-shape buckle]. Likewise, I think you'll always get a lateral buckle from a wheel before you get a radial buckle. You might get a material failure before you get a radial buckle, but I'm not sure about that (which can also occur in the strut case - if your strut is stiff enough, you might actually crush it before it buckles). regards, Ian SMith -- |\ /| no .sig |o o| |/ \| |
#20
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Tied and soldered spokes.
On 22 Nov, 18:08, Ian Smith wrote:
Likewise, I think you'll always get a lateral buckle from a wheel before you get a radial buckle. If always, then wheels have too poor a lateral stability. The loads are predominantly radial so radial failures should be the dominant failure mode. The radial buckle is caused by rotation of the rim wrt the hub, making 1/2 the spokes tighten and half of them slacken. It's something you may see on a motorcross wheel but unlikely on anything but the lightest rimmed bicycle wheels prbably powered by Chris Hoy. *You might get a material failure before you get a radial buckle, but I'm not sure about that (which can also occur in the strut case - if your strut is stiff enough, you might actually crush it before it buckles). Thin walled rims, less than 1mm have curved braking surfaces which help to prevent crumpling. |
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