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#61
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Residual stress, fatigue and stress relief
daveornee wrote:
jim beam Wrote: daveornee wrote: Ron Ruff Wrote: On Apr 24, 9:59*pm, jim beam wrote: manufacturers actually state that spokes /shouldn't/ be bent. Everybody I know who uses Sapim spokes bends them. Dave Ornee, what do you do? I bend the heads in ones to a slightly smaller angle (depending on the hub, crossing pattern and rim ERD) with spokes laced and nipples turned 5 full turns. Some hubs like Phil Wood have canted flanges so I don't bend spokes on them unless it looks like it will improve the spoke line. Yes, I saw what Sapim says on their web site about not bending, but I find that the improved spoke line is benenficial in the long run. I have had one returned wheel from over 1,000 built with a broken spoke... and it broke at the end of the spoke shaft just at the elbow. I tossed the spoke and all 31 of the others in the wheel (no pictures as I forgot to take the time and wanted to get the wheel back to the rider) and rebuilt it with all new spokes and new nipples. Hub is Dura Ace 7700 rear (25th Annivesary) rim is Velocity Fusion. I saw the spokes in Jim Beams pictures. That is interesting. Some day I will photograph spokes before & after... inbound and outbound + spoke holes prebuild and post build, including post stabilizing. this is the hub those spokes came from: http://www.flickr.com/photos/38636024@N00/104463818/ that hub hole deformation is *definitely* going to affect exit angle. and thus "correcting" the spoke line /before/ tensioning [and stabilizing], as most people do, is going to be premature. If any of you have such pictures already I would like to see them and get some suggestions how to get the details photographed such that you can really discern what is going on. Here are links to 6 pictures I took today of a Dura Ace HB-7700 32H wheel I built today with Sapim Race 14/15 DB spokes. One side I used my previous pattern of "correcting the spoke line" and the other side I made no such correction. Judge for yourself. http://www.flickr.com/photos/17085834@N08/2443679334/ http://www.flickr.com/photos/17085834@N08/2443679236/ http://www.flickr.com/photos/17085834@N08/2442851273/ http://www.flickr.com/photos/17085834@N08/2443679416/ http://www.flickr.com/photos/17085834@N08/2442851411/ http://www.flickr.com/photos/17085834@N08/2442851349/ After this experiment I think the next build will be done without correcting the spoke line. aren't modern digicams fantastic??? one other thing i've noticed, not that it really makes much difference, is that the spoke head on the "uncorrected" spoke always sits in the hub hole just that little bit better. |
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#62
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Residual stress, fatigue and stress relief
On Sun, 27 Apr 2008 04:22:58 +1000, daveornee
wrote: Here are links to 6 pictures I took today of a Dura Ace HB-7700 32H wheel I built today with Sapim Race 14/15 DB spokes. One side I used my previous pattern of "correcting the spoke line" and the other side I made no such correction. Judge for yourself. http://www.flickr.com/photos/17085834@N08/2443679334/ http://www.flickr.com/photos/17085834@N08/2443679236/ http://www.flickr.com/photos/17085834@N08/2442851273/ http://www.flickr.com/photos/17085834@N08/2443679416/ http://www.flickr.com/photos/17085834@N08/2442851411/ http://www.flickr.com/photos/17085834@N08/2442851349/ After this experiment I think the next build will be done without correcting the spoke line. Dear Dave, Nice pictures--thanks! Yikes! http://www.flickr.com/photos/17085834@N08/2443679416/ http://www.flickr.com/photos/17085834@N08/2442851349/ Cheers, Carl Fogel |
#64
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Residual stress, fatigue and stress relief
Wrote: [color=blue] On Sun, 27 Apr 2008 04:22:58 +1000, daveornee wrote: SNIP http://www.flickr.com/photos/17085834@N08/2443679416/ http://www.flickr.com/photos/17085834@N08/2442851349/ Cheers, Carl Fogel If you just built em and rode them without stabilizing them, they would look quite similar after riding them a short while. The difference is that you can put a controlled force amount in stabilizing them and get the wheels trued, tensioned, tension balanced, centered and they will stay that way for a long time. -- daveornee |
#65
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Residual stress, fatigue and stress relief
Wrote: [color=blue] On Sun, 27 Apr 2008 04:22:58 +1000, daveornee wrote: SNIP http://www.flickr.com/photos/17085834@N08/2443679416/ http://www.flickr.com/photos/17085834@N08/2442851349/ Cheers, Carl Fogel If you just built em and rode them without stabilizing them, they would look quite similar after riding them a short while. The difference is that you can put a controlled force amount in stabilizing them and get the wheels trued, tensioned, tension balanced, centered and they will stay that way for a long time. -- daveornee |
#66
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Residual stress, fatigue and stress relief
On Apr 25, 10:09*pm, jim beam wrote:
that hub hole deformation is *definitely* going to affect exit angle. and thus "correcting" the spoke line /before/ tensioning [and stabilizing], as most people do, is going to be premature. Exactly when and how much can be debated I suppose, but... Every hub I use supports the spoke in such a way as to make the heads-in spokes "stick out" ie they aren't heading straight to the rim but rather bow outward. Increasing tension (even overloading) will not eliminate this completely... so the spoke will end up with an additional bending load, if nothing else is done about it. This is not a good thing. Similarly, most rims I use do not allow spokes on the NDS and front spokes to enter without some bending load at the rim. Some large flange hubs create a pretty acute angle even on the DS. I prefer to "correct the spoke line" at the hub rather late in the building process, but before overloading. I agree that high tension is probably better for achieving the best "shape" at that point. At the rim I bend the spokes fairly early, just because it is too difficult to do well when the tension is high. It seems to me that it is better for the rim if the nipple lies more closely to perpendicular against the surface of the rim, to reduce the chance of eyelet deformation and cracking. |
#67
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Residual stress, fatigue and stress relief
Ron Ruff wrote:
On Apr 25, 10:09�pm, jim beam wrote: that hub hole deformation is *definitely* going to affect exit angle. and thus "correcting" the spoke line /before/ tensioning [and stabilizing], as most people do, is going to be premature. Exactly when and how much can be debated I suppose, but... Every hub I use supports the spoke in such a way as to make the heads-in spokes "stick out" ie they aren't heading straight to the rim but rather bow outward. only when the hub is new and the hub holes un-deformed. to bend the spoke a head of this deformation is premature because hub hole deformation changes the exit angle. and it's the angle to which spokes are pre-formed! Increasing tension (even overloading) will not eliminate this completely... so the spoke will end up with an additional bending load, if nothing else is done about it. that's not correct. both dave ornee and i have posted pics of spokes that are unbent, and when disassembled, they prove that bending was unnecessary. This is not a good thing. no, it's a misunderstanding and non-observation of the facts. see above. Similarly, most rims I use do not allow spokes on the NDS and front spokes to enter without some bending load at the rim. Some large flange hubs create a pretty acute angle even on the DS. I prefer to "correct the spoke line" at the hub rather late in the building process, but before overloading. I agree that high tension is probably better for achieving the best "shape" at that point. At the rim I bend the spokes fairly early, just because it is too difficult to do well when the tension is high. It seems to me that it is better for the rim if the nipple lies more closely to perpendicular against the surface of the rim, to reduce the chance of eyelet deformation and cracking. you have to overload to ensure bedding in - if you want your wheels to remain true at any rate. and if your spoke tension is high enough to cause rim deformation, it's too high - use a tension meter. |
#68
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Residual stress, fatigue and stress relief
jim beam wrote:
Ron Ruff wrote: On Apr 25, 10:09�pm, jim beam wrote: that hub hole deformation is *definitely* going to affect exit angle. and thus "correcting" the spoke line /before/ tensioning [and stabilizing], as most people do, is going to be premature. Exactly when and how much can be debated I suppose, but... Every hub I use supports the spoke in such a way as to make the heads-in spokes "stick out" ie they aren't heading straight to the rim but rather bow outward. only when the hub is new and the hub holes un-deformed. to bend the spoke a head typo - "ahead" of this deformation is premature because hub hole deformation changes the exit angle. and it's the angle to which spokes are pre-formed! Increasing tension (even overloading) will not eliminate this completely... so the spoke will end up with an additional bending load, if nothing else is done about it. that's not correct. both dave ornee and i have posted pics of spokes that are unbent, and when disassembled, they prove that bending was unnecessary. This is not a good thing. no, it's a misunderstanding and non-observation of the facts. see above. Similarly, most rims I use do not allow spokes on the NDS and front spokes to enter without some bending load at the rim. Some large flange hubs create a pretty acute angle even on the DS. I prefer to "correct the spoke line" at the hub rather late in the building process, but before overloading. I agree that high tension is probably better for achieving the best "shape" at that point. At the rim I bend the spokes fairly early, just because it is too difficult to do well when the tension is high. It seems to me that it is better for the rim if the nipple lies more closely to perpendicular against the surface of the rim, to reduce the chance of eyelet deformation and cracking. you have to overload to ensure bedding in - if you want your wheels to remain true at any rate. and if your spoke tension is high enough to cause rim deformation, it's too high - use a tension meter. |
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