Hmmm. I think that I can hear you oinking ...
Find the error, then, in what I wrote and calculated. What I calculated clearly shows that no matter the tension, so long as the spoke is in the elastic region of its stress strain curve, the same lateral force causes the same deflection.alfeng said:
Geez ...
What I get is that you don't get simple algebra, and what you think happened didn't happen at all. Feel free to find an error in my math or the equations. The result was simple: two wheels laced with the exact same spokes, with the spoke tension in one wheel different than in the other, the same lateral force applied to each wheel will produce the same displacement. The tension difference does not effect the result. That much is obvious if you understand the equation that gives force in terms of displacement, starting length, cross sectional area, and Young's modulus. In fact, Sheldon Brown's lateral deflection test, the one whose graph and tabular data was posted, verifies the equations are correct. In fact, what the equations say and what Brown's results say is exactly what knowledgeable wheel builders know and say. Carry on as you like, because no matter what you claim, the physical reality follows the equations.alfeng said:
Ah ...
Both of my equations for x1 and x2 are correct. Likewise correct is my expression for x2-x1. That's the sum of the math. It's all correct, and it shows that two wheels, one laced with spokes at a tension 10x the other and both laced with the same spokes, will show the same lateral displacement given the same lateral load applied to each rim, thus showing that stiffness doesn't vary with spoke tension. So point out the mathematical error. Point out the theoretical error. Be specific. Don't deflect as you've been doing with irrelevant come backs. Use my work to show the error that you think is there.alfeng said:
Uh ...
Hey, 'I' am the one who is sorry ...
Actually, Al, not only are you not critically thinking, you do not get the math and the truth given by the theory. Moreover, you can't even correctly model with words what is going on. First, improperly tensioned spokes, i.e., those that go slack at the bottom of the wheel, don't bend at the bottom of the wheel. In fact all the do is..........go slack and maybe rattle. Since they're slack there is no loading, therefore they don't bend. Spokes anywhere else on the wheel also don't bend. If you actually think the band, prove how that happens. By the way, your recent incoherent post does not prove anything, other than your poor math skills and inability to understand what is actually happening. Now, I notice that you've added the "what happens when a bicycle wheel is NOT properly tensioned" bit. Sigh. What has improper tensioning got to do with anything being discussed? Has anyone argued that improperly tensioned wheels are good things? Have you noticed how it's been several times people that aren't you that improperly tensioned spokes go slack at the contact patch? As for imaginary taco'd wheel with improperly tensioned spokes, please show the load path for that improperly tensioned spoke that in your world is developing a bending moment. As for you little math display shows that you have at least some understanding of the commutative law for multiplication. Congratulations. Kids don't learn that until elementary school, and here you are finally understanding it much later in life. Pat yourself on the back. Again, in order to divert people's attention away from your ignorance, you mention your hallowed Keeling curve, thus bringing up your political views, again, where they bare no relevance whatsoever. If you get all exited about anthropomorphic global warming, I suggest you go to a forum about said topic. As for the last comment, again, just as with your AGW comment it shows that you are unable to construct a proper argument re: spoke tension, know that your argument is weak, and thus you try to deflect attention from the topic at hand. Find a political forum if you want to discuss politics. This thread has nothing to do with politics whatsoever. The theory and the reality behind spoke tension and lateral stiffness has been the same for many, many years no matter who was in the White House. I'll say it again: point out specifically where my math was wrong and how that applies to the theory that you claim isn't correct.alfeng said:
Physics? Schmizics!?! Whether intentionally, or not, you have misread what I have been stating ... I have not been saying that "higher tension" will result in a laterally stiffer wheel since the presumption was that the tension would be ~100 Kgf in both cases ...Originally Posted by alienator .
Al, you ought to be careful with physics because you're making assumptions that don't hold. You had alleged that higher tension on the spokes builds a stiffer wheel. I demonstrated that it didn't. Both dhk2 and I said that a wheels stiffness is dependent on the rim, the number of spokes and the spring constant of the spoke, which is exactly the same as saying that if spokes are made of the same material, the one with the larger cross-sectional area will be the stiffer of the two. That's was also stated via the equations I gave. So, my demonstration that wheel stiffness is independent of spoke tension. The equations I gave didn't make any statement about the stiffness of butted spokes. To calculate the effective spring constant of a butted spoke you need to follow the procedure for calculating the effective spring constant for springs in series. Here, I'll help you out and give you the equation of effective stiffness for a double butted spoke:
