Pro-Lite Bracciano Wheelset c/w spoke ties

Discussion in 'Road Cycling' started by Eichers, Feb 20, 2013.

  1. Eichers

    Eichers New Member

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    Hi All, just brought a Bracciano Wheelset and I thought that I would show you a pic of the rear wheel c/w spoke ties ... just for you CampyBob /img/vbsmilies/smilies/smile.gif

    [​IMG] [​IMG]

    I guess 2xNDS spoke tensions need to be helped in anyway that helps ... and the spoke ties will help in this case /img/vbsmilies/smilies/smile.gif
    Although I think 3xNDS will do at least as good a job (if not better), give a better ride, and handle torque effects a little better (although 3xNDS wouldn't look as good) /img/vbsmilies/smilies/smile.gif
     
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  2. alienator

    alienator Well-Known Member

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    Spoke ties don't do anything to address spoke tension. Zip. They also don't do anything to improve lateral stiffness for a wheel. They do a good job, though, of keeping broken spokes from flying around. Nice wheels, BTW. What do they weigh?
     
  3. Eichers

    Eichers New Member

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    Thanks Alienator, they are nice although they could be a little stiffer but then I could be a little lighter /img/vbsmilies/smilies/smile.gif

    Have a look at this http://www.pro-liteoz.com/store/index.php?act=viewProd&productId=19 or http://www.chainreactioncycles.com/Models.aspx?ModelID=29086

    Weight: Front 618g, Rear 864g = 1482g (about 1500g)

    Haven't ridden them as yet, so I will let you know if they feel like they are stiffer and I will also do the lateral force rim/brake pad test /img/vbsmilies/smilies/smile.gif
     
  4. Eichers

    Eichers New Member

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    Hey alienator, I gave some further thought to what you have written, and yes you are right when the wheel is static (no torque, lateral, radial forces are being applied ... not riding)

    ... but when torque, lateral, radial forces are applied, this is when the mechanics of the spoke tie has an effect on each spokes tension/detension cycle. While one spoke is pulling and the other spoke is pushing (one spoke is in tension while the other spoke is in detension), and because these two spokes are tied, the 2 spokes should assist each other during each spokes tension/detension cycle. If this is the case then the NDS tension (while riding) would appear as though the NDS spoke tension was higher, than what it is when the wheel is static (not riding) /img/vbsmilies/smilies/smile.gif

    CampyBob, what do you think ... sound reasonable ... /img/vbsmilies/smilies/smile.gif


    Nonetheless, even if the spoke tieing does do this, 3xNDS would still control torque effects better, improve the static NDS spoke tension, and make the wheel a little more compliant (give a better ride) ... now, if the previous analogy is correct then imagine 3xNDS with 2 spokes tied /img/vbsmilies/smilies/biggrin.gif
     
  5. alienator

    alienator Well-Known Member

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    Nope, that doesn't work either. The tie and solder can't prevent a spoke from stretching or relaxing.
     
  6. jpr95

    jpr95 Active Member

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    Are spokes in equal tension all around the wheel when the bike is being ridden? Or do they go from a state of highest tension when they're at the 12 o'clock position to one of lowest tension when they're at the 6 o'clock position?
     
  7. alienator

    alienator Well-Known Member

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    Spoke tension decreases very and through the area over the contact patch. It then quickly returns to its original tension.
     
  8. CAMPYBOB

    CAMPYBOB Well-Known Member

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    Cut the ties and loosen each spoke nipple precisely 2-1/4 turns.

    This will stiffen up the wheel.

    No, really. I've seen 'the chart'â„¢. It's on the intarwebz so it's got to be true!


    Nice wheel, KLabs!
     
  9. jpr95

    jpr95 Active Member

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    So that would mean that tying and soldering spokes would distribute the change in tension to any attached spokes. Sounds like it would stiffen the wheel to me.
     
  10. alienator

    alienator Well-Known Member

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    Nope. It doesn't mean that at all. Try showing the load path for that. There isn't one.
     
  11. CAMPYBOB

    CAMPYBOB Well-Known Member

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  12. Eichers

    Eichers New Member

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    I will do the super special lateral/climbing force rim/brake pad test ... these tests should put everything beyond doubt ... trust me [​IMG]
     
  13. Eichers

    Eichers New Member

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    I have given this a little further thought and I said this ...
    but I think it should have said this ...

    ... but when torque, lateral, radial forces are applied (dynamically - while riding) this is when the mechanics of the spoke tie may have an effect on each spokes tension/detension cycle. For example, while one spoke is pulling and the other spoke is pushing (one spoke is in tension while the other spoke is in detension), and because these two spokes are tied, the 2 spokes should assist each other during each spokes tension/detension cycle. If this is the case then each NDS spokes tension (while riding - sprinting/climbing) should remain tensioned even during the detension cycle (ie. closer to static tension) /img/vbsmilies/smilies/smile.gif
     
  14. alienator

    alienator Well-Known Member

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    Nope. Physics isn't on your side. If spokes don't remain tensioned all throughout a wheel rotation, you've either hit a massive obstruction/pothole and likely damaged your wheel, or your wheel was never properly tensioned to begin with. In a properly built wheel, the spokes are always under tension whether they're over the contact patch or not. Also, as an FYI, so long as the spokes don't go slack (i.e. lose all tension), the stiffness of the wheel won't change. Wheel stiffness is a function of spoke diameter, the number of spokes, the lacing pattern, rim stiffness.... Note that so long as spokes don't go slack, tension does not effect stiffness. Despite the opinions of far too many cyclists and a frightening number of Americans, science and engineering really do work in the real world. Yep. Equations, constants, and calculations really are relevant. Maybe some LBS guy doesn't get that, some machinist can't understand the concepts, or some magazine journo keeps perpetuating myths. None of that changes the scientific truth. There will always be scientifically illiterate people, but with a little work, we can make those Americans the minority.
     
  15. Eichers

    Eichers New Member

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    Thanks alienator, be interesting to see these equations, constants, and calculations /img/vbsmilies/smilies/smile.gif
     
  16. alienator

    alienator Well-Known Member

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    No equations are needed in this case because there is no constraint placed by the tie and solder on the elasticity of the spoke. None. The elasticity of the spoke is a material property. Further there is no load path that transfers load from one spoke into a tie and solder wrap and then into a second spoke. The tie and solder wrap is not a load bearing member so it doesn't reduce the load on a spoke. The one thing a tie and solder wrap can do is alter the frequencies of vibration. In essence a tie and solder wrap is a high pass filter, allowing "high" frequency vibes while preventing low frequency vibes. That's got nothing to do with the load, though, and is only a function of the length of free spoke in question. Since a tie and solder job shortens the lengths of free spoke, it prevents low frequency (i.e. long wavelength) vibrations from existing in the spoke. Of course you're free to by into quack notions if real science doesn't match your assumptions.
     
  17. Eichers

    Eichers New Member

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    Hey alienator, this spoke tie is not soldered ... it is a brace ... http://velostage.com/pro-lite-bracciano-review/

    [​IMG]

    What effect do you believe "low frequency (i.e. long wavelength) vibrations" have on a spoke?

    If low frequency (i.e. long wavelength) vibrations do have an effect then spoke shape should also be important, shouldn't it ...
     
  18. alienator

    alienator Well-Known Member

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    Yeah, that brace isn't doing much. What effect do low frequency vibes have on a spoke? They'll have some effect on how vibration damping in a wheel behaves. If I haven't deleted it, somewhere I've got data on vibration damping in wheels from some tests I did for a manufacturer, and if I remember the vibe spectra correctly, low frequency vibes were of a much lower amplitude than higher freq. vibes. That means that they weren't the dominant vibes. It was the case for traditionalish wheels and for CF wheels and CF wheels with CF spokes. Vibes are inevitable since bikes are never pedaled on perfectly smooth surfaces and are just the result of energy put into the wheel by the road. The energy excites bending modes in the spokes (which vary with lacing pattern, spoke material, and spoke homogeneity), and thus the spokes vibrate. Higher frequency vibrations have more energy than lower frequency vibrations. As it happens the typical way that high freq vibes are damped is with mass, so this means heavier bike wheels will damp high freq vibes better than lighter wheels.
     
  19. Eichers

    Eichers New Member

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    Hi alienator, I went away and had a think about this and I agree that it is good that the spoke bracing helps control Standing Wave Resonances that will occur in the spoke during a spokes tension/detension cycle (especially during the detension segment of the cycle) but I believe that there is another benefit which is not revealed during Static testing /img/vbsmilies/smilies/smile.gif

    Yes, you are correct ... Statically, there is no difference in Static Lateral Stiffness but I believe there is an improvement in the wheels Dynamic Lateral Stiffness (while Riding).
    I believe that the spoke bracing (tieing and soldering) improves a spokes tension/detension cycle stiffness, especially during the detension segment of the cycle where it can slack, which directly improves a wheels Dynamic Lateral stiffness /img/vbsmilies/smilies/smile.gif

    To test this it would need to be down Dynamically (while riding), because a Static test will not show this result /img/vbsmilies/smilies/smile.gif
    I believe that CampyBob is correct, even though he does not know why he is correct ... no offense CampyBob /img/vbsmilies/smilies/smile.gif

    Nonetheless, a 3xNDS lacing will be more Dynamic Laterally Stiff than a 2xNDS lacing, because the 3xNDS lacing improves a spokes tension/detension cycle stiffness /img/vbsmilies/smilies/smile.gif

    interesting ... Thanks KL /img/vbsmilies/smilies/smile.gif
     
  20. danfoz

    danfoz Well-Known Member

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    That's the most smileys I've seen in one post /img/vbsmilies/smilies/smile.gif
     
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