Discussion in 'TW Questions/Comments' started by newyorkstadium, Nov 8, 2012.
My point is don't most strings have an outer wrap/coating that, once broken, leaves just the frail string.
If so, it isn't the COF of the string type you are testing, but the COF of the outer wrap/coating. So the COF of a string is dependent on the coating, not the string underneath. Thus with the right coating, a natural gut or nylon could have a low COF.
Is there an at-home method for the stabilisation hits? By string rubs, do you mean rub the strings together, or just rub the string with my fingers or a cloth?
Your TWU data shows that pre-stretching a string increases the stiffness and energy return. Talktennis members have also reported that pre-stretching lowers the elasticity. Does this increase in stiffness, energy return, and lower elasticity mean the TWU COF and COF ball data becomes irrelevant for pre-stretched strings? This is a big negative for me, as I rely heavily upon the COF data to pick strings.
Does pre-stretching increase or decrease durability? I've seen a few strings on TW, like X-1 biphase, that mention pre-stretching increases durability.
A final question, that no-one seems to understand in the string forum. Why does the TWU data show that pre-stretching lowers the stiffness for natural gut?
Thanks a lot.
Very helpful info....both question and response! I really know nothing of string/stringing! And I should!!!
Can you look at my questions above please TW Professor? This has all helped immensely with preparation for an experiment I'm planning.
The Professor is currently out of the office. I will let him know when he gets back.
I've updated my message. Could you pass on my updated questions, please?
I've added further questions. It is post number 52. Thanks.
Bump, since this is right at the bottom of the page, and the TW Professor is online atm.
Whether it does or not, it is what it is. That is what you play with and that is what we test. The COF of all strings changes with use. We test out of the package and with a preliminary rubbing of the test strings against each other 20 times to condition the strings a bit.
As above, we rub the strings together with the 50 lb load on the strings.
Pre-stretching does not lessen elasticity. Perhaps players mean that it stretches or deflects less. That is true because at the same tension it is stiffer. Also, perhaps they mean that it feels less lively because the ball gets crushed more. Again true because the string is stiffer. More energy return means the string returns more of the energy that goes into it. But the stiffer the string, the more energy that goes into the ball, and the ball loses much more energy upon deformation than does the string. So, after impact, the ball will have less energy and lower velocity when pre-stretched. The COF data really isn't involved in these considerations.
If anything, pre-stretching might lead to more breakage because, being stiffer at any given tension, the peak impact force will be greater. So depending on where you hit, how hard, and the strength of the string, sure it may not last as long. However, I think most people who pre-stretch a string will string it at a lower tension so that would lessen the potential of breaking.
Gut does not behave like poly or nylon. Being a natural substance it does not have the polymer chain configuration of the synthetic material and behave differently. One of the amazing things about gut is that it is usually stiff at low tensions and softer at high tensions. At higher tensions it will stretch more for a given increase in tension, as opposed to all other strings that stretch less. Pre-stretching gut may make this happen at lower tensions than usual. It might be like stretching your muscles before working out.
Thanks for offering your knowledge and help, TW Proffessor. This thread has been extremely informative. I have no more questions.
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