TWU proffesor. Question on strings

Discussion in 'TW Questions/Comments' started by newyorkstadium, Nov 8, 2012.

  1. newyorkstadium

    newyorkstadium Semi-Pro

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    TW proffesor. Question on strings

    Is the tension loss data relevant to tennis playing conditions? Don't some strings rate of tension loss change over time? Would a longer testing process be more accurate?
     
    Last edited: Aug 15, 2013
  2. newyorkstadium

    newyorkstadium Semi-Pro

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    Bump. TW Staff, does TW Professor frequent this forum much?
     
  3. TW Staff

    TW Staff Administrator

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    We are sorry for the delay. We have passed your questions on to the TW Professor. He is very busy at the moment and will get to your questions as soon as possible.

    Thanks,

    Brittany, TW
     
  4. TW Professor

    TW Professor Administrator

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    The tension loss data indicates how fast and how much tension a string will lose compared to others. All strings lose a lot of tension right after stringing and with the first 100 hits or so. Polys lose the most, then nylon, then gut. But the loss of tension is not good or bad perse. It all depends on whether or not you like the feel after the initial tension loss and break in period. Polys are so stiff that even after tension loss, they are still stiff compared to other strings. After the break in period, the rate of loss slows a great deal and all strings stabilize to a very slow, continual tension loss. This will affect string deflection and dwell time, which, in turn, might affect the feel and trajectory of your shot.

    Strings that lose a lot of tension initially will lose more tension during the stabilization phase also. A longer test period would be able to chart this loss, but it is not worth the time to do so. When the string becomes "unplayable" is a subjective decision, not a measurable quantity, because it means different things to different people. Strings with comparable stiffness and tension loss numbers will probably feel similar and do so for similar time periods. That is how the numbers are useful to players--if you like a string with certain parameters, you will probably like other strings with similar numbers.
     
  5. newyorkstadium

    newyorkstadium Semi-Pro

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    Is it true that strings lose elasticity then go "dead"? This confuses me as tension loss should make the string more powerful.

    In terms of a gut/poly combo, will I get the most spin if the gut/poly both have high spin potential on the "string finder"?

    Does stringing a softer poly tighter give pretty similar performance to a stiffer string at a lower tension?

    Do you plan any data on elasticity loss?

    Finally, does a string with high spin potential have less durability, due to high string to ball friction?
     
    Last edited: Nov 16, 2012
  6. newyorkstadium

    newyorkstadium Semi-Pro

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    TW Staff, could you pass on the message that I have more questions, please?

    Sorry for the impatience, it's just my topic is near the bottom of the page.

    thanks
     
  7. TW Staff

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    Your message has already been passed on to the Professor. Unfortunately, he will not be in the office until next week.


    Brittany, TW
     
  8. newyorkstadium

    newyorkstadium Semi-Pro

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    Thanks. What day does he return?
     
  9. TW Staff

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    Just confirmed he won't be back into the office until around December 10.

    Brittany, TW
     
  10. mikeler

    mikeler G.O.A.T.

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    Typical professor. Never in during office hours, works 2 days a week and gets holidays plus summers off. :)
     
  11. TW Professor

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    Q1: "Going dead" means different things to different people. Some say it makes the racquet trampoline like and balls go flying with more power (most likely higher trajectory due to tension loss is making them go long) and others say that the stringbed gets stiffer, loses power, and hurts their arms. You're right, it doesn't make sense. I am presently doing experiments to figure this all out, but you will have to stay tuned, because it will be a while before I get it all up on the website.

    Q2:Gut/poly combos depend on which is in the main and in the cross. Gut works best as a main. When hybriding, it is best to look only at the string-to-string friction. You want the strings to slide on each other. Pick strings with low string-to-string coefficients of friction (on String Finder these can be see by clicking on the number in the spin potential box for the given string).

    Q3: In theory, if the resulting stiffness of the two strings is the same, they will feel similar.

    Q4: The closest thing we have to "elasticity loss" is the energy return category on the String Performance Database:
    http://twu.tennis-warehouse.com/learning_center/reporter.php

    Q5: High spin potential strings will move more on each other. This may create more wear, depending on the string. However, the wear will be spread out over a longer distance than a string that does not move much. I guess experience will be the best judge there.
     
  12. newyorkstadium

    newyorkstadium Semi-Pro

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    Thanks very much. I have another question.

    In terms of tension/elasticity loss, is there a difference between the tightly strung soft poly and the loose stiffer poly? Would there be a difference in durability?

    Which would provide more spin if the spin potential was similar?
     
    Last edited: Dec 17, 2012
  13. TW Professor

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    There are many general principles you can apply to strings, but you can't answer many very specific ones like these. We don't measure durability so I don't know. In general, if the string has a higher spin potential, it is likely to have more spin, all things being equal.
     
  14. newyorkstadium

    newyorkstadium Semi-Pro

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    I've read that a high tension string has more elasticity loss, because it's stretched more.

    High spin potential strings have high string-to-ball friction. Does this wear the strings out quicker?

    The string friction rankings is missing out on some strings like VS tonic. Also, the Pacific Classic has a different COF value from the string finder tool.

    Thanks again.
     
    Last edited: Jan 8, 2013
  15. newyorkstadium

    newyorkstadium Semi-Pro

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    bump................
     
  16. Ronaldo

    Ronaldo G.O.A.T.

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    Hope he does not go on a three hour cruise over the Holidays, eh?
     
  17. TW Professor

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    Lower tensions might add to spin because there would be lower friction between the strings so they can move laterally more easily and snap-back to induce spin. At the same time, stiffer strings tend to snap back faster and with more force. That will increase spin.

    I've never tested wear and friction. I doubt it makes much difference.

    The friction tools will continue to add missing strings. But adding new strings has priority over adding older ones. If there is a difference in COF between the two tools, go with the String Finder tool. I'll have to look into why there is a difference. There shouldn't be.
     
  18. newyorkstadium

    newyorkstadium Semi-Pro

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    I've read that a high tension string has more elasticity loss, because it's stretched more.

    From looking at your tension loss data, it appears that high tension strings (61lbs) have more tension loss. With 51lbs having the least, and 41 in the middle.
     
    Last edited: Jan 8, 2013
  19. newyorkstadium

    newyorkstadium Semi-Pro

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    Final question. Does synthetic gut play the same as a multi if all parameters are the same (elasticity, stiffness, spin potential)?
     
  20. TW Professor

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    Construction doesn't matter much to performance if all parameters are the same ... except perhaps in durability. A multi might wear and fray more.
     
  21. newyorkstadium

    newyorkstadium Semi-Pro

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    I am extremely contented with the info I have gleaned from this thread.

    Thanks and Merry Christmas
     
    Last edited: Dec 22, 2012
  22. newyorkstadium

    newyorkstadium Semi-Pro

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    Why does the Recoil 16/Big Banger Original 16 hybrid have such a low COF on the string friction rankings? The friction rankings has them as 0.062.

    Recoil 16 has an individual COF of 0.098 and Big Banger Original 0.082.

    You told me a hybrid should contain two strings with low COF.
     
    Last edited: Feb 5, 2013
  23. newyorkstadium

    newyorkstadium Semi-Pro

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    Also, do smooth polys work better in a gut main hybrid then textured or twisted poly? Do textured or shaped polys eat through the gut faster?
     
    Last edited: Feb 4, 2013
  24. newyorkstadium

    newyorkstadium Semi-Pro

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    Thirdly, looking at your recent articles, is the spin potential ranking on the string finder still the best way of judging how much spin a full bed string offers.
     
  25. TW Professor

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    The COF of a string measures the friction of the string sliding on itself. It is not a universal measure against every other string it could slide on. Each combination must be tested separately. So a string could slide better on another string than it does on itself. This is very common.
     
  26. TW Professor

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    I don't test durability, but it is logical to assume that an acutely shaped or rough poly might wear through the gut faster.
     
  27. TW Professor

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    Yes, spin potential is still the best way to compare which string is likely to provide the most spin. Open string patterns reduce friction just like choosing a lower COF does. Within an open pattern, the string with the lowest COF will move more and provide more spin upon snap-back.
     
  28. newyorkstadium

    newyorkstadium Semi-Pro

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    Is there any data I can use to get the spin potential of a hybrid?

    I've read a lot about textured strings losing there texture and becoming smooth, very quickly. In this sense, is the spin data on textured strings irrelevant?

    Some string are missing from the performance database and string finder. It's a long list but I can post it if it's helpful.
     
    Last edited: Feb 14, 2013
  29. newyorkstadium

    newyorkstadium Semi-Pro

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    On a seperate note, is it true that a smaller grip size enables more spin on groundstrokes, and more wrist snap on serves.

    Does it affect shot consistency, flat strokes/serves and volleys?
     
  30. newyorkstadium

    newyorkstadium Semi-Pro

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    Bump, since this is near the bottom of the page
     
  31. TW Staff

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    I'm going to jump in here if you don't mind because our TW Professor is extremely busy testing new product.

    There has been some discussion that smaller grips enable the player to use a little more wrist on their shots, and by doing so the player is able to generate bit more spin on their shots. This is a more modern discussion because classically players used larger grips to provide more wrist control and thus more control on their shots.

    More modern players like Rafael Nadal have switched to smaller grips so that they can use more wrist in their shots. However, this is not a proven science, but simply more of an opinion or a theory.

    Grip size ends up coming down to personal preference. The only way to find what works best for you is to try your different options yourself and see which one you like best.

    Andy, TW
     
  32. newyorkstadium

    newyorkstadium Semi-Pro

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    Thanks Andy. I'll bump my other question. Sounds like I may have to wait a few weeks for an answer.
     
    Last edited: Feb 14, 2013
  33. newyorkstadium

    newyorkstadium Semi-Pro

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    Is the TW Professor still busy?

    Thanks
     
  34. TW Professor

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    We tested several hybrids (and won't test more because the combinations are infinite!). Go here (it takes a long time for the page to load):

    http://twu.tennis-warehouse.com/learning_center/COFreporter.php

    Spin is caused mostly by the mains, so even if the cross string gets smooth by the main rubbing up and down its length, the main string will keep its texture (except in the groove where it is sliding). So, for as much as texture influences spin (sticky string-to-ball interaction is not as important as slippery string-to-string interaction), it shouldn't change much. But I have never tested that.

    There are strings missing from the database. The new ones will be filled as they come in as best as possible. We will probably not go backwards and add older strings (more than a year old).
     
  35. newyorkstadium

    newyorkstadium Semi-Pro

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    Some gauges of strings are missing. Also, some strings are in the performance database but there is no spin potential data.

    Do you plan any experiments on the effects of grip size on spin? It is said a smaller grip increases wrist flexion, rotation and accelerates pronation, which increases spin and head-speed. However, the science of this is not known. It is also said that a smaller gripsize improves serves, via increased wrist snap, but again there is no science on the subject.

    From your articles, it seems 60lbs tension increases spin more then 30lbs for cross strings. What about in between these figures, is 40 better then 60? Do you plan any experiments that go below 30lbs, as some TW posters have tried?

    Is there an at-home method to measure the COF of a string-bed?

    I have a list of the strings missing if you ever need it.

    Thanks
     
    Last edited: Jun 19, 2013
  36. newyorkstadium

    newyorkstadium Semi-Pro

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    Bump. Cheers
     
  37. newyorkstadium

    newyorkstadium Semi-Pro

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    Is the TW professor available, TW Staff?

    Thanks
     
  38. TW Staff

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    The TW Professor is currently on medical leave as he is recovering from surgery. Depending on the recovery time, he won't be back in the office for approximately 2-3 weeks.

    Brittany, TW
     
  39. newyorkstadium

    newyorkstadium Semi-Pro

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    Ok. Thanks for informing me.
     
  40. newyorkstadium

    newyorkstadium Semi-Pro

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    Is the TWU professor back in office yet? Thanks.
     
    Last edited: Jun 19, 2013
  41. newyorkstadium

    newyorkstadium Semi-Pro

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    Bump......
     
    Last edited: Mar 21, 2013
  42. TW Professor

    TW Professor Administrator

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    Short answer--maybe someday, but don't plan on it. There is only so much time!

    No plans at present. Maybe some time. Again, time!

    The experiments really serve to discover or establish a baseline or general principle and back it up with data. It is the principle that is most important and refinements can be made with the principle in mind. Once all the principles are discovered, then we can go back and optimize findings.

    You can get a general feel for which string has a higher or lower COF by doing a simplified version of what is in the video linked below. Pull the pendulum back the same each time and time how long it takes to go back and forth. The longer it takes the higher the COF. It won't give you an actual COF but you can use the time as a substitute to measure the relative friction of strings. You could dream up many ways to do something like this. The video is in section VII of this link:

    http://twu.tennis-warehouse.com/learning_center/spinexperiment.php

    Don't worry, I have a list also.
     
  43. newyorkstadium

    newyorkstadium Semi-Pro

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    Thanks for all you help and info.
     
    Last edited: Mar 25, 2013
  44. newyorkstadium

    newyorkstadium Semi-Pro

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    Which has the biggest on impact on friction, string type or coating?

    Can you re-use a string 10+ times for hybrid COF tests? Or will the COF increase each time you use the string, thus skewing the results. I plan to test some hybrids of my own.

    Thanks again for your help. This has all been really useful.
     
    Last edited: Apr 8, 2013
  45. newyorkstadium

    newyorkstadium Semi-Pro

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    Hi. I've added some more questions. These are my final questions. Tennis season has resumed for me now, so I'm done cramming in my off-season. Plus, I'm out of questions.
     
    Last edited: Jul 8, 2013
  46. TW Professor

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    The COF will continually change. You will be OK for 20 or so though. One way to test would be to have a test string to use first. Record your results and then try it again with that string after you have done a bunch of tests. That way you can see how much change has occurred.
     
  47. newyorkstadium

    newyorkstadium Semi-Pro

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    Thanks.

    Which has the biggest on impact on COF, string type or coating?
     
  48. TW Professor

    TW Professor Administrator

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    Coating will wear off quickly. String type will be generally more important.
     
  49. newyorkstadium

    newyorkstadium Semi-Pro

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    The coating will still be on for the COF test. Doesn't this mean the COF tests are measuring the coating, not the string? If coating wears off quickly, do strings like natural gut lose their protection against humidity?

    I've never had the coating wear off a string. I've had string's fray, but that's rare for me.
     
    Last edited: Jun 11, 2013
  50. TW Professor

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    Coating is probably the wrong word. Some strings may or may not have a greasy feel when they come out of the package. That also may or may not decrease friction ("grease" doesn't necessarily make sliding easier--the string material itself could be slipperier on itself than on the grease). All strings will both lose the oiliness, if it exists, and wear down such that the friction increases with use. The string is never the same. It is always changing (virtually every property is changing). All you can do is pick a time to measure it and say that at that time the properties are this or that, and then compare that to other strings tested the same way at the same usage. Obviously, right out of the package with several stabilization hits or break-in string rubs is the only practical way to do it.

    I don't know if gut changes its tolerance to humidity or not.
     

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