Low Friction Poly X's For Gut Mains : Softer Alternative to MSV Co-Focus?

[corners]

Originally Posted by newyorkstadium

So is the TW tension loss tool useless? I've been using it for a while?

No, I don't think it's useless. It's just that they are a bit rougher with the strings than they should be. Many of the copolys lose 25-30 pounds in their tests, but we know from people that keep string tension logs using various tension reading tools and devices that copolys usually lose about half that much tension after 10 hours or so of play. But in the tests, nylon strings lose about 10 pounds, on average, and gut loses 5 pounds or so. And this reflects real life: copolys lose the most tension, nylon strings lose less, and gut loses the least. And the numbers for nylon and gut are close to real life, so it's really only with the polys that the tests show greater than realistic tension loss. But even with the polys, some lose much more tension than others. So if can still use the test data to compare one poly to another: If one poly loses 25 pounds in the tests and another only loses 15, we can be pretty sure that the second poly is much better than the first, which is useful info.

In addition, if we're clever we can still use the test data to compare the stiffness and energy return, string deflection and dwell-time, of a poly to a nylon string, or a poly to a natural gut. The String Performance Database allows us to sort results by "actual tension" - the tension is really at after the tension loss protocol has been carried. If we do this we can compare a nylon strung at 50, which might have an "actual tension" of 40 pounds, with, for example, a poly strung at 60 but, after tension loss, that is now also at an actual tension of 40 pounds. This way, we can compare them both at 40 pounds and get a pretty decent apples to apples comparison of their dynamic stiffness, energy return, deflection, dwell-time, peak force, etc. Then, we can use those actual tensions to compare the nylon at 40 pounds to the same poly at 30 pounds, which might be a good reflection of those strings after they've been played with for 10 hours or so, since we already know that the poly will lose about 10 pounds more tension than the nylon will in real life. Hope that makes sense.

Is looking at the COF of individual strings in a hybrid not pointless? To qoute the TW professor

"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."

I think it's still useful to look at individual strings when plotting a hybrid. If you're going gut/poly, for example, you can look at the hybrids that have been tested, then compare the poly in that hybrid with another poly we might be considering. If the second poly has lower friction in a full bed than the first poly, I think it's reasonable to conclude that that second poly will be more slippery in combination with gut mains than the first one was. The difference might not be that great, but if we're going to obsess about these things and try to find the optimal cross for gut mains it's probably worth looking at. And that's what Jack has done in the OP with his chart showing stiffness and COF numbers for lots of cross string "candidates."

[mikeler]

Originally Posted by corners

No,no, gotta do gut/zx. Have you talked to anyone that's tried gut/n.vy? I thought at one time it would be good but the silicone coating is meant to interface with slippery copoly mains. I would be afraid that the relatively rough gut mains would tear off the coating pretty quick and then all you'd have is a gut/syngut stringbed, which isn't so bad, but you won't get any of that snapback spin. Plus, in that 16x18 the trashed n.vy will cut through the gut fairly quickly.


ZX is 80% less stiff than n.vy and also returns energy better. So it should be more comfortable and more powerful than n.vy. Plus, if the mains are free to slide on the smooth surface of the ZX you'll get the cushion effect that comes with the extra dwell time that accompanies sliding and snapback of the mains, but only if you hit with spin.

You mentioned that the gut/poly you tried felt rather firmer than you expected. Do you typically hit with a lot of spin? On flat shots I find that gut/poly can feel a little firm, but when hitting with spin the feel softens for the reason mentioned above.

Anyway, I've not tried either n.vy or ZX so this is all armchair stuff and might be BS.

My reasoning is this. I cut out a half set of NVy to give to a friend. It somehow disappeared, so all I have left is the other half set. I'd like to try the Monogut as a full bed since it is so expensive. I've also got a half set of Discho Microfibre that I could use.

[corners]

Originally Posted by mikeler

My reasoning is this. I cut out a half set of NVy to give to a friend. It somehow disappeared, so all I have left is the other half set. I'd like to try the Monogut as a full bed since it is so expensive. I've also got a half set of Discho Microfibre that I could use.

Well, if it's between Discho and N.Vy I would go with the N.Vy. I was hoping someone would try N.Vy as a cross. I don't think anyone has done, or at least they haven't reported on it, so you may as well do it

I really liked Gut/Prince Recoil. I thought it functioned very much like gut/copoly but was softer and more powerful. I felt pretty badass off the ground with that setup. I doubt the coating of N.Vy is as slippery or as durable as the PTFE wraps of Recoil, but you should get similar performance for a while, at least, until the silicone coating gets scraped off. Then again, maybe the coating will hang in there.

[mikeler]

Originally Posted by corners

Well, if it's between Discho and N.Vy I would go with the N.Vy. I was hoping someone would try N.Vy as a cross. I don't think anyone has done, or at least they haven't reported on it, so you may as well do it

I really liked Gut/Prince Recoil. I thought it functioned very much like gut/copoly but was softer and more powerful. I felt pretty badass off the ground with that setup. I doubt the coating of N.Vy is as slippery or as durable as the PTFE wraps of Recoil, but you should get similar performance for a while, at least, until the silicone coating gets scraped off. Then again, maybe the coating will hang in there.

NVy it is!

[newyorkstadium]

Originally Posted by corners

In addition, if we're clever we can still use the test data to compare the stiffness and energy return, string deflection and dwell-time, of a poly to a nylon string, or a poly to a natural gut. The String Performance Database allows us to sort results by "actual tension" - the tension is really at after the tension loss protocol has been carried. If we do this we can compare a nylon strung at 50, which might have an "actual tension" of 40 pounds, with, for example, a poly strung at 60 but, after tension loss, that is now also at an actual tension of 40 pounds. This way, we can compare them both at 40 pounds and get a pretty decent apples to apples comparison of their dynamic stiffness, energy return, deflection, dwell-time, peak force, etc. Then, we can use those actual tensions to compare the nylon at 40 pounds to the same poly at 30 pounds, which might be a good reflection of those strings after they've been played with for 10 hours or so, since we already know that the poly will lose about 10 pounds more tension than the nylon will in real life. Hope that makes sense.

I think it's still useful to look at individual strings when plotting a hybrid. If you're going gut/poly, for example, you can look at the hybrids that have been tested, then compare the poly in that hybrid with another poly we might be considering. If the second poly has lower friction in a full bed than the first poly, I think it's reasonable to conclude that that second poly will be more slippery in combination with gut mains than the first one was. The difference might not be that great, but if we're going to obsess about these things and try to find the optimal cross for gut mains it's probably worth looking at. And that's what Jack has done in the OP with his chart showing stiffness and COF numbers for lots of cross string "candidates."

Yeah, that makes perfect sense.

As I've said in a post I started today, a slippery poly cross does not always produce lower COF in a hybrid. With the VS touch, the slippier the poly cross, the higher the COF of the hybrid. Here's the thread- http://tt.tennis-warehouse.com/showt...05#post7273605. The thread title is wrong by the way.

[corners]

Originally Posted by newyorkstadium

Yeah, that makes perfect sense.

When measuring tension loss, I always substitute static tension loss from total tension loss, to get an idea of how much tension the strings lose through playing. Is this erroneous? The impact tension loss has a note saying "some strings (at lower speed impacts) actually are at higher tension after the impact than before". This has made me doubt my method.

Well, they only let the strings site for a little while before they start dropping the hammer on them, so that initial static tension loss might not be that important. But in my opinion you can dig into the numbers as far as you want, you might find something interesting.

Like....

As I've said in a post I started today, a a slippery poly cross does not always produce lower COF in a hybrid. With the VS touch, the slippier the poly cross, the higher the COF of the hybrid.Could you have a look at the thread - http://tt.tennis-warehouse.com/showt...05#post7273605. The thread title is wrong by the way.

...this interesting finding. I'm not sure what to make of this. But certainly it suggests that the COF of the cross is not so important. It might be that the more important thing is that the cross is a poly, which all have hard, smooth, slippery surfaces upon which the mains can glide. But for my money, I'll still choose the more slippery cross over another when plotting my next expensive hybrid experiment. Why not?

As far as that thread, I noticed that the Unwitting Enemies of Science have appeared, so I'll leave that one alone. No use arguing about stuff like that. Some people are more curious than others, some people don't have math backgrounds, etc. No big deal.

[newyorkstadium]

Is there a formula that can be used to work out the stiffness of a hybrid? Since the mains is (supposedly) the 70% dominant string. What about adding the two together then dividing by 2.08?

Originally Posted by corners

Another thing to consider is that all of these stiffness numbers are taken post-tension loss. The nylons lose much less tension than the copolys, so the numbers make the copolys look pretty soft. But I believe TWU's procedure for tension loss measurement is too aggressive. Basically, their tests make the copolys lose more tension than they would in the real world - basically they are testing them "dead" (although I don't believe strings go dead in the way people believe them to). Adjusting for that, the copolys are probably about 10-15% stiffer than they appear in comparison to the nylons.

So the TW test's make the co-polys lose too much tension, but not the nylon strings? If the tests made both lose too much tension, that would be fine. You could still compare strings, it's just the stiffness figures would be a bit off.

Strings have a stabilisation point, so they can't "lose more tension then they would in the real world". This is through the standard tension loss factors though, hitting and at rest, not through the TW method of hitting the stringbed with a hammer.

[polytheist]

String the Nvy crosses higher than the gut. 2 lbs for 16, 3 lbs for 17. 17 is super stretchy.

[newyorkstadium]

bump......

[ChicagoJack]

Originally Posted by newyorkstadium

bump......

Hi newyorkstadium, I really appreciate your thoughtful participation here, it's generated some really awesome dialog lately. However, might I ask you to avoid the bumping routine? I see you do that with smasher08, with the TW Professor, With TravlerAjm, and with StoneAge. Nobody here is under obligation to answer your questions on any particular time frame. Participation here is recreational for most folks, and is squeezed in amongst the pressures of adult life.

Thanks

Jack

[newyorkstadium]

I must admit I'm trying to cram in as much information, as quickly as possible, in my off-season. So i'm thinking about only tennis when I'm back playing.

The question has gone off the first page, so I'm just putting it back on there. As a student, I must admit I do have quite a bit to learn on the pressures of adult life.

[ChicagoJack]

^^
Yeah cool, I totally understand. You are passionately curious, I dig that. I think we both an share obsessive compulsive streak, that fuels the ability to focus in on specific concepts, one at a time until they are understood intimately. The thread has slowly grown into a place free of the typical confrontational under current, which creates a space for real thinking to take place, and this delights me to no end. I'm really glad to have you here.

-Jack

[corners]

Originally Posted by newyorkstadium

Is there a formula that can be used to work out the stiffness of a hybrid? Since the mains is (supposedly) the 70% dominant string. What about adding the two together then dividing by 2.08?

Sure, that sounds reasonable. But only for impacts normal to the stringbed. For glancing blows the mains and crosses are kind of doing different things and this results in longer dwell time and less shock when the mains are free to slide. So this means a lower "effective stringbed stiffness," so to speak.

So the TW test's make the co-polys lose too much tension, but not the nylon strings? If the tests made both lose too much tension, that would be fine. You could still compare strings, it's just the stiffness figures would be a bit off.

Strings have a stabilisation point, so they can't "lose more tension then they would in the real world". This is through the standard tension loss factors though, hitting and at rest, not through the TW method of hitting the stringbed with a hammer.

I don't know about any stabilization point. I don't think there's any such thing. Strings continuously lose tension, they just lose tension faster or slower at different points in their life. But I'm not an expert on that. Could be wrong.

As far as the tension-loss protocol, it appears that nylon strings are much more elastic than copoly, so the force used in the tension-loss part of the testing protocol doesn't lead to unrealistically high loss for nylon, or for natural gut. But copoly strings are different, and the fact that they lose more tension during testing than they seem to in real life is revealing of how different they are from those other materials. But again, even though they seem to lose more tension during testing than in actual play, I think it's still useful to compare the test numbers when looking at poly vs. poly.

[newyorkstadium]

Originally Posted by corners

Sure, that sounds reasonable. But only for impacts normal to the stringbed. For glancing blows the mains and crosses are kind of doing different things and this results in longer dwell time and less shock when the mains are free to slide. So this means a lower "effective stringbed stiffness," so to speak.

What is a glancing blow?

Originally Posted by corners

I don't know about any stabilization point. I don't think there's any such thing. Strings continuously lose tension, they just lose tension faster or slower at different points in their life. But I'm not an expert on that. Could be wrong. As far as the tension-loss protocol, it appears that nylon strings are much more elastic than copoly, so the force used in the tension-loss part of the testing protocol doesn't lead to unrealistically high loss for nylon, or for natural gut. But copoly strings are different, and the fact that they lose more tension during testing than they seem to in real life is revealing of how different they are from those other materials. But again, even though they seem to lose more tension during testing than in actual play, I think it's still useful to compare the test numbers when looking at poly vs. poly.

If you look at this thread, the strings have practically stabilized by the end - http://tt.tennis-warehouse.com/showthread.php?t=398516

[corners]

Originally Posted by newyorkstadium

What is a glancing blow?

I just meant that would produce spin - impacting at angle other than normal to the stringbed.

If you look at this thread, the strings have practically stabilized by the end - http://tt.tennis-warehouse.com/showthread.php?t=398516

I think "practically" is the operative word here. The rate of tension loss diminishes with time, but each time Sten played with the racquet the strings elongated more. My understanding is that the peak force at impact is reduced as strings are reduced in tension. And I believe that it is the force peak that causes plastic deformation, or creep, and elongation of the strings (which reduces the tension further.) So as the tension drops, the impact peak force drops with it, and so the force acting to lengthen the strings is progressively decreased. Thus, the strings lose less tension the looser they are. But each time you impact a copoly string you're going to stretch it beyond its elastic limit, as long as your swing is fast enough. (There might be some exceptions to this, but I don't understand the subject well enough to identify them.)

Here's the tension loss graph from the post you linked to:



So that was Proline II 1.25 after 7 hours of play and a whole bunch of resting time. It lost about 17 pounds, which, from what I've seen is pretty typical of real-world tension loss with lots of polys. By comparison, the TWU numbers for the same string strung at the same tension (51 pounds) was 23 pounds. It's not really that far off, but I think the most important thing to keep in mind is that when looking at the copoly data from TWU is that the numbers represent that string after it has lost about as much tension as it ever will. So if you're comparing a nylon string to a copoly string, both at the same reference tension, you're looking at that copoly essentially at a place in its lifespan that some describe as "dead."

[newyorkstadium]

Will nylon strings continue to lose tension long after the TW tests?

[corners]

Originally Posted by newyorkstadium

Will nylon strings continue to lose tension long after the TW tests? If the nylons tension loss has halted, then it would be best to just use TWU's tension loss figure. If they still have a lot to use, I wonder if it would be best to use rate of loss (total loss minus static loss) to see which string end's up with the highest total tension loss at stabilization point.

In the future, I may test the tension loss of some nylon strings against the TWU data, to see if the nylons are "dead" at the end of TWU's test's

You might want to check out the active thread on TWU's new study about "dead" strings. The TW Professor provides some information that requires us to re-think what "dead" means. He's also written a post that contradicts some of the stuff I've been telling you about tension loss. Believe him, not me.

BTW, what are you after anyway? What's your objective with all these questions about tension loss? Whatever your objective, I think you should post it as a question in a separate thread. ChicagoJack has spent a lot of effort on setting up this thread to answer specific questions about the ideal gut/copoly setup. Your questions are no longer on topic, so it would be good to start a new thread.

[newyorkstadium]

Okay, I will start a new thread. This is an excellent thread by ChicagoJack, and I don't want to veer it off-topic.

[mikeler]

Strung up my Exo Tours last night with Wilson Gut 16/Discho Microfibre 16 at 60 pounds this time. That is 10 pounds above what I had the Wilson Gut at with the Ytex poly hybrid. So we shall see how the gut snaps back now. I know once the Discho gets a little scuffed up that it will get hairy and prevent the snap back but I wanted a real soft string bed as my arm is not quite 100% yet.

[corners]

Originally Posted by mikeler

Strung up my Exo Tours last night with Wilson Gut 16/Discho Microfibre 16 at 60 pounds this time. That is 10 pounds above what I had the Wilson Gut at with the Ytex poly hybrid. So we shall see how the gut snaps back now. I know once the Discho gets a little scuffed up that it will get hairy and prevent the snap back but I wanted a real soft string bed as my arm is not quite 100% yet.

What happened to the slippery N.vy?!