Seriously — testing poly for elasticity loss

Many say that one should cut polys after 8-12 hours of play but that is a quite arbitrary and uncertain measure because it is highly dependent on the intensity of play and weather conditions (temperature). It is really about elasticity loss due to repeated stretching of the poly string.

When I play and practice singles with bigger hitters, polys definitely die out much more rapidly. I can clearly feel the loss of responsiveness.

Playing doubles, with 3.0/3.5 rec. players and in mild weather makes polys last longer.

In either cases, it also depends on the exact poly composition.

With all this said — does anyone have any more reliable way to measure the elasticity loss — without buying a multi-$K Babolat RDC machine or counting some arbitrary hours or waiting to “feel it in the arm”?

Tourna Stringmeter and similar don’t measure elasticity loss.
 

esgee48

G.O.A.T.
A lot of the bigger hitting clients I have use either ALU/RPM Blast of just plain old 4G. In the former cases, they accept the limited number of hours cuz ALU and RPM Blast are the best feeling for them for up to 6 hours. Many have multiple frames so they don't care. I am the poor smuck stuck with restringing them. Many of these folks have gone the 4G route cuz the string is factory prestretched to remove losses asssociated with elongation. At a certain point, unless you are a pro, you can't hit the ball hard enough to have noticeable tension losses cuz the string has been prestretched (work hardened). At this point the bed performs relatively the same until it breaks or there is no more snapback due to notching. If you go thru the effort of manually prestretching plain old 1st gen polys, eg 8-12"/20' section, you can basically have the same effect. Of course the stiffness rating is very high, so you basically use low(er) ref tensions suitable for the player and frame and the 1.30mm is almost 1.26-1.27mm. @Shroud and @travlerajm do this to have usable poly string lives.
 

Shroud

Talk Tennis Guru
A lot of the bigger hitting clients I have use either ALU/RPM Blast of just plain old 4G. In the former cases, they accept the limited number of hours cuz ALU and RPM Blast are the best feeling for them for up to 6 hours. Many have multiple frames so they don't care. I am the poor smuck stuck with restringing them. Many of these folks have gone the 4G route cuz the string is factory prestretched to remove losses asssociated with elongation. At a certain point, unless you are a pro, you can't hit the ball hard enough to have noticeable tension losses cuz the string has been prestretched (work hardened). At this point the bed performs relatively the same until it breaks or there is no more snapback due to notching. If you go thru the effort of manually prestretching plain old 1st gen polys, eg 8-12"/20' section, you can basically have the same effect. Of course the stiffness rating is very high, so you basically use low(er) ref tensions suitable for the player and frame and the 1.30mm is almost 1.26-1.27mm. @Shroud and @travlerajm do this to have usable poly string lives.
FWIW I use 4g as a cross and ALWAYS manually prestretch it pulling on one end and leaning with my body, because they didn't do enough at the factory...
 

Shroud

Talk Tennis Guru
Many say that one should cut polys after 8-12 hours of play but that is a quite arbitrary and uncertain measure because it is highly dependent on the intensity of play and weather conditions (temperature). It is really about elasticity loss due to repeated stretching of the poly string.

When I play and practice singles with bigger hitters, polys definitely die out much more rapidly. I can clearly feel the loss of responsiveness.

Playing doubles, with 3.0/3.5 rec. players and in mild weather makes polys last longer.

In either cases, it also depends on the exact poly composition.

With all this said — does anyone have any more reliable way to measure the elasticity loss — without buying a multi-$K Babolat RDC machine or counting some arbitrary hours or waiting to “feel it in the arm”?

Tourna Stringmeter and similar don’t measure elasticity loss.
Doesn't the ERT300 measure that in a way?
 

EggSalad

Hall of Fame
If you experience loss of control or any discomfort, cut it out. Trust your own senses.
Yeah, it’s pretty obvious to me when a poly has lost its elasticity or is ready to be cut it. I don’t even keep really close track of the hours. Just a rough estimate and feel is what tells me it’s time.
 

ryohazuki222

Hall of Fame
Many say that one should cut polys after 8-12 hours of play but that is a quite arbitrary and uncertain measure because it is highly dependent on the intensity of play and weather conditions (temperature). It is really about elasticity loss due to repeated stretching of the poly string.

When I play and practice singles with bigger hitters, polys definitely die out much more rapidly. I can clearly feel the loss of responsiveness.

Playing doubles, with 3.0/3.5 rec. players and in mild weather makes polys last longer.

In either cases, it also depends on the exact poly composition.

With all this said — does anyone have any more reliable way to measure the elasticity loss — without buying a multi-$K Babolat RDC machine or counting some arbitrary hours or waiting to “feel it in the arm”?

Tourna Stringmeter and similar don’t measure elasticity loss.
Ert 300 is good enough. It doesn’t doesn’t measure elasticity lost but it kind of does ish sorta kinda. At least it’s better than hours on court.

Short version:
- if I string a racket at 50 pounds reference tension I will have stretched that string a certain amount and tied off the ends and have it in a racket.

- now if I keep smacking that string against a ball really hard over and over it’ll keep stretching and stretching on impact but it’s still occupying the same amount of space in the racket. So some slack gets created and tension in the stringbed drops.

Technically; this isn’t necessarily loss of elasticity; but it is a different metric than “hours” that in my experience is more accurate.

If you always measure ert 300 off the stringer; and then again before the first hit. And then again after you decide you’re tired of “dead” strings…. What I’ve found is it’s repeatable and consistent to within 1-2 DT from measurement.

Interestingly; to your point; I’ll lose tension and playability faster if I’m player competitive sets —- fairly certain it’s from smacking serves over and over again…. Compared to just generally hitting.
 

Irvin

Talk Tennis Guru
Of course. My question though is — is there a more reliable way to measure elasticity loss, at home and without expensive equipment?
If I understand it correctly there is not elasticity loss. Poly string can be plastically deformed by stretching. And the more the string is stretched, and the more the string is subjected to extreme temperatures, the more the string is plastically deformed or stretched. Elasticity is a strings ability to return to its normal length and the more the string is plastically deformed the longer the normal length with no tension the lower the tension will be. But the elasticity is still there, it’s just the the different between the longer normal length is closer to the stretched length so there is less tension stored in the string.

I don’t know Of a way to test the plasticity and elasticity in a string but you can test tension. There are some expensive ways to do it and some lower cost ways. The ERT is one way but they’re not low cost. You could get a gamma string tension tester or a Tourna stringmeter. Those two units work on string deflection to measure tension. Not sure how accurate they are but they work. There is also an app called RacquetTune that measure a string bed’s frequency. Tension in the string bed causes the string to vibrate at a specific frequency. The lower the frequency the lower the tension. The higher the frequency the higher the tension. String two rackets at the same tension and play with one and you will find the if you tap the rackets on each other you can hear a difference because the played racket will have a lower frequency.

My suggestion would be to check out RacquetTune the cost is quite reasonable.
 

10sbeast888

Hall of Fame
for 3.0/3.5 recs I can specifically recommend GoldenSet Power Cord... used this for 10+ years never need to cut, recommended to many rec friends, never any arm issue.... string between 25-50 lbs to your liking.

this thing is so soft.... it is definitely softer than some nylon like OG micro.
 
My suggestion would be to check out RacquetTune the cost is quite reasonable.
Thanks for your suggestion. I have it and used it some, but I was not 100% sure if it is reliable.

Do you have any recommendations for using Racquet Tune to measure when it is time to replace the poly?

P.S. I watched many of your videos and learned many stringing tips and tricks from you. Thank you for that.
 

Irvin

Talk Tennis Guru
Thanks for your suggestion. I have it and used it some, but I was not 100% sure if it is reliable.

Do you have any recommendations for using Racquet Tune to measure when it is time to replace the poly?

P.S. I watched many of your videos and learned many stringing tips and tricks from you. Thank you for that.
I’m not sure any of those gizmos are that reliable. but They give you a good idea of what‘s happening. If you want to use something like RT just use it in conjunction with how you feel the rackets is playing. When you save readings you can add a short comment and time played. I pretty much only measured only by frequency when I was using it. Frequency is what is used to convert to something else like tension or DT. I always felt converting to something else with string factors just introduced error.
 
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