Variance in tension when stringing ahead

Mazilla2219 · 11-09-2009, 09:09 PM

Has anybody else read this (from GGtennis blog):

Tensioning mains: Variance on accepted practices discovered!

According to the United States Racquet Stringer’s Association, it is acceptable to pull tension 2 – 3 ahead on the main strings. Stringer’s who follow this practice regularly are able to achieve CRT and MRT status. While considered acceptable industry practice, we are not convinced this technique creates the most consistent stringbed possible. As a result of this belief we have altered our technique to one where we pull tension on each alternate main as a matter of routine.

With the use of a Stringmeter and ERT we have been testing this premise in our shop. While tensioning mains 2 or 3 ahead before alternating sides we are able to achieve consistent ERT (stringbed stiffness) readings. However, we have discovered that when measuring individual strings with a Stringmeter that an interesting phenomena exists. It seems that parrallel strings (i.e. main #4 on each half of frame) offer identical readings when strings are tensioned using a strict alternating method of tensioning. (Alternating tension on each side going no more than 1 ahead). However, when using a method of pulling tension 2 or 3 ahead the reading on parrallel strings can vary by 3 – 10 pounds! The amount of variance is not consistent, or at least with our limited testing we can not identify a pattern or formula. What we can identify is that a technique consisting of tensioning 2 -3 main strings before alternating sides creates a level of variance that can be measured with a Stringmeter, but does not register on an ERT.

Of course this raises some key questions for stringers. Can players perceive this variance or is it insignificant if the overall stringbed stiffness is consistent? What causes this variance?

Our response to the later, is that this variance could very likely be caused by frame flex. In spite of secure 6 point mounting systems of today’s advanced machines, the racquet will experience some degree of flex while being strung in any machine (with the possible exception of True Tension machines). We hypothesize that the uneven tensioning creates a flex situation that leads to results with undesired variances.

At this point in time we are unclear as to how or if this variance can alter the play of the racquet. What we have been able to do is to identify it as an area that needs additional study. We will need to call on the industry physicists, engineers and the USRSA to explore this further and determine if it is a factor that is or is not important for generating a stringbed that produces ultimate playability.

Until more information is generated, our customers can be assured that all racquets strung by us will be done focusing on the most consistent outcome, even if it extends the time to complete the stringjob by a few minutes.

I usually string 2 ahead and then switch, but this does bring up interesting points. Any other opinions out there?

Bud · 11-09-2009, 09:26 PM

Quote:

Originally Posted by Mazilla2219

Has anybody else read this (from GGtennis blog):

Tensioning mains: Variance on accepted practices discovered!

According to the United States Racquet Stringer’s Association, it is acceptable to pull tension 2 – 3 ahead on the main strings. Stringer’s who follow this practice regularly are able to achieve CRT and MRT status. While considered acceptable industry practice, we are not convinced this technique creates the most consistent stringbed possible. As a result of this belief we have altered our technique to one where we pull tension on each alternate main as a matter of routine.

With the use of a Stringmeter and ERT we have been testing this premise in our shop. While tensioning mains 2 or 3 ahead before alternating sides we are able to achieve consistent ERT (stringbed stiffness) readings. However, we have discovered that when measuring individual strings with a Stringmeter that an interesting phenomena exists. It seems that parrallel strings (i.e. main #4 on each half of frame) offer identical readings when strings are tensioned using a strict alternating method of tensioning. (Alternating tension on each side going no more than 1 ahead). However, when using a method of pulling tension 2 or 3 ahead the reading on parrallel strings can vary by 3 – 10 pounds! The amount of variance is not consistent, or at least with our limited testing we can not identify a pattern or formula. What we can identify is that a technique consisting of tensioning 2 -3 main strings before alternating sides creates a level of variance that can be measured with a Stringmeter, but does not register on an ERT.

Of course this raises some key questions for stringers. Can players perceive this variance or is it insignificant if the overall stringbed stiffness is consistent? What causes this variance?

Our response to the later, is that this variance could very likely be caused by frame flex. In spite of secure 6 point mounting systems of today’s advanced machines, the racquet will experience some degree of flex while being strung in any machine (with the possible exception of True Tension machines). We hypothesize that the uneven tensioning creates a flex situation that leads to results with undesired variances.

At this point in time we are unclear as to how or if this variance can alter the play of the racquet. What we have been able to do is to identify it as an area that needs additional study. We will need to call on the industry physicists, engineers and the USRSA to explore this further and determine if it is a factor that is or is not important for generating a stringbed that produces ultimate playability.

Until more information is generated, our customers can be assured that all racquets strung by us will be done focusing on the most consistent outcome, even if it extends the time to complete the stringjob by a few minutes.

I usually string 2 ahead and then switch, but this does bring up interesting points. Any other opinions out there?

Does this mean that on a racquet with 16 mains... you'll pull tension 8 times on the mains? Am I reading this correctly?

Mazilla2219 · 11-09-2009, 09:30 PM

I don't think that is what it means, you still pull tension 16 times but instead of doing 2 right side mains in a row and then switching to the left side. They are alternating after each side.

TenniseaWilliams · 11-09-2009, 09:54 PM

This is about how many mains you do on each side before switching to the other side. I do two, but start one behind.

For example, I start the mains and do 1L, 1R, 2R, 3R.
Then I switch sides and do 2L, 3L, and 4L.
Then I switch sides and 4R, and 5R.
Switch, 5L and 6L.

This way I can still do two at a time on each side, and never get more than 1 ahead.

Technatic · 11-09-2009, 10:48 PM

I think that every asymmetric load on the racquet during stringing will result in an uneven distribution of the tension and stiffness of the stringbed.

This is easy to understand when you take the limit and tension all strings on one side first before switching to the other side. The racquet will get shorter on the side of the tensioned strings.
When the mains on the other side are tensioned now, the racquet will get longer on the opposite side and the tension in these strings will go up
The result is that the stiffness of the string bed will be higher on that side where you pull tension first.
When you pull tension 3 ahead the effect will be smaller but will still be there.

The reason that the ERT does not measure this is probably because it measures the overall stiffness, because it looks for the natural frequency of the complete stringbed.
It would be interesting to know what it says when you position the tool 2 mains from the middle on each side.

I think that the difference in result will be smaller on a machine with multipoint direct mounting than on a 6-point indirect support. The inwards movement of the racquet will be smaller because the inside supports prevent it from going inwards.
On a 6 point mounting the deflection will be smaller in the position of the supports but bigger in between the 12 and 2 o’clock.

Irvin · 11-15-2009, 04:18 AM

Quote:

Originally Posted by Bud

Does this mean that on a racquet with 16 mains... you'll pull tension 8 times on the mains? Am I reading this correct?

On a racket with 16 mains I will pull tension 17 times. The first pull will be to tension the first right and left mains to set the tension in the clamp. I will set the clamp on the string as far from the tension head as possible inside the frame. Then I pull tension on the string that is not clamped and set the other clamp. Then move to the opposite side and pull tension and clamp two strings and switch back to the other side. I do this until the mains are completed never pulling tension more than one string ahead on either side.

Irvin

jim e · 11-15-2009, 08:58 AM

Quote:

Originally Posted by Irvin

On a racket with 16 mains I will pull tension 17 times. The first pull will be to tension the first right and left mains to set the tension in the clamp. I will set the clamp on the string as far from the tension head as possible inside the frame. Then I pull tension on the string that is not clamped and set the other clamp. Then move to the opposite side and pull tension and clamp two strings and switch back to the other side. I do this until the mains are completed never pulling tension more than one string ahead on either side.

Irvin

Irvin:
I do very similar except for one difference, after I tension and clamp the 1st main, I will tension the next main on the same side, then string the other side, that way I can place the clamps right up to the very inside of the racquet, and this way there is not two strings directly right next to each other trying to clamp both next to each other, and the clamps can both be right up to the inside of the frame.Otherwise there is not sufficient space to place both machine clamps directly next to each other close to the frame directly next to each other as the clamps are too wide.This way when you pull tension on the other side main,there is one string separating the 2 clamps and they can be placed right next to each other.
The USRSA states that it is acceptable to string 3 on one side before alternating.This is only doing 2 , and only the first string.

11-09-2009, 09:09 PM	#1
Mazilla2219 Rookie Join Date: Oct 2008 Posts: 150	Variance in tension when stringing ahead Has anybody else read this (from GGtennis blog): Tensioning mains: Variance on accepted practices discovered! According to the United States Racquet Stringer’s Association, it is acceptable to pull tension 2 – 3 ahead on the main strings. Stringer’s who follow this practice regularly are able to achieve CRT and MRT status. While considered acceptable industry practice, we are not convinced this technique creates the most consistent stringbed possible. As a result of this belief we have altered our technique to one where we pull tension on each alternate main as a matter of routine. With the use of a Stringmeter and ERT we have been testing this premise in our shop. While tensioning mains 2 or 3 ahead before alternating sides we are able to achieve consistent ERT (stringbed stiffness) readings. However, we have discovered that when measuring individual strings with a Stringmeter that an interesting phenomena exists. It seems that parrallel strings (i.e. main #4 on each half of frame) offer identical readings when strings are tensioned using a strict alternating method of tensioning. (Alternating tension on each side going no more than 1 ahead). However, when using a method of pulling tension 2 or 3 ahead the reading on parrallel strings can vary by 3 – 10 pounds! The amount of variance is not consistent, or at least with our limited testing we can not identify a pattern or formula. What we can identify is that a technique consisting of tensioning 2 -3 main strings before alternating sides creates a level of variance that can be measured with a Stringmeter, but does not register on an ERT. Of course this raises some key questions for stringers. Can players perceive this variance or is it insignificant if the overall stringbed stiffness is consistent? What causes this variance? Our response to the later, is that this variance could very likely be caused by frame flex. In spite of secure 6 point mounting systems of today’s advanced machines, the racquet will experience some degree of flex while being strung in any machine (with the possible exception of True Tension machines). We hypothesize that the uneven tensioning creates a flex situation that leads to results with undesired variances. At this point in time we are unclear as to how or if this variance can alter the play of the racquet. What we have been able to do is to identify it as an area that needs additional study. We will need to call on the industry physicists, engineers and the USRSA to explore this further and determine if it is a factor that is or is not important for generating a stringbed that produces ultimate playability. Until more information is generated, our customers can be assured that all racquets strung by us will be done focusing on the most consistent outcome, even if it extends the time to complete the stringjob by a few minutes. I usually string 2 ahead and then switch, but this does bring up interesting points. Any other opinions out there? __________________ 2x Fischer M Pro 98 - (m) MSV hex 1.10 53#/(x) PS Maxim Touch 1.30 58/59# Alpha Revo 4000 - Wise 2086 head

11-09-2009, 09:30 PM	#3
Mazilla2219 Rookie Join Date: Oct 2008 Posts: 150	I don't think that is what it means, you still pull tension 16 times but instead of doing 2 right side mains in a row and then switching to the left side. They are alternating after each side. __________________ 2x Fischer M Pro 98 - (m) MSV hex 1.10 53#/(x) PS Maxim Touch 1.30 58/59# Alpha Revo 4000 - Wise 2086 head

11-09-2009, 10:48 PM	#5
Technatic New User Join Date: Oct 2009 Posts: 37	Asymmetric tensioning I think that every asymmetric load on the racquet during stringing will result in an uneven distribution of the tension and stiffness of the stringbed. This is easy to understand when you take the limit and tension all strings on one side first before switching to the other side. The racquet will get shorter on the side of the tensioned strings. When the mains on the other side are tensioned now, the racquet will get longer on the opposite side and the tension in these strings will go up The result is that the stiffness of the string bed will be higher on that side where you pull tension first. When you pull tension 3 ahead the effect will be smaller but will still be there. The reason that the ERT does not measure this is probably because it measures the overall stiffness, because it looks for the natural frequency of the complete stringbed. It would be interesting to know what it says when you position the tool 2 mains from the middle on each side. I think that the difference in result will be smaller on a machine with multipoint direct mounting than on a 6-point indirect support. The inwards movement of the racquet will be smaller because the inside supports prevent it from going inwards. On a 6 point mounting the deflection will be smaller in the position of the supports but bigger in between the 12 and 2 o’clock.

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