# Proportional Stringing

#### Dags

##### Hall of Fame
Pretty sure this whole thread has become one big advertisement. Irvin sounds more and more like a shill for Sergetti with each post.

#### MathieuR

##### Professional
Gee, this sounds like another ad for Stringway..
You are right. I edited the post, I added:
or any other device that allows you to measure DT on different spots of the stringbed.

#### Imago

##### Hall of Fame
I'm dont think @Peter Masters likes to hear me say this but when I think of a sweet spot it is just that a spot on the racket.Think of of single string strung under tension between two points. The spot in the center is the easiest point to deflect a specific distance with a given force. If that string is deflected with the same force at any other point closer to the suspension points the string will not deflect as much. Dynamic Tension is a measure of the force required in Kg to deflect the Stringbed one cm. and a stringbed can be looked at just like that string except that the stringbed has two dimensions height and width and not just one like the single string has.

So now lets look at a string bed. The spot in the center of the frame is the spot on a string bed that is still going to be the easiest to deflect if all the string are tensioned at the same tension or if the string are strung proportional to their length. As you go out from that point in any direction DT will go up because that is the sweet SPOT. There is another point on the frame the Center Of Percussion (COP) which is found by the formula COP = M/SW*balance. The COP is usually just above the sweet spot where most people hit the ball but the DT at the COP will be higher than the DT at the sweet spot. Then there is the bottom of the racket. The lower I go down on the string bed to hit the ball the closer the impact point is to the COM. That why a racket will have more power in the lower portion of the string bed. The only reason you can apply as much force to the ball hiting in the lower portion of the string bed is because the contact point is not traveling as fast. That pretty much covers the centerline of the string bed but what happens when you hit off the centerline?

If you contact the ball off the center two mains the hit will feel harsher and harsher because the string bed is stiffer and you're farther away from the COM. IMO the only way to adjust your racket for that is to make the string bed softer or add weight specifically to increase Twist Weight. In the traditional way to string a racket you can lower the tension to increase the size of the sweet spot. I believe that is rubbish the size of the spot does not change and lowering the tension lowers the DT at the Sweet Spot the ball sits on the strings longer and you loose control. By stringing proportionally dropping the tension at you get farther and farther from the sweet spot you can equalize the DT across the string bed. It is always going to go up as you go out but the difference will not be as great. Assume you string a racket proportionally and in the center the four intersecting string (2 mains and 2 crosses) are strung at 60 lbs. it takes a given force to deflect the strings given distance. If you go to the up 4 stings and to the left 4 strings the same force will not deflect the strings as much. So what can be done to make that point closer to the sweet spot? Drop the tension of course. The DT will still be higher but it feels closer to the DT at the sweet spot. THe vibration will still be harsher because it is farther from the COP. You still have the fell of a bad shot but not as bad.

You can do what @Imago is doing and play around with you own proportional stringing method. He has strung a few racket with Gut/poly now and he says he has found the best frame he has ever played with. A few sets of gut/poly cost more than the Sergetti system and if you don't get lucky like @Imago and find just the right tensions you wasted a few sets of gut/poly.
First three paragraphs have paramount importance. I cannot enough thank you for them.

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#### Irvin

##### Talk Tennis Guru
First three paragraphs have paramount importance. I cannot enough tank you for them.
Well TANK you too. LOL

#### Irvin

##### Talk Tennis Guru
I'll take a look it later when I find out how to translate it.

#### Rabbit

##### G.O.A.T.
Update: I played tonight with my Sergetti strung Pro 1. I don't know if I was having a good night, if thinking that the string job was "special", or if I've gotten used to my new frame but I played great. The single biggest change was my backhand which was really dialed in. The string bed is "tamer" if that makes any sense, more predictable. It just seemed like I got an even response on most every shot. Some have reported a drop off in spin, I didn't experience that, to the contrary, I found even more spin tonight.

So far, so good. I'm going to string my other Pro 1 Sergetti-style.

Edit: BTW I'm using synthetic gut 1.25 at 54

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#### Tordne

##### Semi-Pro
Purchased three more Sergetti sheets this morning

#### Rabbit

##### G.O.A.T.
Played again tonight, this time on clay. I don't understand it and can't believe it, but it does appear to make a difference. I had another really good outing. The string bed feels uniform and control is really good. Comfort is there as well.

#### Tordne

##### Semi-Pro
Played again tonight, this time on clay. I don't understand it and can't believe it, but it does appear to make a difference. I had another really good outing. The string bed feels uniform and control is really good. Comfort is there as well.
This is perhaps what I’ve been most of 7 of 8 days in a row and my arm feels totally fine. Previously I would have felt my arm being a bit tight after each of these sessions. There are a few ladies around our club with those tennis elbow braces on. Not withstanding a lot are using a terrible racket for their injury and style of play, I wonder how much the a Sergetti stringing could positively contribute?

#### Irvin

##### Talk Tennis Guru
@Peter Masters, Probably a silly question, but strung a racket for a customer this morning who likes power pads. Should the use of leather power pads in the throat grommets change the tension recommendation for those strings.

#### Peter Masters

##### New User
@Peter Masters, Probably a silly question, but strung a racket for a customer this morning who likes power pads. Should the use of leather power pads in the throat grommets change the tension recommendation for those strings.
Will check for you as I am not sure.

#### Peter Masters

##### New User
Will check for you as I am not sure.
I checked with HQ, the use of leather pads will not require any change to any of the SERGETTI tensions from the PTS

#### Imago

##### Hall of Fame
If this is a thread dedicated to Sergetti stringing, please change correspondingly the topic because it became clear that Sergetti stringing is not proportional stringing. Some colleagues may be led astray to think that proportional is a synonym for Sergetti. So I am asking the OP or the moderators to change the topic to SO-STAB STRINGING or whatever @Peter Masters finds to be an appropriate and adaequate name for their stringing.

#### afeller

##### New User
I've also tested the Sergetti stringing with my Head Microgel Prestige MP with MSV Focus-HEX Soft at 22 kg. Its really remarkable, that the racket came out of the turntable without ANY force.

Yesterday i played with this racket and it feels very good. Wherever i hit the ball the feeling was the same and it was a good feeling.

Disadvantage: I cannot feel, where i hit the ball on the racket. On a normal string job you can feel it when you hit on the outside of the stringbed. Don't know if its good for training, when you don't know where you hit the ball on the stringbed.

#### Irvin

##### Talk Tennis Guru
If this is a thread dedicated to Sergetti stringing, please change correspondingly the topic because it became clear that Sergetti stringing is not proportional stringing. Some colleagues may be led astray to think that proportional is a synonym for Sergetti. So I am asking the OP or the moderators to change the topic to SO-STAB STRINGING or whatever @Peter Masters finds to be an appropriate and adaequate name for their stringing.
I think you're wrong

#### Irvin

##### Talk Tennis Guru
I cannot feel, where i hit the ball on the racket. On a normal string job you can feel it when you hit on the outside of the stringbed. Don't know if its good for training, when you don't know where you hit the ball on the stringbed.
I don't get that sensation when I hit off center I do feel it.

#### Imago

##### Hall of Fame
I think you're wrong
So you think it's proportional stringing par excellence.

#### Irvin

##### Talk Tennis Guru
So you think it's proportional stringing par excellence.
Absolutely, I've not encountered any better. In the past all tension has been adjust solely on the length of the string. The Sergetti method using a lot more to determine the tensions that should be applied to the string but I'd still consider it proportional.

#### Karma Tennis

##### Hall of Fame
OK. So what we need now is for an Electronic CP Tension Head manufacturer to implement a software app and hardware interface to allow the tension settings for each each string to be programmed prior to each string job. That way, the stringer doesn't have to keep adjusting tensions manually between pulls, the software will automate the process.

#### Rabbit

##### G.O.A.T.
@Karma Tennis - it's really no big deal to do. After I play through these two string jobs, I'm going to restring normally and see if there's a difference.

#### Imago

##### Hall of Fame
OK. So what we need now is for an Electronic CP Tension Head manufacturer to implement a software app and hardware interface to allow the tension settings for each each string to be programmed prior to each string job.
This would be an entirely new electronic head, much more sophisticated than Wise and almost impossible to program as you have to enter between 20 and 50 parameters and be always connected to an ever growing online database maintained by a community of stringers.

#### Rabbit

##### G.O.A.T.
Update: So I broke strings in one of the Sergetti strung frames and restrung it as mentioned above normal style. I have to say that while I was enthused to begin with, there really is no difference, certainly not a difference worth paying for. I did not find the Sergetti strung frame to display any extraordinary characteristics in comparison to the conventionally strung frame. IMO, the conventionally strung frame felt more solid off the ground.

It was worth trying, but in the end I cannot recommend shelling out \$'s for this. I think any perceived difference is between the ears and folks subject to "tinkering" will think it's the cat's meow.

#### MathieuR

##### Professional
I think any perceived difference is between the ears and folks subject to "tinkering" will think it's the cat's meow.
I think "in general" a larger, uniform sweetspot must feel "better".

It's a pitty the difference with a "normal" strung racket can not be measured by most.

#### Rabbit

##### G.O.A.T.
I think "in general" a larger, uniform sweetspot must feel "better".
I would agree, I just don't happen to feel that this produces it.

It's a pitty the difference with a "normal" strung racket can not be measured by most.
I would think it would even be a "pity". When you say "measured by most" pray tell whatsoever do you mean?

#### MathieuR

##### Professional
pray tell whatsoever do you mean?
It is a pity that most (all?) users of the S-system can not measure the ( increase of) size from the sweetspot, only can use racquettune for a "general impression".

#### Rabbit

##### G.O.A.T.
It is a pity that most (all?) users of the S-system can not measure the ( increase of) size from the sweetspot, only can use racquettune for a "general impression".
Sorry, I don't use racquettune. I have an ERT 300 which I rely on.

#### 4-string

##### Professional
Cue, Stringlab plug.

#### MathieuR

##### Professional
. I have an ERT 300 which I rely on.
Exact same thing: a frequency is transformed into a DT with an algorithm

#### Rabbit

##### G.O.A.T.
Exact same thing: a frequency is transformed into a DT with an algorithm
Not exactly as there are quite a few more variables with racquettune. I have both & find the ERT to be much more repeatable.

#### MathieuR

##### Professional
I have both & find the ERT to be much more repeatable.
Both RT and the ERT "transform" a measured frequency into DT.

These are both indirect measurements.

A key-factor is the weight of the vibrating system. With RT this is only the stringbed, with the ERT this is stringbed + ERT.
As the weight of the ERT "dominates", the stringbed-weight-variations have hardly any influence.

#### Rabbit

##### G.O.A.T.
Both RT and the ERT "transform" a measured frequency into DT.

These are both indirect measurements.

A key-factor is the weight of the vibrating system. With RT this is only the stringbed, with the ERT this is stringbed + ERT.
As the weight of the ERT "dominates", the stringbed-weight-variations have hardly any influence.
Yeah, whatever. I'll stick with the ERT.

Have you ever noticed that you consistently argue with each and everybody on the boards about nothing but minutia? If it was just me, ok, but everybody?

I'd like to introduce you to a fence post.

#### MathieuR

##### Professional
Have you ever noticed that you consistently argue with each and everybody on the boards about nothing but minutia? If it was just me, ok, but everybody?
No, I don't think measuring the DT accurately can be considered as "minutia". Every stringer with some self-respect measures the result of his string-job. And I do think that a lot of users of an ERT don't realize that this nice gadget measures by frequency-measurement. Why do you think a Babolat RDC uses a indentation method?

#### hopcio

##### New User
Hi guys, I'm trying out the sergetti method right now, for me is more a matter of tension maintenance. I got back to the game and one of the frustrating things about polys in my opinion is that they loose tension really fast ... if this solve the problem then I'm all in with it ... so far I've been playing 5 hours with it, first 2 adjustment period, felt different actually, after the 3 hour felt pretty good, even my shoulder appreciates it. By this time a normal stringing method will start to feel that I need to change it. So let's see how it continues to go

Sent from my iPhone using Tapatalk

#### Karma Tennis

##### Hall of Fame
Every stringer with some self-respect measures the result of his string-job.
Indeed. And the best way to measure the result of any string-job is via direct feedback from the user (ie. the player who uses the racquet.) AFTER they have used the racquet. Any other measurement devices simply provides a "guesstimate".

The same can be applied to any special stringing process. The ultimate measure of success lies in the hands (or is that mind?) of the user.

#### Irvin

##### Talk Tennis Guru
@Rabbit did you ever revert back to the conventional method yet?

#### Rabbit

##### G.O.A.T.
No, I don't think measuring the DT accurately can be considered as "minutia". Every stringer with some self-respect measures the result of his string-job. And I do think that a lot of users of an ERT don't realize that this nice gadget measures by frequency-measurement. Why do you think a Babolat RDC uses a indentation method?
And he continues to argue....

racquettune has many more external variables.

1. The microphone in the device being used to "listen"
2. The distance between the microphone and the string bed
3. The object being used to generate the frequency; i.e. pen, pencil, awl, etc
4. Background noise
IMO all are fairly dynamic and are extremely likely to interfere with or skew results. Hey, I bought racquettune and the other tool. I also have an ERT 300 have you used both?

#### Rabbit

##### G.O.A.T.
@Rabbit did you ever revert back to the conventional method yet?
Update: So I broke strings in one of the Sergetti strung frames and restrung it as mentioned above normal style. I have to say that while I was enthused to begin with, there really is no difference, certainly not a difference worth paying for. I did not find the Sergetti strung frame to display any extraordinary characteristics in comparison to the conventionally strung frame. IMO, the conventionally strung frame felt more solid off the ground.

It was worth trying, but in the end I cannot recommend shelling out \$'s for this. I think any perceived difference is between the ears and folks subject to "tinkering" will think it's the cat's meow.

Yes, per my earlier post.

#### MathieuR

##### Professional
And the best way to measure the result of any string-job is via direct feedback from the user (ie. the player who uses the racquet.) AFTER they have used the racquet. Any other measurement devices simply provides a "guesstimate".
Its both: what you call the "guesstimates-value", in combination with user-experience
(+ used ref.tensions + string-type). This way you know what guesstimates-value is fit for a certain client.

#### Rabbit

##### G.O.A.T.
Indeed. And the best way to measure the result of any string-job is via direct feedback from the user (ie. the player who uses the racquet.) AFTER they have used the racquet. Any other measurement devices simply provides a "guesstimate".

The same can be applied to any special stringing process. The ultimate measure of success lies in the hands (or is that mind?) of the user.
True the above. There have been quite a few guys who were first timers with me. They either tell me a tension or don't. If they do, I string it at that tension. If they don't, I'll ask them if they like tight or loose. In either case, the first time if they don't like it, I ask for feedback....tighter, looser? I make the adjustment and give them a free restring. Works wonders for them and is just fair play. 99.9% of them wouldn't know dynamic tension or string bed stiffness if it bit them on the arsecicle.

#### esgee48

##### Legend
I'm with you. Most of my clients are repeats and they like a specific tension. A new one gets questioned, but basically, tight or loose, poly or SG. At least with RT, you can now get a handle on the tension in their frame because most of them do not know nor care. Most err for tighter since they know strings lose tension.

#### kkm

##### Professional
RDC and Stringlab 2 will change the SBS because they actually deflect the stringbed.

#### MathieuR

##### Professional
RDC and Stringlab 2 will change the SBS because they actually deflect the stringbed.
Yeah , and when all people in NY walk west at the same moment, the earth starts to rotate faster.

#### Imago

##### Hall of Fame
When you string proportionally (not Sergetti) poly/multi, the multi strings go down by almost 10 lbs after stringing and the mains start to move like hell. I have to compensate the crosses at least by 5 kg up to get something decent, which makes all proportionality... useless/ridiculous/redundant/funny (choose the proper word).

#### Karma Tennis

##### Hall of Fame
Yeah , and when all people in NY walk west at the same moment, the earth starts to rotate faster.
Ah! So if we can convince them all to walk East at the same moment, the Earth will proceed to rotate at a slower rate.

More hours each day to play tennis, or even restring racquets

#### MathieuR

##### Professional
the multi strings go down by almost 10 lbs after stringing
After doing only the mains, the head is compressed ~2-3mm. A "average" string has a elastic elongation at 25kg of 2% that holds the tension, on 350mm = 7mm. So, every mm = ~3.6kg. 2-3mm compression --> 7.2-10.8kg tension-loss (which is recovered after finishing the crosses at proper tension).

#### Imago

##### Hall of Fame
After doing only the mains, the head is compressed ~2-3mm.
Only if the holding posts and towers are released. Otherwise the frame is not being deformed. The only real deformation occurs when stringing the crosses.

#### MathieuR

##### Professional
Only if the holding posts and towers are released. Otherwise the frame is not being deformed. The only real deformation occurs when stringing the crosses.
Sorry to disapoint you, but even from the most expensive Babolat the towers will bend if you string the mains.
Realize that when 16 mains are strung at 25kg, the towers experience a force of 400kg.

Just measure it at your system

#### MathieuR

##### Professional
Hey, I bought racquettune and the other tool. I also have an ERT 300 have you used both?
I did use RT on my android. Installed it again ("it" did know I did pay last time, cause it was free now). Nice gadget.
I bought some stuff from a stringer that did stop stringing: a 30 year old glidebar-Stringway, strings etc ánd an ERT-700 in good working order.
I already have my Stringlab2 and a stringmeter. I will do some parallel measurements.