Sergetti Stringing - WOW!

Rabbit

G.O.A.T.
The frames all these players used were 30% heavier than those used currently - which makes a huge difference in terms of mass and vibration.


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Another big difference with a pro player and us regular guys is timing. Pros have perfect timing and can use equipment that is on the edge. We can't.
 

Karma Tennis

Hall of Fame
The frames all these players used were 30% heavier than those used currently - which makes a huge difference in terms of mass and vibration.
If it was that simple, then any player that complains that their racquet is too stiff (eg. a lot of Pure Drive users.) simply had to add a whole heap of weight to their frames. Voila, all their problems will disappear and they won't need to resort to odd stringing methods to make their racquets more "comfortable".

Another big difference with a pro player and us regular guys is timing. Pros have perfect timing and can use equipment that is on the edge. We can't.
And that is the main reason for everything.
 

The Big Kahuna

Hall of Fame
Strung my racket with the Sergetti Method about three weeks ago with a poly/synthetic gut hybrid to see what the fuss is about. The longer I play with it the better it feels. This is translating directly to improved results on the court. Control, feel, spin, power, and sweet spot all are much improved.

I think I’m sold.


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gazz1

Semi-Pro
Strung my racket with the Sergetti Method about three weeks ago with a poly/synthetic gut hybrid to see what the fuss is about. The longer I play with it the better it feels. This is translating directly to improved results on the court. Control, feel, spin, power, and sweet spot all are much improved.

I think I’m sold.


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That's great news...your a higher level player than me so it's good to see that it also helps people who are not hitting off centre most of the time :)

Just out of curiosity, did you find it played a little stiffer initially?
 

The Big Kahuna

Hall of Fame
That's great news...your a higher level player than me so it's good to see that it also helps people who are not hitting off centre most of the time :)

Just out of curiosity, did you find it played a little stiffer initially?
Actually, no. The increased size of the sweet spot gave me the sensation of a slightly softer stringbed. That said, I know some say the opposite. Regardless, it seems to even out and settle in after an hour or two.


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jmc3367

Rookie
I just strung my Prince textream tour 95 with this method using tier 1 firewire boost. I will play with it tomorrow and Saturday and will give my report as well. Just FYI I string a 50# cross and Main. Some of the string tensions seemed kinda strange to me but I did it the way they said. Another note I do string on a neos lockout machine so I pulled each tension 3 times to try and make up for the constant pull of a electronic machine
 

speedysteve

Legend
I just strung my Prince textream tour 95 with this method using tier 1 firewire boost. I will play with it tomorrow and Saturday and will give my report as well. Just FYI I string a 50# cross and Main. Some of the string tensions seemed kinda strange to me but I did it the way they said. Another note I do string on a neos lockout machine so I pulled each tension 3 times to try and make up for the constant pull of a electronic machine
Yes, I've found it I double pull to pre-stretch on my lock out machine I get higher final tensions.
 

jmc3367

Rookie
Last night I played with my Textreme tour 95 strung with the Sergetti method at 50# on a lock out Prince neos which I triple pulled to simulate as close a possible to a electronic constant pull machine. The result is this. It was definitely not a wow moment. Considering some of the crazy (IMHO) tensions it did not play as loose as I thought it would. I am going to play with it again Saturday and see how it has settled before I really decide if I like it or not. If I had to make a decision at this moment I would say don't waste your money at least on this racket. The effect could be much better on a larger headed racket. that's my 2 cents.
 

tennisbike

Semi-Pro
Does anyone own Stringmeter and has a racket strung with proportional stringing?
I would love to see what the SM reading on all the mains and cross strings look like.

Thanks.
 

Irvin

Talk Tennis Guru
Does anyone own Stringmeter and has a racket strung with proportional stringing?
I would love to see what the SM reading on all the mains and cross strings look like.

Thanks.
The next time I string mine I can measure them for you, but not with Sergetti but my proportional stringing pattern. I’ll let my reference tension and measured tensions after stringing.
 

TennisCJC

Legend
Afaik, Borg played with Natural Gut.

Sampras played with early incarnations of monofilament Polyester string which are a lot stiffer than modern poly and copoly strings.

Agassi played with Kevlar strings which I understand are also a lot stiffer than modern copoly strings.

They did not have major arm issues because the frames they were using were much softer than the majority of modern frames available today. (Borg used wooden frames. Sampras and Agassi used frames that had RDC ratings in the high 40s to low 50s IIRC.)
I think Agassi had a pretty significant wrist injury and possibly (?) surgery. He strung Kevlar and later poly at pretty high tensions and I think he paid the price.

I don't think Sampras used poly while playing. He uses poly on legends tour but I think he stuck with all gut at very high tensions (75 lbs roughly) during his ATP tour days. His racket while on tour was 85" head so gut at 75 lbs would play very firm. On legends, he is using a bigger head and poly and I have no idea of tension but assume he dropped it way down from 75 lbs.

Borg played natural gut in a wood frame at very high tensions (roughly 80 lbs). I don't recall any significant elbow or arm injuries for Borg but he was using a softer and heavier racket, playing against slower pace and retired at 26.

I also doubt if Agassi and Sampras had RDC in low 50s or lower. The 85" pro staff used by Sampras was a reasonable firm racket. I am not sure about the Princes, Donnays or Head Radicals used by Agassi. My guess is Agassi's radicals were relatively soft in the high 50s RDC range. Sampras' pro staff was also likely high 50s or above. Borg's Donnay wooden frames were considered stiff for the day but certainly more flexible than most any graphite composite.
 

The Big Kahuna

Hall of Fame
Last night I played with my Textreme tour 95 strung with the Sergetti method at 50# on a lock out Prince neos which I triple pulled to simulate as close a possible to a electronic constant pull machine. The result is this. It was definitely not a wow moment. Considering some of the crazy (IMHO) tensions it did not play as loose as I thought it would. I am going to play with it again Saturday and see how it has settled before I really decide if I like it or not. If I had to make a decision at this moment I would say don't waste your money at least on this racket. The effect could be much better on a larger headed racket. that's my 2 cents.
As this stringing method favors higher tensions in the longest strings - which loosen up the most over time - I found that this stringing system played best after those long strings loosened up a bit so as to give a more uniform tension over the entire string bed. In short, give it 2-3 hours and let me know what you think then.


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The Big Kahuna

Hall of Fame
I think Agassi had a pretty significant wrist injury and possibly (?) surgery. He strung Kevlar and later poly at pretty high tensions and I think he paid the price.

I don't think Sampras used poly while playing. He uses poly on legends tour but I think he stuck with all gut at very high tensions (75 lbs roughly) during his ATP tour days. His racket while on tour was 85" head so gut at 75 lbs would play very firm. On legends, he is using a bigger head and poly and I have no idea of tension but assume he dropped it way down from 75 lbs.

Borg played natural gut in a wood frame at very high tensions (roughly 80 lbs). I don't recall any significant elbow or arm injuries for Borg but he was using a softer and heavier racket, playing against slower pace and retired at 26.

I also doubt if Agassi and Sampras had RDC in low 50s or lower. The 85" pro staff used by Sampras was a reasonable firm racket. I am not sure about the Princes, Donnays or Head Radicals used by Agassi. My guess is Agassi's radicals were relatively soft in the high 50s RDC range. Sampras' pro staff was also likely high 50s or above. Borg's Donnay wooden frames were considered stiff for the day but certainly more flexible than most any graphite composite.
Borg and Sampras played with NATURAL GUT - a much more elastic string than Kevlar or Poly. They also played with very HEAVY and very FLEXIBLE graphite racquets (at least after 1984). See the difference?


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jmc3367

Rookie
As this stringing method favors higher tensions in the longest strings - which loosen up the most over time - I found that this stringing system played best after those long strings loosened up a bit so as to give a more uniform tension over the entire string bed. In short, give it 2-3 hours and let me know what you think then.

You are absolutely correct. the racket plays much much better now and I have about 3-4 hours on it. I still Can't say it's a huge difference than traditional stringing but It does seem to be getting better. I would say it feels a bit softer over all. I will continue to use the method over a period of time and see how it goes.

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scf

Semi-Pro
Just found that sergetti's order form now allows to enter different tension for mains and crosses and also offers discounts when buying several sheets.
 

The Big Kahuna

Hall of Fame
Just found that sergetti's order form now allows to enter different tension for mains and crosses and also offers discounts when buying several sheets.
Yes. I have done this. They are very accommodating.

You can also get the same effect of having different attention is for the main screens and cross strings by simply averaging the string tension I have found, as well.


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AndI

Rookie
Does anyone own Stringmeter and has a racket strung with proportional stringing?
I would love to see what the SM reading on all the mains and cross strings look like.
I'll second this request. I am curious to see the numbers. My son did a similar thing for his middle school science project, it took him close to 3 hours to map a racquet with ERT-300 - which translated into 18 hours of mapping in total, for one reference and five proportional stringing methods. That, however, required mapping of every cross on the racquet, I think about 240 measurements or so. It was a fun project, and he earned first place in his category in Pacific Northwest Science Fair. With Stringmeter, we are talking about only 35 readings or so - should be much faster! But one also needs a reference measurement to compare.

@Andl , an ERT300 can not be used to measure DT distribution on a stringbed.
The only realistic option is measurement of the deflection when using a force on every spot.
Of course it can be used! Why not? ERT-300 measures resonance frequency of the stringbed at the location of the measurement, it is a characteristic of local stiffness of the stringbed at the point of measurement. In order to get a well-defined and reproducible across racquets result, manufacturer recommends that measurements are done in the center, which is also the area of lowest stiffness. Deflection when using a fixed force is a different measurement, they are probably somehow related with vibration frequency, but I would be hard pressed to decide which of the two is more relevant to description of how the ball bounces.

====

In my son's project, which I very briefly described in my post from Jan 12, he used several criteria and concluded that three best proportional stringing methods were (in no particular order) Sergetti, Dire Desire, and Proportional to String Length. USRSA and Jet were clearly inferior. Proportional to String Length is what Irvin published, but since I measured lengths of all strings and did a lot of math with these numbers trying to make sense of the Sergetti tension sheet several months before I learned that Irvin posted an Excel sheet with the same calculation, I got used to call it Proportional to String Length.

I strung 4 identical frames with VS Touch + RPM Blast, with these three methods and with reference (standard method). We are going to test them during this coming long weekend and will invite several tennis buddies to collect some statistics on personal impressions - how much difference they see, what they prefer.

Of course, Dire Desire just does not work correctly with poly, their basic assumption that string tension can be reduced to achieve the same string deflection works with soft strings but fails miserably with stiff poly which does not deflect much more with lower tension and which requires, per the formula, negative tension on short strings to achieve the same deflection as the longest strings. I had to replace everything with less than 11 Lbs or negative with 11 Lbs, which is the minimum of my machine. This will probably skew the DireDesire results to some degree. And of course this basically leaves only Sergetti and Proportional to String Length methods as viable options.

If / when we collect a meaningful statistics, I will share it.
 
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tennisbike

Semi-Pro
Off Topic: but proportional related.

Here is one set of Stringmeter data from one string job I did, based on length.

At this point, this 58 SG/48 poly hybrid stringbed feels pretty good. But again my "taste" changes. I enjoyed many soft pocketing stringbeds with low #40 poly or 50lb SG. But then an ancient Pro Kennex 90 sq. in. w/ Ashway Liberty 16 @47/44 lbs felt more firm and I like it. It was also proportional. This one is slightly stiffer than I like but I like the consistency. I think people call this low launch angle. I like a little more pocketing on volley. The SG glide on the poly, though the poly get a little kinked. I think it's fine though, moving cross make notching main string less.
 

AndI

Rookie
First round of testing.

Conditions: four frames Wilson RF 97 Autograph, same strings (Babolat VS Touch 16 (natural gut) on the mains, RPM Blast 17 (poly) on crosses).

Stringing:
1) Reference: same tension on all strings, 56 Lbs mains, 54 Lbs crosses, DT = 39 (per ERT-300).
2) Sergetti: Reference 55 Lbs, DT = 39.
3) Proportional to String Length, tensions calculated based on 56 Lbs main / 54 Lbs crosses, DT = 38
4) Dire Desire, claculated based on 56 Lbs main / 54 Lbs crosses. I used SDST of 0.227 and deflection of 28.5 for gut and SDST of 0.15 and deflection of 26 @55 Lbs for poly, based on data from the string testing article referenced in DireDesire desctiption and Tennis Warehouse string testing data.
Algorithm does not work well for poly and gives negative tension for some strings, all values that were negative or less than 11 replaced with 11 Lbs [the lowest tension on my machine], DT= 36

DT was measured right after stringing with ERT-300 tennis computer. All racquets were strung on Gamma X-ELS.

Testing was done with a ball machine, each participant made several rounds swapping racquets and was hitting for at least half an hour, mostly from the baseline. Participants were asked to not look at the labels and refer to overgrip colors. At the end, they were asked to arrange racquets from the best to the worst.

Known limitation of testing: all three people in the test today have been playing using Sergetti tension pattern since last summer. This fact may have skewed the results somewhat, since there may be a certain expectation how the racquet should feel.

The results were surprisingly similar. Everyone noted right away that racquets feel quite different, but one had to go through several rounds to come to a conclusion what feels better and rank the racquets from best to worst.

A:
1) Sergetti
2) Proportional to String Length
3) Dire Desire
4) Reference
Note: 1 and 2 felt close.

N:
1) Sergetti
2) Dire Desire
3) Proportional to String Length
4) Reference
Note: 2 and 3 felt close

M:
1) Sergetti
2) Dire Desire
3) Proportional to String Length
4) Reference
Note: 1 by far better than 2-4.

It was noted by M. and A. that Reference felt much stiffer, M. also thought it had less power.

The scale of differences, in my opinion, is similar to what one may feel when testing different racquets, or what one may feel when testing different strings. In a way, it is a third level of fine-tuning on top of the the level of racquet and the level of strings. When racquet feels right, and strings feel right, this is the way to make it feel even more tuned to the one's idea of "perfection".

I hope to invite a few more people (this time, not familiar with proportional stringing) over the weekend.

If someone is in Portland, OR, and is interested in participating over this weekend, shoot me a PM - we might work something out, most likely early in the morning when ball machine and scattered balls do not disturb other people on public courts. The more people, the more statistics, the more interesting :)
 
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AndI

Rookie
Talking about what one sees with ERT-300, below is a map of a reference stringing method (from my son's science project). The string was Babolat Addiction, strung at 55 Lbs, mains and crosses.


The color coding has the following meaning:


The existing definitions of "sweet spot" are confusing, in my opinion. What my son was looking for, is the size of the green area in the middle of the racquet where the DT is relatively consistent and ball bounces the same, predictable way.

White area was an interesting find. These were spots where ERT-300 could not measure tension and was giving error messages. We believe this is because amplitude of vibrations in these areas is too low. ERT-300 does a frequency sweep and looks for resonance. If signal is below threshold, it gives an error message. The white area has the shape of an arc, consistent with arc of low or no vibrations from book of Brody, Cross, and Lindsey "The Physics and Technology of Tennis", but in their test it was in upper half of the racquet and here it is in the lower half.
 

AndI

Rookie
ERT-300 Maps of proportionally strung racquets are dramatically different.



Here, Proportional to the Length is on the left and Sergetti is on the right. I would not over-interprete the differences in maps, but would emphasize differences in comparison to the reference stringing.

First, the size of green and yellow areas seems to have gotten a little larger, compared to Reference. It is difficult to quantify, though, because of overlapping white area.

Secondly, the low vibrations area, i.e., the white area, got dramatically larger and overlapped with the green area (which makes it different to accurately determine its size).

Clearly, ERT-300 is not quite up to the task, it would be good to measure both amplitude of vibrations and frequency, but this little gadget is what we have at home and it is great for what it is. White does not mean "no vibrations", it means "vibrations are below the threshold of ERT-300". Green, yellow, and red does not mean "high vibrations", it only means vibrations are above the detection threshold of ERT-300.

DireDesire, Proportional to the String Length, and Sergetti methods had the largest green+yellow areas, or the largest white areas, or the lowest mean tension across the spots which could be measured (which indirectly means that green/yellow areas are relatively larger). This is why one could not determine which of these three methods is better based on these measurements alone. And this is why we are now doing practical testing, to complete this project.

All credits for these graphs and this work go to my 11-year old son. It is not a PhD thesis but a 6-th grade school science project completed using consumer-grade equipment available at hand. He strung all test racquets and completed all measurements. My role was to sponsor him by the way of paying for the strings used in this project (Babolat Addiction, a mid-grade multi-filament string) and by offering opportunities for discussions.

We think, sweet spot is a combination of a large green/yellow area, preferrably combined with reduced vibrations. Definition known from the work of the Australian team, point of zero vibrations, is just too narrow to make sense and too small to be a real sweet spot. But ultimately who cares, what is important, is what feels better.

One can argue what is better and debate if one is rich enough to spend $23 on Sergetti tension sheet or rich enough to get a free spreadsheet for Proportional to String Length method kindly shared by Irvin or tension sheet from DireDesire, but there is no doubt that proportional stringing dramatically changes the way how string bed performs.
 
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Karma Tennis

Hall of Fame
@AndI, what a fantastic couple of posts.

Congratulations to your son and yourself for such a wonderful piece of very interesting work.

While I'm not into the Propotional Stringing gig for a number of reasons, I do find it an interesting discussion.
 

AndI

Rookie
Thank you, Karma Tennis!

Reporting on result of one more test. N. did a very thorough job going through several rounds with each racquet. His preferences were:

1) Reference
2) Sergetti
3) Proportional to String Length
4) Dire Desire

What is interesting to note, is that one probably could expect that he would prefer "Reference" because his racquet is strung with poly. He thought that proportionally strung racquets were a little soft to his taste, and of course larger sweet spot and less vibrations would create a feeling of softness.

This was an interesting observation because, indeed, if you got used to stiff stringbed, any proportional stringing might feel way too soft, for the same reference tension. This goes back to the idea that a perfect racquet should complement player's weaknesses, help him/her to overcome those weaknesses, without taking too much toll in the areas of his/her strengths. From this standpoint, proportional stringing is not a universal, one-good-for-all method, but a way to shift parameters of the racquet in a certain direction which may benefit some but perhaps feel excessive for the others.

With four racquets in test, one has to hit for 30-60 mins and go through multiple rounds to come up to confidently rank the racquets in the order of preference. They all feel different, but it is not a black and white type of difference but rather shades of grey. It is interesting to watch how preferences develop and change during such testing.
 

AndI

Rookie
Thank you, Dags!

For the sake of completeness and fairness, here are the results of another subject who participated in our test, we will shorten his name to "B."

I am very hesitant to even report his preferences for the simple reason that he spent less than 10 minutes hitting with the racquets and went through only one round. He only wanted to play and did not care about the test, despite the fact that the test was the reason why I invited him. I guess, I picked a wrong person to invite. He also seemed to know little about stringing because he texted me a question if we had my own stringing machine and then asked to bring it to the court so that he could see it. I was, like, really?

I think a qualified response requires at least half an hour of hitting shared across the four racquets. It just takes time to adjust to the weight and balance of a racquet which is different from yours and attune yourself to differences; RF 97,as heavy as it is, does not make this task easier. In this sense, "B." did not meet the qualification requirement and his response cannot be considered a statistically meaningful ranking of string beds according to the criteria of this test.

Anyhow, I will report on his rankings as well. His opion was very different from everyone's else:

1) Reference
2) Proportional to the Length
3) Dire Desire
4) Sergetti

Here, clearly, he ranked the stiffest stringbed first and the softest last.

As I think about the last two tests, I might go as far as suggesting that those who have full bed poly strings on their racquets, especially strung at tension in the mid 50s or higher, i.e., those who value stiff string bed, would find proportional stringing too soft and are more likely to dislike it. Those who prefer softer strings or lower string tension have a good chance to find that they love it. And of course for those with elbow pain, a combination of softer strings with proportional stringing could be a gift from Heaven.

I think it is somehow consistent with what other people shared in several threads on proportional stringing in this forum, but now it seems to start falling into a consistent picture. I wonder what other people who tried proportional stringing think after reading this?
 
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Karma Tennis

Hall of Fame
As I think about the last two tests, I might go as far as suggesting that those who have full bed poly strings on their racquets, especially strung at tension in the mid 50s or higher, i.e., those who value stiff string bed, would find proportional stringing too soft and are more likely to dislike it.
The nice thing about high tension full beds of poly string is that players who are used to them can quickly feel when it is time for a fresh restring.

I wonder if the Proportional Stringing methods offer a similar benefit?
 

bluesjumper

New User
Yes, I've found it I double pull to pre-stretch on my lock out machine I get higher final tensions.
I'm curious how much longer it took you to string the racket? I typically don't double pull, and when I wrote Sergetti they said there would be 27 tension changes (for 16x19). And do you have any sense if it's given more life to your strings?> (I typically cut my full poly or poly hybrid after 8-10 hours).
 

Kevo

Legend
I've tried proportional stringing a few times, and I always end up back to the regular old reference tension method. I also use fully poly typically, and I find that the properties of the string seem to matter more to me than the slightly improved feel I might get from proportional stringing. So for me, I'd rather just find a better string and reference tension than spend a lot of time on the proportional stringing. I can see why some people might like it better. It does soften things up a little and might improve the feel a bit as well. It's probably much easier to prefer if you aren't the one having to string the racquet. That alone is probably about 50% of the decision for me.
 

AndI

Rookie
I'm curious how much longer it took you to string the racket? I typically don't double pull, and when I wrote Sergetti they said there would be 27 tension changes (for 16x19).
You need to pay more attention to what you are doing and which string you are on, so proportional stringing requires more metal effort, but typically extra time that is required is about a minute, and certainly not more than two. All it takes to change tension is to press a few buttons. This is quick - unless your machine has a manual tensioner which takes longer to adjust.

An electronic constant pull tensioner which can be calibrated within a wide range of tensions and which is easy to adjust is highly recommended, if not even required, for proportional stringing. Dropweight is also a constant pull system which is very accurate, tension-wise, by design, so in theory it can be used, but adjusting tensions for every string is much more involved. I am not sure if proportional stringing is possible with floating clamps, though.

When considering time to string, one should also consider that proportionally strung racquet holds tension longer and generally requires less frequent restringing. I found the claim of longer useful life (slower decrease of tension) on the Sergetti web site and did a little research of my own, by measuring two racquets, strung with and without Sergetti pattern, with the same starting DT, over the period of several weeks. My observations confirmed that Sergetti racquet loses tension slower. I am hesitant to provide a number as it was about a year ago and my recollections may not be accurate, but I think tension decay time on Sergetti strung racquet, in that case, was either 50% or 80% slower, judged by the slope of linear fit to the graph of DT versus log of time since restringing. Which means, you may save more time through restringing less frequently than you lose by adjusting tensions - and recoup the cost of tension sheet very quickly through reduced frequency of restringing.

I can give a "Fresh" example: for the test described several posts above, two identical racquets were strung with the same tension, one with Sergetti, the other one "traditional", natural gut on the mains, RPM blast on crosses. Both showed DT=39 after stringing. Both were played with quite a bit (for testing with the ball machine and for regular play), I estimate 5-8 hours in total within 7 days, with each racquet. A week after stringing, "regularly" strung racquet shows DT = 36 (drop 7.6%), Sergetti shows DT = 38 (drop 2.5%). This is a significant difference. It is recommended by ERT-300 manual that one restrings after 10% to 20% drop in DT.

I did not do the same measurements on racquets strung with other proportional methods, but I suspect they would show a similar longevity.

UPDATE JUNE 1. Now it has been 8 days since restringing. I measured all 4 racquets used in test.

Sergetti: drop from DT=39 to DT=37, 5%.
Proportional to Length: drop from DT=38 to DT=35, 7.8%
DireDesire (modified due to negative calculated tensions with poly) drop from DT=36 to DT=33 (8.3%).
"Regular": drop from DT=39 to DT=35 (10%).

I am just sharing our measurement data... Perhaps my son will look into it as his next year's science project? One has to do systematic measurements over a long time with least squares fit to the data to get statistically meaningful results, and this is a lot of work. But there appears to be a trend.. It looks like regularly strung racquet may require restringing quite a bit sooner than proportionally strung racquets.

By the way, according to all literature data, tension decay is linear with respect to LOG of time. 5% drop after the first week does not imply that the next 5% drop will be in the next week, it may take quite a bit longer.
 
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AndI

Rookie
I've tried proportional stringing a few times, and I always end up back to the regular old reference tension method. I also use fully poly typically, and I find that the properties of the string seem to matter more to me than the slightly improved feel I might get from proportional stringing. So for me, I'd rather just find a better string and reference tension than spend a lot of time on the proportional stringing. I can see why some people might like it better. It does soften things up a little and might improve the feel a bit as well. It's probably much easier to prefer if you aren't the one having to string the racquet. That alone is probably about 50% of the decision for me.
Thank you for your great feedback! This is what I suspected, and you confirmed it so nicely. Larger sweet spot means less vibrations, and this is perceived as "softer"; larger area of similar values of DT around the center also means that the racquet should feel softer if the ball hits it off center. Poly is a stiff string and those who use it got used to its stiffness and stiff feel, so it makes so much sense that proportional stringing may feel like a change in a less desired direction - unless one has developed a tennis elbow and wants to get more arm-friendly feel without going away from poly, or likes poly in general but not its relative stiffness. I am curious, though, if proportional stringing would increase the "useful lifetime" of poly strings.

In contrast, with natural gut extra reduction in vibrations and increase in sweet spot size feels like step in the right direction - at least for me. Probably the same applies to many multifilament strings.
 
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Irvin

Talk Tennis Guru
You need to pay more attention to what you are doing and which string you are on
A tip that works for me is I never get more than 1 ahead when stringing the mains. When both clamps come together at the throat or head I change tension. For crosses all odd strings pull in one direction and even in the other direction. I place a small clip on the 5th cross and can easily tell what cross I'm on. Then I move the clip from the 5th to 10th to 15th.
 

AndI

Rookie
Irvin, thanks, the idea with the clip is absolutely great, thank you for sharing! This is so simple and yet so helpful!
 

Irvin

Talk Tennis Guru
@andl Walmart has some 1” colored clothes pins in the hobby section that work good.
 

Subaruvich

Semi-Pro
I measured dynamic tension with ERT-300 of each cell of my matched Vantage racquets one strung with Sergetti method other with regular method. Not the best photoshop work, but here are the results:
https://we.tl/s-9CsTNWOFng
Started from center and moved away until I got error notification. Tension reference for both racquets was 22/21kg. The sergetti one was freshly strung. The regular one had couple of hours of playtime when I did the measurements, so there was some tension drop.
Can we say the sweespot with sergetti is much higher up in the hoop?


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AndI

Rookie
I measured dynamic tension with ERT-300 of each cell of my matched Vantage racquets one strung with Sergetti method other with regular method. Not the best photoshop work, but here are the results:
https://we.tl/s-9CsTNWOFng
Started from center and moved away until I got error notification. Tension reference for both racquets was 22/21kg. The sergetti one was freshly strung. The regular one had couple of hours of playtime when I did the measurements, so there was some tension drop.
Can we say the sweespot with sergetti is much higher up in the hoop?
Very interesting! The key question is: WHAT IS THE SWEET SPOT? The first attempts to define it were made by R.Cross and coworkers. They actually defined several types of sweet spot, one can refer to their publications and books for more information, but the bottom line is that those definitions do not make much sense to me. For one, their "sweet spot" is either a physical spot, not an area, or, in the best case, an arc. And yet there are so many discussions of larger or smaller sweet spot, depending on racquet and strings. This does not fit into the model of an isolated spot. Then, how likely it is that you would hit ball with a specific, very localized spot on the racquet? Those spots are valid physical "properties" of the racquet, but they do not seem to make much sense as definitions of the sweet spot.

In my opinion, a more practical definition is the area of the racquet in which strings deflect to a similar amount when a ball hits them, so that the ball bounces back in a very similar manner anywhere in this area. If you hold a racquet horizontally and let a ball drop from a short distance, it will bounce much higher from the center than from areas close to the frame. We want ball bounce to be very predictable, repeatable, reproducible, and as independent from point of impact on the string bed as possible - otherwise its trajectory would strongly depend on which spot on the stringbed the ball hits. If we hit a ball and sometimes it goes too far or sometimes into the net, we want this be caused only by our technicque and not by the small differences in contact point on the racquet face.

Since the ultimate goal is to hit the ball around the middle of the racquet, we want the area of similar strings deflection be centered around the middle of the racquet and be as large as possible. By the way, the string bed deflection test - distance to which string bed deflects under a defined load - was the method used for validation of the claim that Sergetti method increases the sweet spot. It makes sense to me because larger sweet spot defined like this means more consistent and reproducible ball trajectory after it is hit with the racquet. Dynamic tension is somehow related to string bed deflection under defined force, as DT correlates with string bed stiffness. So, returning back to ERT-300 maps, we want to have as large green area in the maps above as possible.

In addition, we would like to see the string bed vibrate after impact as little as possible, which means, (a) not to have a well defined resonance frequency, so that amplitude of vibrations is small, and (b) decay quickly. This has two benefits - less vibrations transferred to the arm, and string tension lasts longer as vibrations are small shortenings and extensions of the strings repeated dozens or hundreds of times after the ball hits. Each wave of vibrations contributes to string extension and ultimately to a tension drop and loss of elasticity. I guess, if each string has its own tension, it will detune their oscillations quite a bit more than in a regularly strung racquet and would reduce the likelihood of resonance of the string bed?

Large sweetspot with less vibrations unavoidably feels like a softer racquet. This is to be expected.

So, we want to have a large green area in DT maps, and also a large white area. Unfortunately, white masks out green, so ERT-300 maps can be hard to interpret - you always see the white but not always see the whole green area as part of it may be not measurable because ERT-300 cannot detect and measure the resonance frequency.

I think these Vantage racquets or strings installed on them have remarkably good ability to dampen string bed vibrations. There is a lot of white even in a racquet strung with standard method. Also, it seems that the green area may have expanded in Sergetti, but with different tensions, the maps are a little hard to compare.

I wonder, what kind of strings did you use?
 
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Subaruvich

Semi-Pro
I wonder, what kind of strings did you use?
It was Silverstring/Rslyon hybrid.
I am doing the same experiment today with two matched Angell V3 TC95 racquets with gut/poly hybrid at 26/25kg tension reference.
Regarding Vantage, I can say that the one with Sergetti method has less power and more consistent stringbed response, which makes sense.


Sent from my iPhone using Tapatalk
 

2ndServe

Hall of Fame
is the fundamental point thaat the longer strings should have a higher tension and the shorter ones be looser?

If I string my long mains at 58 lbs as I got towards the edges I should reduce tension by say 10% each string.

And the crosses should be even a lower tension as they are shorter strings.
 

Imago

Hall of Fame
is the fundamental point thaat the longer strings should have a higher tension and the shorter ones be looser?

If I string my long mains at 58 lbs as I got towards the edges I should reduce tension by say 10% each string.

And the crosses should be even a lower tension as they are shorter strings.
Not that simple. Have you taken into account the phase of Mercury?
 

AndI

Rookie
I would not jump to this conclusion. It is more complex than that. They use a different measurement method for stringbed stiffness, i.e., how much the stringbed moves (deflects) under a static load, or what load is needed to achieve a fixed deflection. It is similar to what Stringway Stringlab 2 measures. It is somehow related to DT measured with RacquetTune or ERT-300 (a metric based on resonance frequency of the string bed without deflecting it), but it is not necessarily the same thing. They are even called differently, Dynamic Tension vs String Bed Stiffness. I think it is safe to say that maps of DT and SBS show similar features and change in the same direction as string tensions change, but they are not identical. One needs a different equipment, not readily available to tennis enthusiasts, to measure what they measure. Stringlab 2 is the closest, but in its factory design, it only can measure in the center of a racquet.

They used a specialized analytical lab with proper equipment for their measurements.

When their patent is approved and published, we might learn more about the assumptions and goals. For now, it is pending in UK.
 

Rabbit

G.O.A.T.
They used a specialized analytical lab with proper equipment for their measurements.

You sure they don't just use a spreadsheet with percentages plugged in for string length? If they used "specialized analytical lab with proper equipment" wouldn't they need to account for each racket individually to ensure they adjusted for stiffness, weight, layup, etc?
 

AndI

Rookie
The patent is for mathematical algorithm. They have information on the web site what parameters are taken into account. Strings, tensions, and racquet are the parameters which you pick from the menu when you place an order. Testing equipment was used as proof of "mission accomplished", validation of the result, not as a development tool.

I would recommend reading the basic information provided on their web site. This answers many questions.

Moreover, I can tell you from my experience, if you buy two tension sheets for the same racquet and strings, e.g., for 52 Lbs and 55 Lbs, tensions in one sheet will not be proportional to tensions in the other. In other words, you cannot get a 52 Lbs sheet from 55 Lbs sheet by multiplying all numbers in it by 52/55. Not just the tensions, but the shapes of the distributions along mains and crosses are also somewhat different. Additionally, tensions are not proportional to string length. Sometimes shorter strings have higher tension than the longest ones. Although all proportional stringing methods have generally a bell-like shape, sometimes with some oscillations, the Sergetti profiles are the most weird from them all.

Method where tension of each string is strictly proportional to the length of the string is one of the known methods, and the most logical one, pretty much implied by the name "proportional stringing". Irvin created a spreadsheet to calculate tensions for this method and made it available in one of the parallel threads. It actually works quite well, better than some other proportional methods, and it is free. Another free method is DireDesire, but one has to keep in mind that it does not work with poly or poly based hybrids as calculation oftentimes results in negative tensions. One can find DireDesire sheet on this forum as well.

I had an opportunity to test all known proportional stringing methods (and I wrote about it elsewhere on this forum). I personally prefer and use Sergetti, and so is my son and friends, but it is a personal preferences matter. Proportional to string length method, as well as DireDesire, both feel quite a bit better than non-proportional stringing and trail closely behind Sergetti, in my opinion. Sergetti method takes into account strings and racquet, so difference between Sergetti and other methods may vary depending on strings and racquet. This is the reason why your findings may be different from mine, and of course it is quite subjective.
 
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gazz1

Semi-Pro
I have also purchased several sheets and agree with Andl's observations.

My main observation, common on all of my sheets, is that the cross strings around #5 are proportionally higher than say #14 (5 is 5th from the start and 14 is 5th from the end for 19 crosses).

So for arguments sake, if a racket with 19 crosses had string #5 and string #14 of equal lengths, then string #5 would be strung at a significantly higher tension.

This makes a lot of sense because the racket frame has distorted (widened) after stringing the mains. Extra tension has to be applied to the earlier crosses because once the mid and late crosses are strung, they will make the frame narrower again therefore reducing the original tension on the earlier crosses.

The proportions of tensions by string also vary for different string combinations even if selecting the same tension and the same racket.

There's definitely a lot more going on than just the adjusting tension relative to the length of the string.
 

Imago

Hall of Fame
My main observation, common on all of my sheets, is that the cross strings around #5 are proportionally higher than say #14 (5 is 5th from the start and 14 is 5th from the end for 19 crosses).
One should not be a proportional racket scientist to draw this conclusion. :)
 
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