StringSavers with Used/Worn Poly Works!!!

A playing partner, CK, lamented on how fast his poly setup "dies". 

My understanding of poly death could be attributed to two areas - tension loss and no more snapback.

Since both issues were previously addressed satisfactorily (link), I whipped out the "String Glide" and inserted sixteen pieces.

Compared to before the string savers, CK felt the stringbed firmed up. He also heard the strings sliding and snapping back much better.

I hit a few shots with his racket as well. Even with more than 10 hours of play on that set of 1.10mm poly strings, I felt the stringbed tightness was restored good enough for me. I could trust the strings for directional control and swung freely. Spin was very good too. Much better than the 4-hours-old poly stringjob I was using in my racket that session.

In another session, I planted sixteen pieces into another playing partner, M's stringbed.

M was initially skeptical but allowed me to proceed anyway.

After some hits, and swapping back and forth with his other matched racket with exact strings setup, M commented:
- the stringbed felt a little more dampened with less vibrations which he enjoyed, and
- pocketing was deeper and it felt the ball stayed longer on the strings which gave him more time to shape or re-direct the ball at the last minute.

From my side, the result was very clear. M's shot dispersion and control was unmistakable between his three rackets. I could tell immediately when he picked up the one with stringsavers.

After the initial impressions, both CK and M popped the same question: 

"Where did you buy the stringsavers?"

The verdict is clear.

Since string savers are so much cheaper than a stringjob, I believe this could be a viable method to extend the playing life of the poly strings. 

As always, if you choose to do so, pay extra attention to how your wrist, arm, elbow and shoulder feels. Live to play another day!


18Dec2014 update:
After hearing positive feedback from CK and M, DL adopted the use of stringsavers in his open strings racket (link) as well.

After insertion, DL commented:
- the slight dampening reduced some stringbed vibrations without the need of a dampener,
- it played more comfortable with better pocketing, and
- added more spin and control.


Coincidentally, these stringsavers have all been tested with positive results in full poly (CK), poly/syn gut (M) and full syn gut (DL).

Budget Strings?

The lure of fresh strings is difficult to resist. If not for its price, everyone would follow the restringing patterns of their favourite players on tour.

When sufficient unfulfilled needs arise, a business opportunity comes by. So budget strings popped up, some at merely ¼ or less the price of original brand names they claim to replicate.

Since I have yet to figure out how to grow money on trees, I jumped on the bandwagon too. Then got off. And on. And off. Multiple times. (No brands nor models will be mentioned here)

There are multitudes who "swear by" the quality of these strings. And probably an equal number who threw out unused reels.

So far, I have succumbed to cheap natural guts, syn guts, polys and kevlar. Out of about nine different strings I tried (many multiple times), I thought a few polys were not bad, playing almost 70-80% similar to the real deal. 

Usually, two similar sticks were strung, one with original strings, one dud. They were rotated during play every fifteen minutes. A single new can of balls was used.

At 15 minutes, both were almost indistinguishable. At 30 minutes, significant tension loss started creeping in. At 45 minutes, control and spin departed to string heaven. Budget price for budget durability too?

The kevlar did not feel like kevlar to me. More like garden wire. (link) The syn gut was completely devoid of any feel or feedback. It gave me the impression it was strung with coaxial cable.

Buying and stringing the budget natural gut was like playing russian roulette. One batch was kinked with white fold-lines straight out the package. Could have been the shipping, so after some negotiation, I settled on 50% price for a replacement and some freebies.

Nevertheless, I strung it up at 52 lbs. And it snapped in the bag overnight, right at the kinked spot. The replacement arrived in better shape. However, my gripe was the huge variability in gauge from start to end. I think it ranged between a 15g to 17g. And it was uncoated.

As it is, my tennis game is pathetic enough. Add to that my Mr Bean styled footwork is enough to make anyone collapse in laughter. Unless I'm bent on working towards ntrp 0.0, I would be giving all these budget strings a miss.

Or I could save them for competitors who beat the crap out of me everytime...

Difficulties of Hybriding Strings

Many asked for recommendations how to hybrid and pair strings. 

Most commonly:
- What tensions for mains and crosses? Any differentials?
- Which string for mains? 
- Which for crosses? 
- What gauge?
- Prestretch?

Personally, I do not enjoy hybrids. (I have even tried tri-brids and quad-brids!) No matter what I pair together - kevlar, syn gut, multifilament, natural gut, soft poly, stiff poly, fishing line, steel wire or grass trimmer line, it was extremely difficult to balance them well.

Inevitably, one string would dominate over the other. Usually, the feel and playing characteristics of the mains prevail. Once in a while, the crosses. 

I am far from solving this puzzle, but I believe it has something to do with how the strings behave at different tensions.

When pulled to 55 lbs, the amount of total stretch observed in the following strings were:
- natural gut 6~7%
- synthetic gut 9~10%
- multifilament 10~12%
- poly 3~4%
- kevlar 1~2% 

The numbers were in a range due to different batches and brands. 

These same strings, when pulled an extra 10 lbs, bringing them to 65 lbs, yielded an incremental stretch of:
- natural gut 0.4~0.7%
- synthetic gut 0.8~1.1%
- multifilament 0.5~1.2%
- poly 0.1~0.3%
- kevlar 0% 

The conventional wisdom is to string the softer string a couple pounds tighter. Using poly/syn gut at 53/55 lbs for example, would see them stretch about 3.5% and 9.5% respectively when strung.

However, during ball impact, the amount of additional poly stretch available is less than half that of the syn gut. Even though the strings are inter-weaved together, hard impacts bring the poly into deformation territories. 

In other words, poly gets stretched beyond its elastic range and loses tension. Over time, the feel of the syn gut increases. (see "Impact Loss" in table below)

And that's only assuming one plays with the racket immediately off the stringing machine. 

(from Tennis Warehouse University String Performance Database link)

When allowed to rest from being strung at 51 lbs each, the "Actual Pre-Impact Tension" has already dropped to 30/39 lbs! This differential would only get wider with every ball hit.

Having established this, then how about we string poly higher instead? Would that help to compensate for its larger pre-impact tension loss compared to syn gut?

Probably yes. But only for a while before impact tension loss brings down the tension again. How fast this happens depends on how tightly strung it initially was and how hard one hits the ball.

Another often overlooked factor is string gauge while pairing. Many choose the same gauge for hybrids, typically 17g or about 1.25mm.

Using the same example of poly/syn gut earlier, from my own measurements, the 1.25/1.25 mm combination would thin out to about 1.20/1.13 mm. 

Below pic shows a 1.40mm syn gut became 1.25mm strung.

Below shows a 1.25mm syn gut thin to 1.10mm strung.

An easy way to calculate this diameter change would be to use the percentage stretch as a proxy. A 1.25mm string with 10% stretch, usually becomes 1.13mm (0.90 x 1.25) strung.

Simple engineering dictates, the thicker the material, the stronger the support. This could be another factor why the poly mains dominate when paired with syn gut in the same gauge. Well, but many people like it, so it's their choice.

Perhaps after reading this, one could start deducing why Federer is touted to be using 1.30mm gut mains and 1.25mm poly crosses:
0.93 x 1.30 = 1.209 mm
0.96 x 1.25 = 1.200 mm

The same gauge combination of 16G gut and 16L poly for Serena Williams as well? (link) And Sharapova? (link) And Nishikori? (link)

That said, my personal preference is still a full bed of the same string. Primarily for its ease of adjustment and consistency after play. If I were to cut strings out after every hour of play, then it might change.

After all, according to the Luxilon String Analysis at the 2013 US Open (link, refer pg 6-10), more than 70% of the competitors used the SAME STRING in both mains and crosses. 

Special thanks to Irvin for highlighting that report. (link)

Different Generations of Poly Strings

Despite having been around for about three decades now, many still seem to have misconceptions about poly strings. 

From its infant days, poly has come a very long way. Broadly speaking, we are now in the fourth generation of poly strings.

Without referring to specific brands or models, the first generation poly string was simply slick, stiff and dead. Nothing else.

Elasticity was so low that every ball impact took some tension off through string deformation. String life was so pathetic that it was probably better monitored by the number of shots one hit, rather than by time used.

While the spin was hugely rewarding, the stiffness must have affected quite a few players. As a result, a second generation of poly was born.

Additives were added to soften the string and the term co-poly surfaced. When strung within a specific tension range, from about the mid-40s to low-50s lbs, a higher level of comfort was achieved through greater elasticity. 

Within this range, tension holding also improved. However, when strung below or above, it still played as boardy and stiff as the first generation.

I believe it was from this generation of poly that caused many misconceptions about poly's useful tension range, up till today.

The third generation poly was heavily marketed with more "bite". That was when shaped co-polys came aboard. Five-sided pentagonals, hexagonals, spirals, twisted and fused, and many with rough edges became wildly popular. Comfort improved further.

The most popular fourth generation poly string now is Luxilon 4G. Aptly named, as "4G" simply refers to fourth generation. Tension holding and comfort were touted to be "uncommon for a poly".

Somewhere around the third or fourth iteration, the useful tension range widened tremendously. Many reported great results from as low as 20+ lbs (link), to as high as 90 lbs! Yes, with full poly!

Personally, I have tested quite a few between 30 to 70 lbs. Surprisingly, at either 30, or 70 lbs in the same racket, it played almost equally boardy! But the one with lower tension loosened up much more rapidly, whereas the tighter strung took about an hour to "break-in" before playing well. 

I could not find much difference in the amount of spin between the four generations. Variances were only on comfort and tension holding.

Whichever generation of poly it is, keep in mind it was introduced solely to generate tons of spin. To achieve that, it has to be made very slick and very stiff to snap back effectively. Slick and soft would not work as well for spin.

As a result, poly demands a strong loading to play well. And that could mean very long loopy full swings, or rackets with high swingweights and open string patterns. 

Tennis balls that are a little heavier, have high bounce and are "hard like rocks" for natural gut or synthetic gut could also possibly help with the string loading required. Just be wary of your own shoulder, elbow, arm or wrist tolerances.

Soft Shaped-Poly Hybrid Test in MFil300

Quite a few of my playing partners use this string and shared good reviews. When I tried their rackets, I was pleasantly surprised at how soft, yet firm this poly played.

A friend whom I string for asked if anything could be done to add a little more "finesse" and pocketing for touch shots like volleys or mid-court put aways. A little more power would be nice too.

From his reel, he cut out about 24 metres and asked me to "play around" with them, then share my findings. To prevent bianess, brand was withheld.

Some simple string test results I did revealed interesting differences from earlier poly strings. 

This third/fourth generation poly string:
- has a much softer material composition that could be dented with my fingernails with some effort,
- appears to have a stiff inner core,
- has an inelastic elongation component only about half of some of my second generation poly strings,
- has its overall elasticity reduced slightly as well.

Since he wanted more pocketing and touch, the best way was to hybrid with a softer string. In this case, a syn gut in the crosses.

With its soft outer layer (not a coating), the poly was easy to string compared with traditional polys. Touch wise, it reminded me a little of pvc coated garden wire.

Playtest:
- Even though we played about 48 hours after stringing, the first few shots felt a little uncomfortable. A muted kind.
- It was not harsh. There was definitely some "cushioning" in the stringbed but insufficient. Somewhat like jogging on a concrete path with a very old pair of running shoes?
- Since I was not a poly lover, I handed it over to another partner to do the breaking-in, and to let me know his opinion only after the entire session.
- After about an hour, I resumed testing.
- The "harshness" was almost completely gone. It started to feel more like a fullbed of stiff and crisp syn gut.
- The "loading" of this hybrid was interesting. The stringbed felt tight for both low and high powered shots. 
- Taps and blocks sometimes felt like it was not enough to load the string. That was fair. Yet, full swings conveyed a "not enough pocketing" kind of feedback sometimes.
- Middle of the range shots produced the best results. Those 60-70% smooth swings elicited soft, controlled feedback with spinny balls. It was very enjoyable and made me want to just rally that way forever.
- Low powered shots were slightly lower powered than other polys. All-out swings were also lower powered than other polys. Smooth swings yielded the closest to "normal" kind of power compared to other strings.
- This advantage was, power control could be delegated to the stringbed with less variation in our swings. We could swing away more freely.
- It also made me think, could this be the string company's attempt to market poly to "softer hitters"?

DIY Textured Strings?

Many of the newer polys are shaped or textured, claiming it would increase bite and spin.

Despite many polys I've tested, "The One" remains elusive. But the idea of a rough texture increasing spin through higher friction appeals to me. (link)

Since I no longer break strings like I used to, I cut them out after about 8-10 hours, or when they've lost their mojo.

Instead of cutting out one that's due, I thought I'll rough it up as an experiment.

Even with a 60 grit, sandpaper was too smooth. I wanted it REALLY rough! So the bastard file was deployed.

It was so rough it was impossible to draw the stringbed against the back of my hand. Perhaps a really sadistic person could do that, but I couldn't. Neither my partner.

How rough? Just think of a grating tool...

To preserve some durability, only one side of the stringbed was filed. The other was left untouched as a comparison.


Playtest:
- Before and after roughing the strings, I measured the stringbed frequency. It was the same. So tension was a non-factor, even after play.
- Within the first few hits, it was obvious that ball feel was A LOT better on the rough side. The difference was something like hitting with a 18g string versus a 16g.
- Another surprising find was an improvement in directional control.
- Even when hitting totally flat, it felt so much easier to aim and direct the ball. 
- Comparing both sides, the smooth side felt slippery and that the ball was skidding a little across the strings during impact! Without a high speed camera, there was no way for me to verify that, it just felt that way to me.
- To ensure the greater accuracy was not mere psychology, I got my partner to feed me balls while I aimed at targets I usually found challenging. Five shots each were attempted with each side of the stringbed, alternating at every shot. The result was telling!
- I got my partner to try while I fed him easy balls, and he shared exactly the same sentiments.
- With the extra ball-to-string friction, all kinds of spin improved across all strokes, including serves.
- This extra bite on the ball was easily seen after less than ten strokes! The tennis ball fluffed up like a pom pom ball!
- The stringbed pic is below.

- Keep in mind, this stringbed was already used for about 9 hours before this. It was dead enough for me to want to cut it out.
- If you wish to test it, go easy on the roughing process. I snapped the earlier two attempts, this was the third.
- Even this snapped overnight after about an hour of play.

Wilson Blade 93 (18x20)

After being convinced that strings can make a huge difference to how the racket plays (link), Z started having second thoughts about selling all his 18x20 sticks and converting to open patterns.

Unfortunately, the fishing line I used in the Dunlop (link) was not readily available. So he asked for recommendations. And I suggested a shaped poly with syn gut hybrid.

Z had already restrung the Blade 93 thrice with different setups, none to his liking. This was the last chance for the 18x20. He had two Blade 93 and has already sold one.

I wanted to get it right for him. The added advantage was, I have played with Z, so I understand his hitting style, strength, spin preference and racket prep. 

Despite the decent swingweight (333 kg/cm²) of this racket (link), string tension would be kept low due to the dense 18x20 string pattern. The base tension would be 45 lbs for mains and 43 lbs for crosses, with some variations at different strings.

Z was so excited that he picked up the racket for play right after I finished stringing it. He arranged for another hitting partner and agreed to update me via sms.

After just an hour of playtest, a flurry of messages was exchanged between Z and me. I extracted a few below...

-------------------------------------------------------------------------------
Z: The blade bites like hell!!!! My topspins were heavier and deeper. U revived my blackie!!!!!!! Omg this is much better than the 95s!!! U hv to try it. I can feel the cutting and the biting!!! And though tension was low. Its well controlled and just nice. Deeep enough but doesnt fly the balls! U are genius

Z: Did u remove some weight from the racquet! The power is there even though i felt like i was late for the ball

me: Thanks! Glad u like it. It's a proven setup... done it many times...

me: Yes, prob dropped a few grams cos syn gut lighter than poly. Your hands r very sensitive.

Z: U hv to try the blade and blog it...i swear it could b one of ur finest work
-------------------------------------------------------------------------------

Do not be afraid of using low tensions in poly/syn gut hybrids. Polys are designed with that in mind in the first place. Worst case scenario, is to send a few tennis balls into orbit in space. Then, just cut the strings out and add a few pounds of tension in the next re-string.

Here's a pic after about 10 hours of use... and it's still going strong and playing extremely well!

Unknown Poly String Test

After reading "String Death & A Little History on Poly Strings..." (link), an acquaintance, CK, asked if I could help him test a poly string. 

He bought a reel of that poly based on good reviews but has never liked it. On the contrary, his experience was very different from what he read. 

CK was worried if international shipping could have damaged the string through heat, humidity or other stresses. I assured him not. And poly probably has a long enough shelf life (unstrung) to remain playable even for his great great great grandchildren!

Primarily, CK wanted to know: 
(1) what is the "useful tension range" of the poly, and 
(2) what are my experiences after using it.

He handed me two coils of about 12 metres each in an unmarked envelope. I have asked not to be told what brand or gauge to remain unbiased.

According to his peers, CK is about a ntrp 4.0 all courter. He uses a 100 sq inch racket with 16x19 string pattern. The closest similar configuration I have is my Wilson Hammer 5.8. As mine was just restrung, CK agreed to wait until my strings are worn before I test his strings.

Physical attributes:
- It is a black coloured poly.
- Looks hexagonally shaped.

- When I tried bending and twisting a short end of the string, it felt very firm and stiff. To me, that was the first hint it could be a stiff poly.
- The string measured very close to 1.15mm on my gauge. It was consistent at ten random spots throughout the entire coil. I'm amazed as there are not many polys this thin.

I chose a poly/syn gut hybrid first, to test how it would perform in just the mains. Also, I like to start from extreme ends then work back towards the mean. So tension would be 55/53 lbs.

While stringing, I weaved a few crosses with the same piece of poly to get a feel of how stiff it was, and also to understand how easy it was to notch. The mains sliding action while playing is a common cause of notching and breakage. This poly is easily notched.

On its own, it can be difficult to assess how much spin it has. So, I always bring a familiar racket and strings setup as a benchmark. It's the Yamaha again.

Playtest observations:
- This is a stiff and low-powered poly. It played so much boardier than almost every stiff poly I've tried.
- The string did not yield much. Surprisingly, it felt very similar to dead poly - flat and lifeless. 
- I thought it could be still "too fresh" from stringing, so I hit some hard and flat rally shots with us standing about 2 metres behind the baseline to try to "break-in" the strings. Still no change.
- Spin was pathetic. A poor performance considering it is hex-shaped. Even when I got my partner to feed me easy balls, I could not get my topspin to kick. Many flew out. I am beginning to understand CK's disappointment with this premium string.
- I moved my dampener to 12 o'clock. That added about 10 swingweight points to my plowthrough. Still dead.
- After an hour of hits, it still felt boardy. Any attempts to serve with heavy spin were futile. There wasn't much string movement nor ball fur stuck on the strings either.

- Compare that with the ball fur on the Yamaha with very well worn full bed syn gut below.

- Incidentally, I took a very close look at the Yamaha's syn gut and realised that the main strings' sliding action has "abraded" the cross strings and made them flat instead of round! What do you think that'll do for spin? Easier to slide?

- I'll give this poly some time to settle-in before thinking of my next course of action.

Note:
I will eventually know what brand this string is, but I will not be posting any details about the strings here.

19Mar2014 update:
- I think my strokes are too weak to soften the stringbed, so I got a big hitting poly-loving friend to play with this racket for an hour. Strangely, he loved it.
- I tracked the stringbed frequency. A day after stringing, it dropped about 18Hz. After an hour of play, dropped 13Hz. After my friend hit for an hour, dropped 7Hz. Total drop is only 38Hz so far, and at a declining rate of loss!
- This poly has very impressive tension holding and stability! 55 lbs was definitely way too high!



26Mar2014 update:
- While I enjoy string testing and exploring fanciful string patterns, my old body cannot withstand the rigours of daily tennis anymore. So I delegated this poly test to another poly loving partner of mine. I will still hit with it but only for a short while, and intermittently.
- I cut out the previous setup and restrung at 45/43 lbs. Ten pounds is a significant drop, I think.
- Through googling, I realised that there are actually factory pre-stretched poly strings for sale. To me, this defies logic. There is so little elasticity in poly, and most are already over-tensioning poly. And now factory pre-stretched? I suspect this mystery string could be one.
- Not surprisingly, after about 90 minutes of play, this friend remarked that the string played almost similar to the previous setup at 55/53 lbs! Huh? Could be a first clue this string was pre-stretched.
- As usual, I'll let the stringbed settle and try it out myself.


28Mar14 update:
- I played an hour with this setup. Perhaps my friend has already broken-in the string for me, but it felt so much softer and responsive today compared to previously.
- Spin was more than at 55 lbs but it did not wow me nor my partner. 
- Comfort improved a lot. Power was still low.
- After a total of about 3 hours of hits, tension loss was a measly 28Hz, or about 2.8 lbs.
- Pretty sure this is the pre-stretched stuff now.
- Will advise CK to string this poly really low. 40 lbs could be a good start for a hybrid and high 30s for a fullbed. Reason being it was pre-stretched, and also to allow some ball pocketing, without which there would not be heavy spin.

Yonex Super RD Tour 95 + Full Poly @ 38/36 lbs

Having tried Kevlar mains with poly crosses earlier (link), I thought I should give full poly a chance too. So I decided to hybrid Black Fusion mains with Super Nova cross @ 38/36 lbs.

I know this sounds silly, but the whole reason this setup was chosen was because my friend simply preferred ALL black strings! What a clown!

Playtest:
- very very soft feel, slightly mushy after a few hits
- have a strange buzzing feel and sound from strings (I think the strings are too loose...)
- does not have the typical tight feeling of a stiff string
- control and spin is average
- very good pocketing
- very high-powered, so much that a lot of shots are long
- while playing, I get the feeling that poly at these tensions are not displaying their full potential yet

Yonex RD7 + Poly/Syn Gut @ 45/50 lbs

Black Fusion is a star-shaped co-polyester strings that is designed to have more bite on the ball. The objective is more spin. 

It is so stiff and sharp that just from pulling the softer synthetic gut cross strings during installation, the synthetic gut already started fraying!!! The Synthetic Gut Titan is really a very soft and comfortable string!

After 2 hours of playing:
- very slight tension drop
- the poly strings really 'bites' the ball for really insane spin
- ball contact is very nice and soft and comfortable

After 4 hours:
- cannot feel any further tension loss
- the sharp edges of the poly string has worn off
- surprisingly, the synthetic gut did not fray much


After 6 hours:
- still no further tension loss
- spin is similar to unshaped poly main strings
- synthetic gut still holding up well
- this is definitely a setup I'll use again, maybe with a small tweak of tension

Racket Specs:

Yonex RD7

27"

95 sq inch

340g strung

Stiffness 54

Stringing Pattern 16 x 19

Strings:

Pro Supex Black Fusion 18g 1.19mm mains @ 45lbs

Pro Supex Synthetic Gut Titan 16g 1.25mm cross @ 50lbs

Here's what happened to the tennis ball after about 2 hours with Black Fusion