Cutting Down Racket Length

 

With Covid-19 still raging, especially the Delta variant, many are staying home voluntarily despite full vaccinations. 

Work-from-home remains the default in Singapore. 

Probably because of this, a lot of my old friends picked up tennis. A former colleague, now in his 70s and retired, pursued tennis rigorously. Taking lessons twice a week and playing another two more days with his wife. 

We caught up and played. He used an oversized head-heavy racket recommended by his coach. 

And I noticed the strain on his face as he struggled with his timing on every forehand shot. He thought that was normal and how tennis ought to be played. His coach commended his strokes. 

When I took his racket back for measurements and restring, I was shocked! 

His second hand racket had been modified previously. At 28 inches long, it weighed 297 grams with a balance of 36.5cm and a swingweight of 381 kg/cm2! 

Despite removing all the lead tape I could find, it remained too head-heavy. I suggested to cut down by half-inch for a start and he agreed. 

Some weight was added in the handle end to rebalance. The old kevlar/synthetic gut was cut and restrung with full poly at about 40 lbs using proportional stringing. 

He loved it from the first hit! 

"So easy!" he exclaimed! 

Longer is not always better. The specs has to be within his strength ability. He immediately sent in his wife's racket to be re-worked too. 

 

 

 

"Breaking Into" Rackets

Some months back, a junior competitive player asked for advice on how to continue playing with an arm injury.

Then, he was using a Babolat strung very tightly with full poly. Switching to a hybrid or even full multi did not help.

I felt a more flexy racket was necessary. After testing different sticks, he made his choice and stuck with the new racket since. According to published specs, the RA was around the low-60s.

During a recent restring, he started lamenting how the accuracy was still poor compared to his previous stiff Babolat.

I was perplexed.

He has been happily using the four new stick for about four months. Even managed to beat some team-mates he regularly lost to. Why the sudden nostalgia about his old Babolats?

He rang up his coach, passed me the phone and we spoke.

Top on my mind was whether he was "arming or swinging" (link) the new stick. This technique has huge implications on accuracy, especially when one is switching from a stiff flex to something softer. I also asked about his timing.

All seemed well. 

To ascertain, I even dropped in on one of his training sessions to see for myself how he was hitting. And there he was, leaking some forehand shots just a tad right. First serve consistency was not as good as what I recalled.

I borrowed and played a tie-break each with all four of his sticks. Then realised that the flex has changed! The rackets has all broken-in and the graphite has softened!

The pieces started falling into place. Like when he mentioned that he felt he was not able to "load" the strings and "pocket" the ball as much as before. And the reduced spin. And the "not enough time" to shape the ball.

It was finally confirmed after we put the rackets into a Babolat RDC machine. The RA stiffness for all four of them now measured 59, 60, 60 and 61 compared to 63, 64, 63, 65 when new.

To address this, I proposed to:
(1) add some lead tape to increase mass, which would "stiffen" the dynamic flex, &/or
(2) lower the tension of his existing strings, &/or
(3) change to a thinner gauge or softer string.

As it was near an important competition, he selected option (2). It was a quick-fix that addressed most of his problems. His accuracy returned while the arm pain stayed away.

Perfect!




     

Optimal Tensioning?

After a friendly game, a teenager was asking how to fine-tune his string tension after deciding his preferred strings.

He was aware of the adage "String loose for power and tight for control", but did not know how to make adjustments.

My answer was simple:

Generally, the tennis game can be grouped under four categories:
(1) serve,
(2) return of serve,
(3) groundstrokes, and
(4) net play.

The real challenge was that, regardless of string type, each of those categories performed best at slightly different tensions. 

So it's more of WHICH aspect of his game he needed help with. Or, was a particular style of play from any opponent giving him troubles.

Stringing very tight would help with his first serve's accuracy and return of serves for both first and second serves. But he might lose some spin for second serves and groundstrokes. So some angles and placements would be cut off. Touch shots would be challenging, or could even feel dead.

If his strategy was on using heavy spin on both serves for an opponent that he knew could not handle spin, then low tension could do wonders! Even better, if he charge forward after his spin serves to volley and finish the point early. That would avoid any potential high rebound or loss of control issues with his groundstrokes from the baseline. Best used for opponents who struggle returning spinny shots and have a tendency for weak/short returns.

Since he has multiple similar rackets, was not a string breaker, and could well afford to test strings, I even recommended different setups for different sticks! That would cover a wider spectrum of different opponents he may not have played with.

Yes, there would be adjustment issues when changing rackets. But so far, I observed that all who tried my unconventional setups, took mere minutes to acclimatize.

For an average Joe, say ntrp 3.5, that would probably cost him about 1 to 1½ games at most. Never the entire set, unless he was already struggling against a much stronger player.

Plus, the abrupt change ALWAYS seemed to rile up the opponent more! After reading, analysing and understanding your pace, spin, movement, placement, etc, you messed up the variables again!

Just take note this is no replacement for hard work and training. Only an enhancement. An unorthodox one.

ProKennex Black Ace Micro with Fishing Line

Every now and then, I receive requests to help repair, restore or restring some vintage frames. 

Occasionally, some wanted to test exotic string setups in their rackets.

The most typical remained - vintage frame with damaged/extinct grommets carrying a strong sentimental value.

But strangely, whenever I mentioned the costs needed to get those frames back into playing condition, all of their "sentimental values" dissipated instantly! Poof!

The owner of the Black Ace Micro could not find anyone willing to restring his 22x30 racket. Neither was he willing to learn how to do it himself. He KNEW it was not a simple job!

Knowing my fondness for such rare collectibles, he offered to swap with something of approximate value. Rackets, stringjobs, or other peripherals.

A deal was made and it became my new toy.

From online searches, specs for the Black Ace Micro are:
Tension: 28-42 lbs (string crosses 2 lbs tighter than mains)
String Pattern: 22mains x 30crosses
Start mains at throat, skip 10Bottom & 12Bottom
Start crosses at 10Top
Shared holes: 13T & 13B
Note: Start crosses on side A of grommet strip
Source: USRSA Stringer's Digest

Playtest:
- This was strung at 35 lbs, right at the middle of the recommended tension range.
- Control was impressive. There was a very nice pocketing that rebounded very quickly, like natural gut. It could be due to the extra number of strings in direct contact with the ball.
- Impact was very soft but the strings felt tight and firm.
- There was absolutely nothing to suggest this was pulled at only 35lbs. Tranlated, the tightness would probably play close to about high 40s lbs in my 16x18 ProStaff Classic 6.1.
- I had expected spin to be poor with such a dense pattern. But I was very wrong. Ball bite was very good and spin was very controllable. 
- The variance in spin between deliberate high spin and flat shots were greater than with normal 16x19 open patterns.
- Even flat shots were easy to aim and re-direct.
- The flex seemed very low and I could feel the throat bending during impact as it absorbed the power. Not as whippy as a woody, but close. Probably RA 40s?
- Serves were a little challenging. Too much power and the frame would flex, affecting accuracy. So I used a spin serve throughout the game I played.
- Even after about an hour of play, there was zero notching on the fishing line.

"Pulling" a Prank!

Just before April Fool's day, a friend was dropping off two rackets to be restrung when I asked if he would like to test some new stringing idea I had. 

We have done this many times, so he readily agreed, not even asking what was to be done.

This friend held a firm belief, that in order to play his very best, the strings must be freshly strung and pulled tight. He uses multi/syn gut hybrid at 67/65 lbs and restrings after every 8-10 hours of play.

For the pair of matched sticks, I strung one normally, and "experimented" with the other.

Of the total 35 (16+19) mains and crosses, I hand-pulled 20% of them, which is a total 7 strings!

Specifically, all four outer mains and crosses, plus the left mains #3, #4 and right mains #5 were tensioned by hand, aided by a starting clamp while mounted on the stringing machine!

All I intended, was to prank him and get him to loose some control. Then restring that for him at my expense. Instead, this threw up a new discovery!

From the first few hits, he noticed one racket was strung looser. "Not very much looser", he said, but "distinguishable". I was surprised he found it playable and asked him to tell me more, not revealing the secret to him yet.

Thinking it was some exotic setup, he adjusted his strokes and tried to identify areas where this setup could play well. Although looser strung, it was completely different from how his usual setup played after it had lost tension. 

This was livelier and controllable! Totally unlike the loss of control and unpredictable rebound of worn strings that had lost tension! 

Then I dropped the bomb...

Suffice it to say, he is now happily experimenting with slightly lower tensions and beginning to enjoy them.

More Power More Spin!

While I took a two decades break away from tennis, many of my old buddies did not.

I tracked down another old mate recently, hoping to catch up on some tennis. Unfortunately, it's his turn away from tennis now. Not a voluntary decision though. 

He developed severe tennis elbow and wrist pain around the ulnar area (link). Most days, he cannot even use his master hand to drink his morning coffee. It is disheartening to see him look seemingly healthy but suffering from such pains.

He shared how his quest for "more power more spin" drove him to stiffer and stiffer frames strung tightly with full poly. But he forgot he was aging!

Just a few years ago, he was the typical profile of many tennis players today who:
- wants more spin,
- wants more power,
- uses light & very stiff frames,
- strings too tight (above 50s) with full poly, and
- restrings his rackets only every few months.

But synthetic gut can generate heaps of spin too! And add plenty of comfort along the way!

To test that, I invited a few current tennis buddies, who are heavy spinners to try syn gut. Sadly, most declined, claiming syn gut is so very passe...

C and PK were two who matched the typical profile and accepted the blind test. (PK admitted that the last he used syn gut was a few years ago.) 

All they know, were their rackets were strung with syn gut. Nothing else was communicated.

Both were asked to track amounts of spin, comfort, control, power & durability compared to their usual full poly strings.

Here's one stiff frame I restrung with full syn gut...

When I cut the poly, there was minimal snap. The string stayed close together with only a tiny gap. To me, that was an indication either the poly was strung too tight or the string was dead from use.

Another clear sign was the very severe notching on the mains. To have continued playing with this was akin to committing arm suicide.

A modified proportional stringing method was used to better distribute the string tension around the stringbed. That helps to add ball cushioning and spin.

Playtest:
- Over the March 29-30 weekend, both C and PK clocked 4 and 5 hours of play respectively with the fullbed syn gut.
- While their ages may be apart by about a decade, their feedbacks were generally similar.
- Note that I did not watch nor play with either of them.
- I grouped their findings for ease of reading below...

Initial impressions
- Both thought the all black syn gut looked like full poly.
- C was completely blown away by how comfortable the syn gut played. 
- Barely 15 minutes into his rally with his usual buddies, C could no longer contain himself and let the cat out of the bag. His partners then took turns trying his racket and declared it "unusually advantageous".

Comfort
- Unanimously very good.

Spin
- C does not normally hit with heavy topspin as he felt it was an inefficient stroke and took away too much of his power. However, this setup provided very easy access to the spin he had wanted. He pulled off a lot of slice winners and "quite a few heavy topspin shots easily".
- I found PK's feedback on spin a little contradictory, so I thought I'll just quote what he wrote:

"Spin was normal but I find that I needed less power to generate the spin. I used new US open balls (US version). The whole racket was filled with fur."

"I felt my slices was awesome today as most of it went in with a lot of spin."

"This is the first time I have seen ball fur on the strings. Never on any polys I used even with hexagon shape strings."

"Tried to use 100% full swing. I noticed that if I hit prematurely, the ball files out. Spin was good only when the contact of the ball was during the brushing motion. If I can get my timing correct, my shots will be really deadly."

I play lousy tennis compared to C and PK, but from PK's words above, it seemed like there was indeed access to a lot of spin. However, some stroke or timing adjustments may be needed compared to their regular full poly setup. Or, was PK too excited to whip the ball that he was hitting early?

Control
- C did not notice any drop in control and accuracy. 
- However, C felt that the comfort of the syn gut stringbed gave him a lot more confidence to execute difficult shots without the fear of "stinging pain" on off-centred ball contacts. If this was taken into consideration, he felt control improved.
- Another observation by C was a huge increase in the sweetspot size. He felt he miss-hit less balls with this setup.
- PK commented:

"Control was a little off today maybe because I was not used to the strings. I could not hit hard with this setup as I could feel the trampoline effect."

"I felt control was a little off after 3rd hr of playing."

Power 
- From what I heard and read, there was an abundance of power experienced by both. Only PK used the word "trampoline" once. (Note: PK is in his mid-30s, about 1.8m tall, fit, muscular and very athletic)

Durability
- There was no string breakages, no mention of string movement or notching. So I deduced it either did not happen or it was so minimal it did not bother them.
- Since I did not get to meet them, I could not measure the frequency drop after play as well.


After their feedback, I expressed thanks to both for their willingness to risk messing up their strokes to try this setup. My only objective was to prove that syn gut CAN offer heavy spin with comfort. From what I have read, I am satisfied.

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.

Wilson Pro Staff 95s with Syn Gut + Spin Challenge

Online forums reported on how quickly strings break in the PS95s. While the very open 16x15 stringing pattern is excellent for spin, it is terrible for string durability.

As a result, everyone strings with either full poly, kevlar or 15g syn gut. Even then, most enjoyed only a few hours of play before it snapped.

After trying Z's PS95s (link), I was exceedingly curious: 
(1) how long would 17g syn gut last in that racket, and
(2) between racket, type of strings and stringing method, which factor would influence the amount of spin more?

Since Z also felt that his PS95s was due for a restring, he gave me a free hand on how it was to be done. 

I chose full syn gut modified proportional stringing with base tension of 50lbs. A lot of the strings would end much MUCH LOWER than the recommended range of 54-64 lbs!

Then we took it out for a playtest cum spin challenge with some of my previously strung spin setups.

Rackets in above pic, from top to bottom:
Wilson Hammer 5.8 + syn gut varied tension (link)
Wilson ProStaff 95s + syn gut proportional stringing
Head Prestige Mid + full poly
Dunlop AG200 + fullbed fishing line (0.9mm mains)(link)
Yamaha EOS + 17g syn gut (link)

Our ranking was unanimous. From best spin to worst, it was:

1. Dunlop AG200

2. Yamaha EOS

3. Wilson PS95s

4. Wilson Hammer 5.8

5. Head Prestige Mid

What we gathered there was:

Stringing Pattern

Even dense string patterns (18x20) can generate heaps of spin. Although the Dunlop was strung as 16x19, the gaps between the strings remain small and tight. The fishing line bites extremely well compared to the full poly in the Head Prestige, which ranked last.

String Wear

The Yamaha ranked 2nd while Hammer was 4th. Reason being different hours of use - Yamaha had about 6 hours versus 10 hours (or more) for the Hammer.

Stringing Method & Swingweight

The Yamaha, PS95s & Hammer were all strung with a modified form of proportional stringing that varies tension among the strings. The same 17g syn gut was used for all. 

Despite that, spin in the Yamaha trumps PS95s. Why?

I believe it's the low total and low swingweight of the PS95s. Both the Yamaha and Hammer have modified swingweights of about 330-340 kg/cm² whereas the PS95s was only about 300 kg/cm². That is a huge difference!

String Type and Tension
It is indisputable that poly is excellent for spin. But with so many different types of polys & co-polys, many stringers get confused about what tension to use. 

All polys have a very narrow useful plastic range before it fails. Once exceeded, poly plays totally dead (link). The 18x20 Head Prestige was strung at 60lbs.

Here's some pics of the stringbed after play... look at the amount of ball fur...

So what next?

I believe there is a lot of modification potential in the PS95s. Forums are rife with comments to add weight under the buttcap. That's one avenue to explore.

Another would be to add swingweight. (link) I cannot help but wonder, did the PS95s designers intentionally kept swingweight low to prevent the strings from snapping too fast, like in the Steam 99s? 

According to their spec sheets, both PS95s and 99s have 16x15 string patterns. Other specs like total weight and flex are very close. However, swingweight differs by 28 kg/cm².

It is Z's racket after all, he'll call the shots how he wants it to be done after this syn gut wears or snaps. Or maybe, he'll just stick with the 18x20...

An Experiment on Tension vs Power and Control

Whenever I recommend someone to drop their string tension, they would all unanimously comment on how uncontrollable the stringbed would "trampoline" and all control would be lost.

I asked a doubles group if they would be interested to conduct this tension test and they agreed immediately. One offered three of his similarly matched rackets for this experiment. Cost of strings were shared.

Only tension differed, and ranged from 20lbs to 80lbs.

The methodology was kept simple:
1. Rackets
Out of a total of 7 rackets, three different models of rackets were used. All had 16x19 stringbeds, RA stiffness ratings in the 60s, total weight between 328-344g. Balance between 31.9-32.5cm.

2. Strings
The same synthetic gut was used and strung using the same one-piece pattern on the same machine.

3. Power
Since we do not have sophisticated radars, we measured it subjectively. While two were playing singles, the other two non-playing would observe their serves and groundstrokes from the net and at both baselines behind the players. All four would record their observations, with 1 as lowest and 10 highest. Differences in depth of shots were very apparent. Players were rotated to allow everyone to test.

4. Control
Different serve placements were attempted for flats and spin. Groundstrokes were targeted at corners using both flat and topspin shots for both wings. Both players and observers would rate the stringbed control independently.

The chart below summarises our group findings.

*The three matched rackets were strung at 30, 50 and 70lbs.

At 20lbs:
Hitting deep groundstrokes was almost impossible. All had to raise the net clearance to above 6ft to clear the service line. Topspin shots curled down too much and we had to flatten our shots to hit deep. Pocketing was so deep the rebound was delayed.

At 30lbs:
The stringbed felt so much tighter than 20lbs. The delayed rebound was gone and the stringbed became much more predictable. Power was still low but the less pocketing from 20lbs gave us a better transfer of energy to the ball. Still had to flatten our strokes to hit deep. 

At 40lbs:
Coming from 30lbs, all noticed a huge sharp increase in power. If there was any trampoline, this was it! Too much power and too little control. We recorded the most number of double faults and out balls at this tension.

At 50lbs:
The trampoline from 40lbs seems to be reined in. Control stepped up significantly. However, we were split. Two felt it was playable but could not swing freely and confidently. Two felt it was neither here nor there and actually preferred the 30lbs!

At 60lbs:
It felt dead! It could be the brand of syn gut we were using or that we started off from 20lbs. There was a huge shock with every ball impact. It felt familiar. Probably something we felt all the time hitting with our regular sticks and tension but had become numb to it. Among all the tensions, the vibrations appeared highest at 60lbs.

At 70lbs & 80lbs:
There was very little ball feel left. Almost no pocketing. The stringbed felt "slippery" whenever we tried to spin the ball. Could be because of the low pocketing and almost zero sliding of the strings. Because of the lack of "bite" and power, we resorted to hitting the ball flat and it played quite well that way. Except for the high unforced errors due to too low net clearance. We hit the tape too much.


Note:
This "test" was done some months back. We had scribbled the observations on a few sheets of paper which we lost. A clown just found it in his messy car boot!!!

ProKennex Black Ace 98 + Syn Gut @ 28 lbs

After some calculations, I decided to restring this racket at 28 lbs. From the last few sessions, pocketing was missing and I wanted more (link).

While cutting out the strings, I noticed the frame moved a lot. There was plenty of "crackling" sounds. 

When the mains were cut, the racket "popped" and lengthened, pulling the cut mains string wide apart.

The same "pop" was experienced when I snipped the crosses. 

Immediately, I understood what was that "missing element" I was searching for in my last post! The hoop of this frame is extremely flexible!

So soft, that the hoop flexes not only during ball contact, but even during stringing! And that's where all the cushioning and dampening came from!

I have never used a racket with such a soft hoop. Not even some of the old woodies I had, nor the RA54 Yonex RD-7. That's why I could not understand this stick.

The downside is, with so much flex in the hoop, the cushioning absorbs a lot of feel and power as well. Upon contact with the ball, the racket bends backwards much more than stiff frames. 

All the pieces are coming together. Now I understand why I always miss the line to the right whenever I try to aim down the line. It's because the racket flexed more than what I am used to!

To "counter" this flex, I want a softer stringbed. Think about it, if the stringbed deflects more upon ball contact, then the frame would bend less.

I am not "boxing" the stringbed this round. Since the hoop is so soft, I will keep it simple to avoid any possible distortions.

Width before and after stringing is 26.4cm and 26.1cm respectively. Hoop narrowed by 3mm.

Length of hoop remained constant at 34.7cm.

Playtest:
- After a little play, I adjusted the swingweight down to about 340 from 345. Since the sweetspot is just a tad above the middle, I wanted the lead tape lower to be aligned with the sweetspot to add more mass there. That would "stiffen" up the hoop slightly through added stability.
- At 28lbs, the racket plays better than the previous 35lbs. Control and spin are still there.
- There is absolutely no trace of trampoline at all. Just a little bit more pocketing than at 35lbs.
- The 18x20 configuration is amazingly stable even at such low tensions.
- Needless to say, comfort and dampening reigns supreme in this racket.
- Since this is only the first session after re-stringing, I will post a more detailed review after the second or third use with this stick. Let the strings break-in first.
- If you cannot imagine a soft hoop/frame flexing during ball impact, take a look at the video below of Federer's forehand shot at 1:16.

06Jul2013 update:

- Used the BA98 for some drills and rally today.

- The previous "wobbly" frame feeling has gone. With the added lead tapes, I cannot feel anymore of that weird impact I felt previously.

- Overall, I added about 15 SW points, bringing the racket's swingweight to 346. Now, ball impacts are stable and I can feel the racket "going through" the ball instead of the ball pushing the racket off-balance.

- With the added "punch", ball impacts sounds much nicer too. It is now a "pop" instead of a "thud". Another confirmation that plowthrough has improved.

- From the previous string wear pictures, I know I am hitting the sweetspot consistently enough so it cannot be due to off-centre hits that cause the unstable feeling at almost every shot last time.

- Spin is good despite the 18x20 pattern as the gaps are quite big.

- Comfort is very good. Nothing to worry about even for injury prone wrists or elbows at all.

- If I want to continue fine-tuning this frame, the next challenge would be control. Not that it is bad now, but I want a greater degree of confidence when aiming for corners or down the lines. With this, my success rate is probably 6/10 whereas my stiff PSC6.1 can easily score 8/10.