Experiment: Poly/ZX hybrid - 90 lb mains, 40 lb crosses.

#1
Frame: Shortened (26.7") Leaded-up (362 SW, 13.54", 13.43 oz.) BLX Blade 98.

Mains: 1.23mm SPPP
Crosses: Monogut ZX Pro Black

Prestretch of Poly: Using my pulsed body-weight lean method, I got about 7" extra permanent length in the 20-ft segment of SPPP.

Stringing mains: With each 90-lb pull on the drop-weight, I needed to wait about 30 seconds for the string to stretch before the lever stopped dropping - I estimate I got an additional 3" total additional prestretch on the string during stringing. I omitted the outer 2 mains (since I prefer the Blade without the outer mains - the frame is really a 16x20 with extra holes drilled near the edge).

Prestretch of ZX: I reused the set of crosses that had been in the racquet for more than 100h of playing time (until the 16g kevlar broke). It's safe to say these were thoroughy prestretched.

Stringing of crosses: The reused ZX allowed me to do the first 17 crosses. I used a 3-ft scrap of previously prestretched ZX Pro Black to finish the bottom 3 crosses.

Initial Comments:

The racquet shortened by approx 5mm upon removal from the stringer (so now 26.5" post-stringing) - this is about an extra mm of shortening compared to my usual 90/40 kev/ZX formula.

Feel when bouncing ball on strings in living room: Feels crisp (short dwell time), but very springy at the same time. I'd say it feels a bit tighter than kev/ZX at 90/40, which is to be expected based:

If tension loss is neglected, in theory, a poly/ZX 90/40 hybrid should have much greater preserved tension differential than a kevlar/ZX 90/40 hybrid, because the tension in much stiffer kevlar mains drops a lot more per mm of frame shortening compared to poly. This means that, at least initially, the poly/ZX 90/40 hybrid may have even greater spin potential than kev/ZX.

I look forward to testing this out on court.
 
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ricardo

Hall of Fame
#3
The racquet shortened by approx 5mm upon removal from the stringer (so now 26.5" post-stringing) - this is about an extra mm of shortening compared to my usual 90/40 kev/ZX formula.

If tension loss is neglected, in theory, a poly/ZX 90/40 hybrid should have much greater preserved tension differential than a kevlar/ZX 90/40 hybrid, because the tension in much stiffer kevlar mains drops a lot more per mm of frame shortening compared to poly. This means that, at least initially, the poly/ZX 90/40 hybrid may have even greater spin potential than kev/ZX.
Interesting experiment.

I am just curious.

If the racquet shortened, a significant tension loss occured, specifically on the mains.
I would estimate that at least 30lbs was loss in the mains as soon as you un-mounted the racquet.
The crosses may have gained about 5lbs due to the sides widening (3/9).
So after unmounting, you now have a 60/45lbs.

I know you are aware of this tension loss/gain.
But I sense that this is your intent.
You want to squash the head, thinking that you can store the extra tension for future use.
You believe that the racquet frame is elastic: it will return to its original lenght, form, shape.
In short, you believe that you cannot deform a racquet frame permanently.

So over time, as the string stretches some more, the squashed head will slowly return to its original form,
releasing the stored tension and helping preserve string's tension maintenance.

It is a very good concept.

If I were you, I will carry it further by taking actual measurements.

Thank you for taking the time to do this experiment.
 
#4
Interesting experiment.

I am just curious.

If the racquet shortened, a significant tension loss occured, specifically on the mains.
I would estimate that at least 30lbs was loss in the mains as soon as you un-mounted the racquet.
The crosses may have gained about 5lbs due to the sides widening (3/9).
So after unmounting, you now have a 60/45lbs.

I know you are aware of this tension loss/gain.
But I sense that this is your intent.
You want to squash the head, thinking that you can store the extra tension for future use.
You believe that the racquet frame is elastic: it will return to its original lenght, form, shape.
In short, you believe that you cannot deform a racquet frame permanently.

So over time, as the string stretches some more, the squashed head will slowly return to its original form,
releasing the stored tension and helping preserve string's tension maintenance.

It is a very good concept.

If I were you, I will carry it further by taking actual measurements.

Thank you for taking the time to do this experiment.
Yes - that's exactly the idea. A side benefit is that by stringing mains at reference tension ~30 lbs above the 'dismounted' tension, it's possible to get a very thorough prestretch of the mains (the mains continue to be prestretched at nearly 90 lbs while I string the crosses), which is critical for preserving the differential over time.
 
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#5
Ok - I had a chance to use my 90/40 poly/ZX Blade today for 20 minutes of baseline points.

Basically, the stringbed was pretty freakin' awesome. It played exactly as I hoped. That is, the 'ESP' effect was every bit as noticeable as with kev/ZX, perhaps even enhanced a bit.

For those unfamiliar, the 'ESP' effect is when the stringbed allows you to strike the ball with excellent spin as well as with a full range of attack angles without having to make much adjustment to the racquetface angle. This greatly enhances control, because you can take big topspin cuts or slam hard flat shots without having to make adjustments in face angle like you ordinarily would. It also means that you don't need to make adjustments in face angle to account for variations in spin or heaviness of the incoming ball.

In short, ESP effect combines the best features of a tight/dense stringbed with the high spin-potential of a loose stringbed with good snapback.

Control was excellent. The stringbed really bites the ball on spin shots - I could really make the ball bend sideways midair with sideswipe cuts. And directional accuracy was terrific whether pounding it, ripping heavy topspin, or slicing to a small target.

It played very similar to kevlar/ZX strung at the same tension. Power level was similar. The crisp feel was similar, but maybe with the more "plasticky" bounce of poly rather than the "carpety" feel of kevlar.

When I returned home, I measured the length of the frame. It was still exactly 26.5" (it had not lengthed due to the the hitting session), so that's a good sign that the poly is holding it's tension better than expected.

At least initially, I like it every bit as well as my gold standard (kevlar/ZX at 90/40), if not better. The next test will be to see how the performance and durability holds up over time. I'm a little skeptical that the poly will be able to match the kevlar for durability, and one of the things I like about kev/ZX is that I can "string and forget about" since it lasts 100+ hours with excellent performance.
 
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#6
Have actually previously tried this. Black 5 Edge poly 90lbs mains, Zylex 45lbs cross, in Graph Speed MP 16-19.

Spin effect was their, but grab on the ball was not as much as with Kevlar. Useable yes but Kevlar in mains are a little better.
Main problem with poly in mains at such a differential is they get sawed through very quickly. 30minutes of heavy hitting machine balls and the poly had significant notching.

So Effect is similar to Kevlar mains but short string life I estimate would negate using poly. As the one of the main benefits of the ESP kev/zylex is long term consistent playability. Because at the end of the day a full bed of poly at 55lb plays better for the 1st hour than any any other set up for me, but I can get close with the Kev/zx esp which lasts for weeks and stay the same.
 
#7
Have actually previously tried this. Black 5 Edge poly 90lbs mains, Zylex 45lbs cross, in Graph Speed MP 16-19.

Spin effect was their, but grab on the ball was not as much as with Kevlar. Useable yes but Kevlar in mains are a little better.
Main problem with poly in mains at such a differential is they get sawed through very quickly. 30minutes of heavy hitting machine balls and the poly had significant notching.

So Effect is similar to Kevlar mains but short string life I estimate would negate using poly. As the one of the main benefits of the ESP kev/zylex is long term consistent playability. Because at the end of the day a full bed of poly at 55lb plays better for the 1st hour than any any other set up for me, but I can get close with the Kev/zx esp which lasts for weeks and stay the same.
Thanks. Yes. After 1h of hitting, the stringbed is still playing great, but the poly mains are indeed starting to notch. I think you're right that the poly will break soon.
 
#10
Yes, a week with a full poly job killed my arm. The poly/ZX stringbed seems to have softened up a bit because the poly is notching, so it's less precise than it was initially.
Kevlar/ZX (at 90/40 lbs) is still my number one string setup for overall combination of control, precision, spin, and long-term string-and-forget playability.
 
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