Racquet tuning

fpsanti

Rookie
I have two racquets Yonex Vcore 98 tuned by a professional ATP stringer
Their specs are now identical:
<1g mass difference
<0.1 cm balance difference

I noticed that when I play with racquet #2 I do not play so well and I feel it's a tad less manouvreable.
I could not believe that I am able to tell the difference of the two sticks with almost identical specs.
So I asked a friend to shuffle the racquets and give them to me. I was able to tell which one is #1 and #2 with 100% accuracy.

How would you explain this?
What could be causing the difference of the two racquets and how can I solve this?
 

tim-ay

Legend
I have two racquets Yonex Vcore 98 tuned by a professional ATP stringer
Their specs are now identical:
<1g mass difference
<0.1 cm balance difference

I noticed that when I play with racquet #2 I do not play so well and I feel it's a tad less manouvreable.
I could not believe that I am able to tell the difference of the two sticks with almost identical specs.
So I asked a friend to shuffle the racquets and give them to me. I was able to tell which one is #1 and #2 with 100% accuracy.

How would you explain this?
What could be causing the difference of the two racquets and how can I solve this?

Yeah, one of them could be more polarized, probably the one you like more. Sometimes in the fight to get balance and SW the same, along with static, you can end up with weight in different places on the frame. I’d rather be off 3 or 4 grams static and have SW and balance the same, polarizing the frame a bit more for the one you find less maneuverable. But that’s me…
 
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fpsanti

Rookie
Yeah, one of them could be more polarized, probably the one you like more. Sometimes in the fight to get balance and SW the same, along with static, you can end up with weight in different places on the frame. I’d rather be off 3 or 4 grams static and have SW and balance the same, polarizing the frame a bit more for the one you find less maneuverable. But that’s me…
I also prefer a more polarized racquet.
Is there a machine which could measure TW?
I could bring it to another shop and have it measured there
 

tim-ay

Legend
I also prefer a more polarized racquet.
Is there a machine which could measure TW?
I could bring it to another shop and have it measured there
You can measure TW on a SW machine. The problem is that any small error makes it very very difficult to get accurate numbers. TW is just in the teens vs. SW in the hundreds, so measurement error kills you. If someone has a calibrated SW machine, you can at least try it. Just measure the racket on edge and flat, the difference is twist weight.
 

bfroxen

Rookie
If the mass, balance, and SW are matched, the racquets are equally "polarized". You could be feeling stiffness variation or twistweight (TW) differences.

You can get an idea of stiffness with a Babolat RDC or by measuring the resonant frequency of the frame with a phone app (any tuner app that will give you the dominant frequency from a sound).

As @tim-ay mentioned, measurement error makes TW measurement difficult. Most SW machines don't have the precision required for useful TW measurements. The one I developed is precise enough, but it's still not easy. I've found that often, the butt cap is not completely square, and the resulting position differences of just tenths of a millimeter will wreck the twistweight result. Averaging measurements in the opposite orientations can help a bit.
 
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