Calibrating and adjusting for reference / dynamic tension

[Dillon4787]

Hi everyone,

So I string for clients, as well as for myself. Something to keep in mind.

For some time, I was using RacquetTune to check in on dynamic tension -- I've used my own readings and the database's string factors. I also know there are several threads on this, but none of them have been totally helpful to this point.

While I was only using RacquetTune as a reference and to track tension loss, I did notice that I was consistently getting readings about 5 lbs. higher than the reference tension I was setting. I chalked it up to the fact that RacquetTune is simply a tool best used to track loss and that was that. That said, I've also noticed my rackets seem to feel a bit tighter than the tension I have been stringing at when I play. Finally, I had a client who uses a stringmeter and allowed to be borrow it and likewise -- about 5-7 (or more) lbs. higher than the reference tension.

I use a Gamma X-ST and a Wise 2086. I recently had the Wise calibrated, but went through the trouble to calibrate it yet again today. I own the Wise 2090 calibrator, which is made for the Wise 2086. Here's how the calibration went.

Prior to calibration:

• Pulled at 45 lbs -- calibrator showed the pull to be about 45.6 lbs
• Pulled at 50 lbs -- calibrator showed the pull to be about 50.8 lbs
• Pulled at 55 lbs -- calibrator showed the pull to be about 55.7 lbs

So on average, just a bit higher than the reference tension. Here's where it gets a bit strange.... it is suggested to calibrate at around 70 lbs. So I set my Wise to 70 lbs and the calibrator read at about 78. Of course, I then adjusted the tension down to match the calibrator and locked that it. Afterwards, I pulled at 45, 50 and 55 again.

• Pulled at 45 lbs -- calibrator showed the pull to be about 44.9 lbs
• Pulled at 50 lbs -- calibrator showed the pull to be about 50 lbs
• Pulled at 55 lbs -- calibrator showed the pull to be about 54.8 lbs

I was happy with those results, so I strung up a racket at 52 lbs reference tension. I pull it off the stringer and RacquetTune is reading about 59 lbs. The stringmeter is reading even higher and it feels to me as if the feel is closer to 59 than 52...

Because I am stringing for clients, I can't necessarily just chalk it up to "go by what feels good" because I can't hit with every client's racket or have any do-overs. I clamp pretty consistently close to the frame and I use the turntable lock when pulling any string that would be obstructed by a mounting arm, but it's also worth noting that I do not use the Wise adapter to bring the height of the wise up -- this is to maintain 360 degree maneuverability with the turntable. The decline from the grommet to the Diablo does not seem significant.

In a word; help?

 

[esgee48]

I do not use the string factors in RT's database. Most are unstretched and that is not usable from a tension perspective. I only use a few strings and I find that I have to pull the tension, ping the string, and enter the other data like length, etc and have RT tell me what is the string factor for the tension. I then save that string factor in a notebook/worksheet. The mass/meter string factor is still a good way to do it, but you need to pull at least a meter of string at ref tension for at least 10-15 seconds to make sure the string stretches if any, then weigh it.

It sounds like you have calibrated the WISE and you are still getting RT readings that says the tension is too high. Try lowering your 'string factors' by 2-3% and see what happens to the readings. See what factor is needed to get a 52# reading. My suspicion is you are pulling your 52# ref tension, but it does not feel like 52# to you. That means you were not hitting with 52# of ref tension historically, but something a few # lower.

 

[Dillon4787]

I do not use the string factors in RT's database. Most are unstretched and that is not usable from a tension perspective. I only use a few strings and I find that I have to pull the tension, ping the string, and enter the other data like length, etc and have RT tell me what is the string factor for the tension. I then save that string factor in a notebook/worksheet. The mass/meter string factor is still a good way to do it, but you need to pull at least a meter of string at ref tension for at least 10-15 seconds to make sure the string stretches if any, then weigh it.

It sounds like you have calibrated the WISE and you are still getting RT readings that says the tension is too high. Try lowering your 'string factors' by 2-3% and see what happens to the readings. See what factor is needed to get a 52# reading. My suspicion is you are pulling your 52# ref tension, but it does not feel like 52# to you. That means you were not hitting with 52# of ref tension historically, but something a few # lower.

So it’s worth noting, I have taken my own string factors before with the method you described and had similar readings. Not with every string, but I’ve definitely done that with a few. I’ll still give the string factor deduction thing a shot, but I’m still concerned how a stringmeter is corroborating this higher tension, as is the feel.

EDIT: Had to take the most recent string factor down by about 9% to get the proper reading to match the reference tension. Gosen OG Sheep Micro 16G was in the database at 1.55 -- didn't get a 52 reading until I took the string factor down to 1.41

 

[esgee48]

If you are confident about the calibration, there is no way for a WISE to pull 59# or whatever if it is set to pull 52#. And you did calibrate and rechecked what it was pulling. Ergo, the issue is RT or the Stringmeter. So, you basically need to find another lower ref tension that sounds and feels right. Maybe use 46-47# ref tension. FWIW, is the original 52# based on when you were using just the ST without the WISE?

 

[Dillon4787]

I\FWIW, is the original 52# based on when you were using just the ST without the WISE?

What do you mean by ST?

 

[esgee48]

just saw your edit. Now you understand what I am saying about most of the DB string factors are not usable.

ST = X-ST. If you based your 52# on your old LO ref tension from the X-ST, you had to assume that the LO pulled a lot of the strings elasticity out before locking. This is a bad hypothesis. I have seen ref tension adjustments of -3# to -7# in order for the string bed to play similarly. Most of the posters in the Stringing Forum talk about 2-4# adjustment down when moving from LO to eCP.

 

[Dillon4787]

just saw your edit. Now you understand what I am saying about most of the DB string factors are not usable.

ST = X-ST. If you based your 52# on your old LO ref tension from the X-ST, you had to assume that the LO pulled a lot of the strings elasticity out before locking. This is a bad hypothesis. I have seen ref tension adjustments of -3# to -7# in order for the string bed to play similarly. Most of the posters in the Stringing Forum talk about 2-4# adjustment down when moving from LO to eCP.

For what it’s worth, I never strung a racket with the original LO. Put a wise on it the day I got it, so that’s not a factor. As for the string factor, I haven’t gotten a reading myself for the Gosen, just telling you what I had to manually change the string factor to to get a 52# reading on RT with that setup. I’m also trying not to get too bogged down with the RaquetTune stuff since two other methods seem too point to a stiffer-than-hoped stringbed as well.

 

[esgee48]

OK. All I can say at this point is you should decrease your ref tension to something you feel is comfortable. Try 46# and see if the feel or DT is in your wheelhouse. If it is, then that is your new ref tension.

 

[fritzhimself]

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