Tension loss on Alpha Revo 4000

#1
I recently bought Alpha Revo 4000. Probably strung about 8-10 times on it. This is for personal use only as between me, my wife and my daughter there is enough to justify having a stringer of my own.

I have become reasonably proficient in stringing (from where I started :)). I no longer need to watch videos to start stringing, tie finishing knots and tie starting knots. I do 2-piece stringing on all my rackets. The machine was bought new and has never been calibrated.

Recently, I found out about racquettune and used it to measure the tension accuracy of my stringing jobs. Needless to say, I am disappointed. Since then I have also found out about inherent tension loss in a CT machine.

Here are some situations that I would love to get some help on in fixing / understanding:

* Strung Solinco TB 17 @53lbs on a Juice 100 (100 sq in). Immediately after stringing racquettune shows 44lbs. One day later, and playing for 2 hours, racquettune shows 40lbs. Two days later, and playing for 5 hours, it shows 39-40lbs.

* Strung Technifibre X-one biphase 17 @ 60lbs on a APD GT. Immediately after stringing racquettune shows 52lbs. One day later, and playing for 3 hours, it shows 48lbs.

I used racquettune values from the database for string factors for these strings.

Some questions:
* Any recommendations on what stringfactor values are appropriate for these strings ?
* How accurate is the tension reading on racquettune ?
* Is the observed drop in tension on CT expected ? Do I need to compensate by raising the stringing tension ? Can that damage the strings (like going from 53 --> 60 for TB 17) ?
* The machine was brand new. So even though I haven't calibrated it, I am thinking that it is not too off. I have ordered a weighing scale to calibrate it, so will be able to do that in ~1 week.
* Any stringing advice to reduce drop in tension ? I am somewhat slow in clamping, which could be causing steeper tension drop ? Is there a way to compensate for this ? Not sure if my speed in clamping will go up.
* I read that I should pull tension slowly, and did do that. How long should the tension be pulled for ?
* I am getting a racket professionally strung, and going to measure it with racquettune to see the difference. That should tell me if this is an accuracy issue with racquettune or my stringing job.

Thanks.
 
#2
on a lockout machine it would not make any difference how fast you clamp the string. if you want a higher readings increase your reference tension. if you want better tension maintenance double pull each string.
 
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#3
Thanks for the tip. Some clarifications:

* Can increasing reference tension damage the string ? Specifically TB 17 or TB 18, going from 53 -> 60. What about syn-guts ? Should those have a similar reference tension increase (I will soon switch to hybrid strings).
* Double pull means what ? Pull tension. Release lock. Pull tension again. Why does this help with tension maintenance ? Should this be done for both mains & crosses ?

Thanks.
 
#4
Pulling twice will get your final tension closer to ref tension when you take the frame off the machine. On a LO, the string starts to relax as soon as the machine reaches ref tension and locks out. By pulling twice, you are removing more of the static tension losses. CP machines will remove the static tension losses just by pulling a longer time at ref tension until you clamp. That is why your RT tensions are so much lower than ref tension.

You can use the DB values for string factors or use your own. The RT guide has instructions on how to do this. FWIW, I use my own and will have RT tensions ± 1# max different from ref tension.

If your frame is going to be strung by a shop, find out what they use. If they use a CP, it will feel tighter because there will be less tension loss from string relaxation. If they use a LO, ask them how fast they crank and clamp. Just have to be consistent.

If you continue to use your LO, increase ref tension incrementally by 2 or 4# until you find a final tension you like as measured by RT.
 

gmatheis

Hall of Fame
#6
@forty_love Like @10shoe said what matters is if you like the results.

Use racquettune with a grain of salt. Use it to keep track of tension loss, or to work on your consistency when stringing (i.e. strings come off stringer at similar tension time after time) but don't worry about trying to make it read 53 lbs just because that was the reference tension you strung at.

Also every combination of a specific racquet and specific string can alter racquettune's readings. So you cant really compare the reading with hyper-g to a reading with cyclone.
 
#8
* I specified the rackets and the strings that I used in RQT. Hopefully, that will take care of string / racket variations. Although I think all it is looking at is really head-size & string factor.
* I hit with the Juice 100 / TB 17 racket, and it didn't feel as good as in the past. These strings feel very crisp. This time they felt quite muted. Balls were not flying or anything like that. It was quite windy so not sure. My other racket from pro-shop will come tomorrow, so hopefully I will be able to compare (although it is going to be sitting in shop for 1 day).
* I strung APD with RAB Monoflex (the string didn't have a gauge listed). Never used these strings before. These came with the stringing machine. I pulled tension twice as suggested earlier. Set the reference tension high 60lbs (it is a soft poly) for APD recommended tension range 55 - 62. RQT showed 55lbs for a generic poly 16g string (no way to select RAB Monoflex in RQT). Hit with it today, and really liked the result. Will check the tension drop tomorrow, didn't get around to doing it today, and update the thread.

May be the solution is as suggested earlier (1) raise the reference tension by 2lb increments until happy with the result (2) pull tension twice. Hope the string is ok with peak tension of ~59-60.
I am not a fast stringer. It took me 1:20 for me to string with pulling the tension twice. Amazingly enough this was my fastest time :) so I can live with it :)
 

dak95_00

Hall of Fame
#10
I had high hopes for this thread when he started with such a reasonable sentence about only needing a Revo for the three of them.

I’m surprised someone hasn’t told him to sell it and buy a Barairdo, Sensor, or Ghost 2 to get ‘better’ results.

To the op:
Just play! No one has time to pull every string twice! That’s just insane! Change your tension! Change your string!
(You are entering into a black hole. There’s no perfect answer to the question you seek to answer just as there’s no perfect racquet or string either. You are now beginning to chase your tail like a crazy dog if you need a visual. Others will say there’s a solution but the reality is that just changing and tinkering with the tension until you get the feel you like is the only solution. Only you will know. Of course, you’ll be your worst critic. It’s like a blemish anywhere. You’ll know it’s there and the rest of the world won’t notice or care. Are the other two complaining? If not, don’t say a word! If they are, adjust the tension higher or lower until the complaints cease.)
 
#11
No one has time to pull every string twice! That’s just insane! Change your tension!
I assumed that was out of the question.
I’m surprised someone hasn’t told him to sell it and buy a Barairdo, Sensor, or Ghost 2 to get ‘better’ results.
That’s true but there are two issues is and it seems the primary problem is tension maintenance. Easy enough to adjust tension until you get what you want and play but that’s too simple for most of us. You’re not going to improve tension maintenance on a lockout with extra work.

While I agree one can get the same results on a $200 machine or a $8,000 machine there is still a huge difference.
 
#12
A few years back I went from a Gamma 6004 with a Wise tension head to a Star 5. The Gamma / Wise was a great combination. I string 2 similar rackets with the same string, one on the Gamma / Wise and the other on the Star 5. I calibrated both machines to pull at the same tension. The racket string on the Star 5 was tighter by a couple of pounds straight off the machine and had better tension maintenance (lost less tension over time.) The only things I can attribute the difference to was the overshoot on the Star 5 was greater, the stiffness of the turntable, and the clamps.

Assuming the OP wants to keep what he has I’d say to just work for what feels good and forget the numbers.
 
#13
The NUMBER is just that--a number. It's a reference number. If you're stringing at 50# and you or the customer likes it, then you discover via you RacquetTune that it's only 44#, why would you change it. If you, or you customer, think the string is too loose, go up in tension. But not because the RacquetTune suggests it was too loose. Do it when you feel during play that its too loose. RacquetTune has only created doubt for you, psychologically making it too loose. If you'd never checked it, what tension do you play best with? Go with that.
 
#14
The main reason I am worried about the number is that polys are not supposed to be played at high tension to avoid arm injuries. So if the string is tight, and RQT is reporting low number then I don't wnat to raise it just for RQT. As suggested, perhaps the right tension has to be discovered empirically.

To complete the loop on the earlier point, RQT is unable to measure the tension of the professionally strung racket. This is most surprising, and annoying. It can still measure tension on the racket that I strung.
 
#16
Yes used compatible units. The racket setups are identical. Both rackets are Juice 100. Both strings are TB 17. Both were strung at 53. One by me, and other by pro. I am using a spoon to hit the strings. At this point both rackets have been hit with. One for 5 hrs (my string job), other for 2 hrs (pro string job). And strung for at least 2 days.

My string job shows ~40 quite consistently when hit in center. It read 44 straight off the machine, and then dropped to 40 after hitting once. It hasn't changed since then.
Pro string job shows no tension when I hit in the center.I tried hitting at other places in the racket. And these are producing readings between 38-42. I didn't have a chance to perform RQT reading on a racket not hit with.

So my takeaways for now are:
- Calibrate the machine
- Double pull tension (I know you guys think its time consuming, but I am only stringing 1-2 rackets / week). I noticed pulling tension 2nd time removed some more slack (not sure if that was indeed the case, or me imagining things).

I am not planning to raise tension to satisfy RQT readings. Will do that if the racket feels loose. Currently the balls don't fly off or anything. So no reason for now. May be the RQT setup is not correct, the string factor is not correct, or some other issue.
 
#17
That’s true but there are two issues is and it seems the primary problem is tension maintenance.
It sounds to me from his first post that the problem with tension maintenance came about when he started to use racquettune, he never said that he was losing playability after X hours of play.

If the OP starts to not like the way his strings play after a certain point, THEN he could use Racquettune to establish when that is and also look for ways to increase tension maintenance (double pulling). But until the OP establishes that he feels a loss of playability this is mostly in his head after seeing numbers from Racquettune and should probably be ignored.
 
#18
It sounds to me from his first post that the problem with tension maintenance came about when he started to use racquettune, he never said that he was losing playability after X hours of play.
That's what i meant. RT did not measure what his stringer was set to (tension) and the tension fell off faster than he thought it should have (tension maintenance.) if the OP didn't have RT he would probably be happier.
 

elkwood

Hall of Fame
#21
As u get better at stringing u will develop the habits that promote good tension maintenance. I backed off from
60 on my mains with gut to 56. The last time at 58 i felt the string bed was just to tight. Its over me developing
a better method of stringing on my machine A stringway. I work my crosses as i pull pull tension i move the mains around and half a dozen other
little things i don't think about that have promoted a tighter string bed.Its how i clamp now vs when i started and the big one is way better at tying
knots. I don't loose tension like i use to when i first started.

I say that as u increase your number of rac strung u will get to where u want to be .
 
#22
I got my weighing scale, and used it to calibrate my machine. I tied two Solinco TB 17 strings to two ends of the weighing scale and used starting knots. Tightened the knots by pulling tension. One end was attached to clamp, by keeping the turntable perpendicular to the gripper. Turns out my machine is reasonably calibrated. After pulling tension for a few times, they were showing tension fairly close to what was configured.

After lock out, I noticed that the tension drops continuously (as expected with a LO mechanism). Here were my tension readings after 10 seconds (approx amount of time needed to attach the clamps):

Configured tension -----> Tension reading after 10 seconds
=======================================================
48 ----> 43.75
51 ----> 44.75
54 ----> 47.25
57 ----> 50.45

Some conclusions based on this observation:

* I think it does matter how long it takes to clamp after pulling tension. The sooner you can attach the clamps, the lesser the tension drop. Although I have no idea what happens to tension once clamps are attached.
* I don't think pulling tension twice prevents the drops as I was using the same string for all my measurements and still saw the drops. So I don't understand why pulling tension twice helps in tension maintenance ?
* For my setup, I should probably be using reference tension between 54 - 57.
* The drop might be different for different types of strings. I didn't measure this.
 
#23
As u get better at stringing u will develop the habits that promote good tension maintenance. I backed off from
60 on my mains with gut to 56. The last time at 58 i felt the string bed was just to tight. Its over me developing
a better method of stringing on my machine A stringway. I work my crosses as i pull pull tension i move the mains around and half a dozen other
little things i don't think about that have promoted a tighter string bed.Its how i clamp now vs when i started and the big one is way better at tying
knots. I don't loose tension like i use to when i first started.

I say that as u increase your number of rac strung u will get to where u want to be .
That's right. If the machine you mentioned is a LO, then it seems to me that speed of clamping probably has a huge impact on tension bed tightness. You guys are probably very efficient in clamping, which is why the tension drop is negligible for you (I take my sweet time in clamping :) something that I will look to change).
 
#25
Just the opposite on a LO machine speed of clamping makes very little difference.
Tension steadily drops when LO mechanism is engaged (as measured by the weighing scale). This continues for almost 40-50 seconds, which is why I suggested that speed of clamping probably matters. Can you educate me as to why speed of clamping doesn't matter for LO machines.
 
#26
Tension steadily drops when LO mechanism is engaged (as measured by the weighing scale). This continues for almost 40-50 seconds, which is why I suggested that speed of clamping probably matters. Can you educate me as to why speed of clamping doesn't matter for LO machines.
What do you think happens when you clamp the string? Whether you lockout and hold the tension with a tensioner or a clamp tension drops.

EDIT: There is a difference with the tensioner because the LO spring holds a little tension that a clamp will not.

EDIT: You can try this left the machine lockout and mars the string going into the grommet to the tensioner. I will never move. The string relaxes and looses tension but that length of string remains the same. On a CP it’s different, as the tension relaxes, the tensioner pull again and stretches the string more. A LO doesn’t it locks out.
 
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#27
After lock out, I noticed that the tension drops continuously (as expected with a LO mechanism). Here were my tension readings after 10 seconds (approx amount of time needed to attach the clamps):

Configured tension -----> Tension reading after 10 seconds
=======================================================
48 ----> 43.75
51 ----> 44.75
54 ----> 47.25
57 ----> 50.45
Perhaps I'm mistaken, but it sounds like you're not calibrating in the correct manner.
While calibrating, you don't move any clamps at all. You don't "attach" them, "unattach" them, or reposition them at all.
Now... you do secure the string (coming from the calibrator) within a machine clamp, but that's before you pull tension and take the reading (which should be done right away... not several seconds after reaching lock out).

Also (just in case you're running any of these strings through a racquet/grommets), the calibrator's strings should run through absolutely nothing.
If you run the calibrator's strings through a racquet, you are introducing lots of friction into the equation and it will make your readings lower than they should actually be.
You don't even need a frame mounted, at all, to take the calibration readings.
Additionally, the clamped string (in the machine's clamp) needs to be held up - to the same height that the other string (opposite side of calibrator) enters the tension head. Both strings (and, therefore, the calibrator) should be level.

Were you routing the strings through a frame?
 
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