RacquetTune reading always higher than machine tension setting... ???

[lemurofdoom]

I am using a Gamma X-ELS (electronic constant pull machine). It seems if i pick 48 lbs on the machine, RacquetTune will read low 50s. I did my wife's racquet at 55lbs, and RT read 61-2 afterwards. I did one last night for a guy we know, at 58lbs set on the machine, and RT reads 64-65!!

I'm not doing anything weird with the string job, just a normal two piece job. This has been with mostly poly strings, except my wife's is syn gut. Any ideas what might be going on? Am I doing something horribly wrong with my settings in RacquetTune? Is my machine that badly mis-calibrated somehow? That would be weird since it's less than a year old and a pretty nice machine... ? I'm a bit at a loss, not sure whether to trust the machine or the app, or neither, and now that I am about to give this racquet back to the other guy I know, I will feel bad if it's truly that far off.

help?

 

[struggle]

Calibrate your machine. (check the calibration)

Than you have at least one "known" value to work from.

 

[pmata814]

Same thing happened to me every time i strung my rebel 98's. it gave me a reading of 4 or 5 lbs higher. Recently i switched to the exo3 warrior and now it gives me a reading 3 lbs lower. I personally don't trust the reading as it could be that the string factor is incorrect. I just use it to track tension loss. (I use a revo w/wise tension head btw)

 

[mikeler]

Each string has a custom string factor that needs to be entered to get the most accurate reading. Look in the program help files here:

http://www.appmaker.se/?m=4&s=4

However, if the "known" weight you are using is your uncalibrated machine, then you don't even know that your custom string factor is correct.

I use the default factors since I don't care about absolute tension, just relative tension loss.

 

[lemurofdoom]

Calibrate your machine. (check the calibration)

Than you have at least one "known" value to work from.

I just ordered a calibrator. Surprisingly not too expensive, so that should at least give me some sense of if the machine is even correct. I guess I assumed it was probably right coming from the factory, and haven't used it a crazy amount in the last 6-7 months... but hey maybe it's wrong. We'll see in the next couple days when the calibrator arrives!

Each string has a custom string factor that needs to be entered to get the most accurate reading. Look in the program help files here:

http://www.appmaker.se/?m=4&s=4

However, if the "known" weight you are using is your uncalibrated machine, then you don't even know that your custom string factor is correct.

I use the default factors since I don't care about absolute tension, just relative tension loss.

Yeah, as you say, I don't personally care all that much about the exact tension, as I've done it the same on my racquets from day one and have been very happy with the results (and they are very much the same every time, whatever the actual measured number is), and my wife has been fine with how hers is strung too. But when a friend specifically requests 58 pounds, I'd like to not be delivering 64 pounds =/

 

[bluegrass_stringer]

Guys, racquettune is not going to give you an exact match of the reference tension. It is mainly a device to track tension loss. I guess what you want is racquettune to give you a consistent number each time after you string a racquet, but there is so much room for error with this app. Better solution is an ERT. String for FEEL instead of trying to match your stringjobs to numbers!! If you like the feel of a certain tension, just keep that tension. If you don't, play around with it.

 

[bluegrass_stringer]

The ultimate measurement would be to put your racquet on a Babolat RDC after stringing to get a stringbed stiffness reading. Of course these machines cost many thousands of dollars, but it pays to know someone with one of these machines. I ordered 2 wilson racquets and the racquet stiffness was off by 7 units...and I felt it ( that was the reason I went to get them measured) I now get my racquets matched on an RDC when I buy them.

 

[lemurofdoom]

Guys, racquettune is not going to give you an exact match of the reference tension. It is mainly a device to track tension loss. I guess what you want is racquettune to give you a consistent number each time after you string a racquet, but there is so much room for error with this app. Better solution is an ERT. String for FEEL instead of trying to match your stringjobs to numbers!! If you like the feel of a certain tension, just keep that tension. If you don't, play around with it.

Yeah, just that it being 5-7 pounds higher than what I set the machine to every single time has me wondering if one or both of them is calibrated poorly. And up until I started doing racquets for some friends who are asking for specific tensions, it wasn't a giant problem for me, as I was just using the feel of it and I was fine with it as is (regardless of whether I'm actually getting 48lbs or 52 technically). But now I feel like I have to get it sorted out—at least get the machine sorted out—and then, as you say, just use RT as a gauge for tension loss. I would be 100% fine with RT always being 5 pounds higher than reality, but I need to at least know that that is the case, and that my machine is actually pulling with approximately the proper tension (mostly so that I'm not stringing other folks' racquets 10% too tight all the time).

 

[mad dog1]

actually, RT is not inaccurate. different racquets, different grommets, different strings all have different different coefficients of frictions which affect the resulting tension.

 

[bluegrass_stringer]

Yeah, just that it being 5-7 pounds higher than what I set the machine to every single time has me wondering if one or both of them is calibrated poorly. And up until I started doing racquets for some friends who are asking for specific tensions, it wasn't a giant problem for me, as I was just using the feel of it and I was fine with it as is (regardless of whether I'm actually getting 48lbs or 52 technically). But now I feel like I have to get it sorted out—at least get the machine sorted out—and then, as you say, just use RT as a gauge for tension loss. I would be 100% fine with RT always being 5 pounds higher than reality, but I need to at least know that that is the case, and that my machine is actually pulling with approximately the proper tension (mostly so that I'm not stringing other folks' racquets 10% too tight all the time).

So it sounds like you just need to make sure your machine is calibrated. That is the best "us stringers" can do. Make sure machine is calibrated, and then string the racquet while trying to minimize frame distortion/damage, and tension loss. But don't try to adjust anything because of RT. It is an app that measures audio frequency and then tries to convert it to a tension. There is lots of number manipulation going on in the app to try to produce an actual tension. So when RT gets a reading of 500 Hz, it produces a tension of 60lbs for example. It is also hard to get the exact same reading from RT each time. If you machine is calibrated, then that is what is important.

 

[lemurofdoom]

So it sounds like you just need to make sure your machine is calibrated. That is the best "us stringers" can do. Make sure machine is calibrated, and then string the racquet while trying to minimize frame distortion/damage, and tension loss. But don't try to adjust anything because of RT. It is an app that measures audio frequency and then tries to convert it to a tension. There is lots of number manipulation going on in the app to try to produce an actual tension. So when RT gets a reading of 500 Hz, it produces a tension of 60lbs for example. It is also hard to get the exact same reading from RT each time. If you machine is calibrated, then that is what is important.

Tension calibrator should be arriving tomorrow, so we'll see shortly! I'll just make sure the machine is right, I don't care about what RT says (aside from just tracking relative tension losses) if I know the machine is right.

 

[GlenK]

I have the same machine and mine runs a little high too. But all I care about is consistency and tension loss.

As long as I'm getting the same, or very close, readings with each string job at the same tension I'm happy. Tension loss seems to be tracked accurately, and I'm within .1/.3 with each string job.

 

[mikeler]

Guys, racquettune is not going to give you an exact match of the reference tension. It is mainly a device to track tension loss. I guess what you want is racquettune to give you a consistent number each time after you string a racquet, but there is so much room for error with this app. Better solution is an ERT. String for FEEL instead of trying to match your stringjobs to numbers!! If you like the feel of a certain tension, just keep that tension. If you don't, play around with it.

The theory is sound. If you follow the methodology to get the custom string factor after you have calibrated your machine, the absolute tension should be within an acceptable estimate. It's just easier to use a generic string factor so you can measure tension loss.

 

[Nuke]

If you set your machine to 48 and string the mains, they will be at 48 pounds. Then you add the crosses, which changes the mains from straight lines to the up-and-down shape around the crosses. The mains now cover a slightly longer distance, and are therefore tighter than they were before you installed the crosses. The final tension is higher on the mains with the crosses than it was when you first installed the mains alone.

 

[lemurofdoom]

Update: Well, I just checked the calibration of the machine with a tension calibrator, and it appears to be perfectly calibrated. I tried pulling at 35, 40, 45, 50, 55, 60, 65, and 70. Each one read exactly as it should on the calibrator. So I guess I'll just carry on as I have been, reassured by the knowledge that I am indeed pulling the proper requested tension, and there's just a difference between an individual string's tension and that of the stringbed overall (as noted a few times above). And for me it turns out that RT just is better as a tool to measure relative changes than to get an absolute measurement.

 

[struggle]

i downloaded RT when it came out.

every now and then it updates.

i never use it, maybe i should.

i just check my machine and use my palm, mostly.

 

[ART ART]

We need String Factor Reading in the Android version!