About Swingweight measurement

[irad98]

I’ve recently entered in the world of racquet customization and don’t have access to an RDC machine, not even close to that, we don’t even have a full pro shop etc. My only option relies on the TWU homemade method and that’s where I’ve been working on.
I am conducting some measurements in order to validate results and to find a right path to customize my racquets. First I’ve got an old Pure Aero Tour (strung but without over and cushion grip)
PURE AERO TOUR
W:312g
B: 34cm
DISTANCE TO FIRST STRING: 65cm
In order to find the 10 swings time I use a camera and a video editor, measuring frame time from 0 to 10 swing. My first result was aprox 13,8s for 10 swings which lead me to a SW of aprox 337. IMO that number was a bit high, since TW presents a 328 SW on the specs of this model.
Next I’ve attached couple coins on the bottom of the racquet and specs were:
W:330g
B:32,2
DISTANCE TO FIRST STRING: 65cm
Time found was very close to first try, aprox. 13,9s and there we have a problem, SW measured was lower then first one, when It was expected to be the same.

I then proced to make couple more measurements using lower strings as pivot points. Hanging the weightless racquet from a 42,2cm lead me to a higher time for 10s (15,9s) and resulted on a lower SW then the first case (closer to TW specs). But then again, when I add weight I get a lower SW.
Last, I have measured one last time with weights but on a even lower string and found results closer to what I expected which was no change on SW. Problem is I had to use a different string to find that and by doing this I think there is no validation on my measurements.
Am I doing something wrong? Should I always measure from lowest possible string? I would be very grateful If anybody could help me on this subject.

 

[anfield]

Try the "Swing Tool" app to compare your method. It's a little more user friendly if you have a tripod for your mobile phone. It does a good job, not sure how accurate, but it's really simple do a few in a row so you have a larger sample size.

 

[irad98]

Will be also testing that today. But as far as I know the methods are kind the same!

 

[esm]

I used the swing tool with iOS on PAT and got the below. I have done a few time and it is the average SW I got

It has fb of multi, a dampener and 70mm thick OG and if I remembered correctly, there are a couple of grams at 7” from butt

Babolat Pure Aero Tour​

344g

32.0 cm

SW 330

 

[Fairhit]

I’ve recently entered in the world of racquet customization and don’t have access to an RDC machine, not even close to that, we don’t even have a full pro shop etc. My only option relies on the TWU homemade method and that’s where I’ve been working on.
I am conducting some measurements in order to validate results and to find a right path to customize my racquets. First I’ve got an old Pure Aero Tour (strung but without over and cushion grip)
PURE AERO TOUR
W:312g
B: 34cm
DISTANCE TO FIRST STRING: 65cm
In order to find the 10 swings time I use a camera and a video editor, measuring frame time from 0 to 10 swing. My first result was aprox 13,8s for 10 swings which lead me to a SW of aprox 337. IMO that number was a bit high, since TW presents a 328 SW on the specs of this model.
Next I’ve attached couple coins on the bottom of the racquet and specs were:
W:330g
B:32,2
DISTANCE TO FIRST STRING: 65cm
Time found was very close to first try, aprox. 13,9s and there we have a problem, SW measured was lower then first one, when It was expected to be the same.

I then proced to make couple more measurements using lower strings as pivot points. Hanging the weightless racquet from a 42,2cm lead me to a higher time for 10s (15,9s) and resulted on a lower SW then the first case (closer to TW specs). But then again, when I add weight I get a lower SW.
Last, I have measured one last time with weights but on a even lower string and found results closer to what I expected which was no change on SW. Problem is I had to use a different string to find that and by doing this I think there is no validation on my measurements.
Am I doing something wrong? Should I always measure from lowest possible string? I would be very grateful If anybody could help me on this subject.

I invested a full day doing measurements with this method, always got high sw no matter how many tamies and variations I used, I think this method is not that accurate.

 

[irad98]

Just to update.
I bought the app and the measurements were more convincing. I got about 327 on the PAT and same result with added weight on handle. But only visible difference I found between methods is that the app has a "Swing Point" entry. Maybe that can have some influence on the results. I will later compare a bit more the results.

 

[esgee48]

Stoneage, the app developer, has a thread where he measured the location of the swing point and its effect on the accuracy of the timing measurement. He found that between 23-25 cm above the balance point minimizes the inaccuracies of timing measurement and you get a stable small range of SW, i.e. ±2. The SW App times the elapsed swings very accurately. That is the easiest part to screw up.

When you added mass to the butt of the handle, you changed the balance point minutely. The balance point enters into the calculation.

 

[anfield]

He found that between 23-25 cm above the balance point minimizes the inaccuracies of timing measurement and you get a stable small range of SW, i.e. ±2.

One thing I'm always confused about is where to put the yellow sensor bar from the app on the handle. Like the bottom of the bar is flush with the bottom of the handle or have the base of the handle in the middle of the bar?

 

[bfroxen]

I started trying to measure swingweight with the TWU method and eventually developed what's shown in this thread. Measuring the period with a stopwatch is hopeless, and even SwingTool wasn't accurate enough. The free "CMV edu" app I mention in the thread wouldn't work the last time I installed it, so I paid for the full CMV app that includes a stopwatch function. I've used this method enough to be very confident in the results.

 

[el sergento]

Here's the thing with SW, your measurements don't have to be accurate, they just have to be consistent. To me, the Swing Tool app is good enough because I can get consistent readings that I can then use as baselines for customization.

In other words, once you have your SW (327-330 in your case), you can now start comparing, customizing, and matching racquets based on that measurement, regardless of absolute accuracy.

 

[bfroxen]

You can deal with inaccuracy if you're willing to match by trial-and-error, but accurate measurements make it much faster. I'm able to measure, adjust weight based on prediction, and re-measure once just to verify. With less-accurate measurements, it took several iterations to get close to a target.