Basic swing weight question

[Polotechnics]

Hi folks.

Sorry about this basic question.

Is it okay to offer customers a basic racket matching service?

ie just static weight and balance

Or should you not offer it if you can't deliver a swing weight reading?

Cheers, Paul


Cheers, Paul

 

[Irvin]

It is fine to offer only weight and balance only. If done properly most players are very happy with just weight and balance. More often than not I add the minimum weight to the lighter racket.

 

[Polotechnics]

Thanks so much, for the reply Irvin. You're a gent.

Did my first two this morning for a client.

Didn't charge though.

How much do you guys in the USA charge per frame for weight and balance customisation?

15 dollars per frame? Or less?

 

[Irvin]

I don’t charge as long as they are only matching weight and balance with the minimum weight.

 

[Polotechnics]

Gotcha.

 

[Stringway Official]

Is it okay to offer customers a basic racket matching service?

ie just static weight and balance

Or should you not offer it if you can't deliver a swing weight reading?

I think that it is much better to offer the clients a SW test:

- Because that is what the player actually feels.

- Because it is one figure instead of 2 like with the balance and the weight.

- Because the square of the balance point is in the SW so 10 % difference in balance point differs 20 % in SW

- Because racquets are classified in SW nowadays.

- Because it is very easy to get a SW value with our SW calculator.

- Because it is a very good service for clients when you can adjust the SW of a racquet, which can also be done with the Calculator.

- The online SW advisor generates a SW advise based on play, age, build.


The link is at the bottom of our site we also have a manual. Click on the blue rectangular.

( As a company rep I am not allowed to post links here)

 

[Irvin]

I think that it is much better to offer the clients a SW test:

- Because that is what the player actually feels.

- Because it is one figure instead of 2 like with the balance and the weight.

- Because the square of the balance point is in the SW so 10 % difference in balance point differs 20 % in SW

- Because racquets are classified in SW nowadays.

- Because it is very easy to get a SW value with our SW calculator.

- Because it is a very good service for clients when you can adjust the SW of a racquet, which can also be done with the Calculator.

- The online SW advisor generates a SW advise based on play, age, build.


The link is at the bottom of our site we also have a manual. Click on the blue rectangular.

( As a company rep I am not allowed to post links here)

Don’t want to start a debate but the Stringway SW calculator (https://www.stringwaynederland.nl/SW-TA-online/SwingCalc/index-en.php) uses weight and balance only to determine SW. Using that calculator, if the weight and balance are the same the resulting SW is the same. How can you say one method is better than another?

EDIT: By the way I do not believe it is possible to determine SW from weight and balance alone. If SW, weight, and balance are all 3 matched it would be better than matching any 2 of the specs.

 

[Stringway Official]

Don’t want to start a debate but the Stringway SW calculator

Using that calculator, if the weight and balance are the same the resulting SW is the same. How can you say one method is better than another?

Because the SW calculator calculates with the square of the balance point and supplies one figure.

Ofcourse I expected always the same reply.

The point is:

- That the calculator offers an overall figure instead of 2 figures.

- The calculator makes it very easy to raise the SW by a certain amount.

- The test result of the calculator can be compared with the advise in the SW advsor.

EDIT: By the way I do not believe it is possible to determine SW from weight and balance alone. If SW, weight, and balance are all 3 matched it would be better than matching any 2 of the specs.

No because it seems not clear that there are mechanical formulas for the moment of intertia which are used in the SW calculator.

How could the test results be so close to measurements with $ 2000 SW machines?

The difference of 2,3 % between the RDC and the SW calculator is quite good compared to differences of SW test with different SW machines (as we did).

 

[shadow01]

Interesting discussion - i've been trying to figure out a way to measure my swingweight without any fancy tools or setups. I measured the head weight (154.7g) and grip weight (169.7g) and length (26 7/8" = 68.2625cm) - result was 309 swingweight from calculator. My total weight was 324.62g - so head & grip weight off by 0.22g (maybe within margin of error of scale? or maybe I measured head and grip weight wrong). I also decided to try the calculator using the balance point method and I wasn't 100% sure of my balance point but it is somewhere between 12.75-13". Using 324.62 grams and a range of 12.75-13" balance point - swingweight is 306.63-316.48 - so very sensitive to knowing balance point accurately. I guess I like the head and grip weight method better. 1 question I have however, if comparing to accuracy to the RDC as @Stringway Official mentions - the RDC assumes grip is at 10cm and measures from that point. Does the Stringway calculator do the same? or do those calculations assume the swing is from all the way at the end of the racquet?

 

[Irvin]

i've been trying to figure out a way to measure my swingweight without any fancy tools or setups.

Weight and balance are Static measurements while SW and TW are dynamic measurements. Inertia (SW, RW, and TW) can only be measured accurately if you put the racket in motion.

you could use the TWU swing weight calculator too but you would have to measure the periods with a stop watch or camera. One method can be way off the other takes much longer.

 

[Stringway Official]

My total weight was 324.62g - so head & grip weight off by 0.22g (maybe within margin of error of scale?

It is very important to define the support positions of head and throat. Therefore we use a little disc on the scale. The sum of the head and throat weight should be the total weight.

I also decided to try the calculator using the balance point method and I wasn't 100% sure of my balance point but it is somewhere between 12.75-13".

The inaccuracy of this is that you have to measure the balance point very very accurately because the square of that value is used in the SW calculation.

Does the Stringway calculator do the same? or do those calculations assume the swing is from all the way at the end of the racquet?

Yes pivot point of the SW calculation is the same as in the RDC.

 

[esm]

Don’t want to start a debate but the Stringway SW calculator (https://www.stringwaynederland.nl/SW-TA-online/SwingCalc/index-en.php) uses weight and balance only to determine SW. Using that calculator, if the weight and balance are the same the resulting SW is the same. How can you say one method is better than another?

EDIT: By the way I do not believe it is possible to determine SW from weight and balance alone. If SW, weight, and balance are all 3 matched it would be better than matching any 2 of the specs.

It also let you use the head/bottom weight and length to measure the SW.........

 

[esm]

It is very important to define the support positions of head and throat. Therefore we use a little disc on the scale. The sum of the head and throat weight should be the total weight.

The inaccuracy of this is that you have to measure the balance point very very accurately because the square of that value is used in the SW calculation.

Does the Stringway calculator do the same? or do those calculations assume the swing is from all the way at the end of the racquet?

Yes pivot point of the SW calculation is the same as in the RDC.

I find it can be tricky to get the head and bottom weight to equal the total weight. I usually use small piece of Lego from my kids to measure these two weights.

 

[Irvin]

It also let you use the head/bottom weight and length to measure the SW.........

By using the head and handle weight the StringWay calculator is calculating the balance point for you. Either way you look at it the calculator uses only weight and balance.

Here's an example of what I am talking about. Suppose I wanted to increase the TW and SW of a tennis racket. If I added 2 g of weight at 3, and 2 g of weight at 9, would it be the same as adding 2 g at 6 & 12"? As far as the balance of the racket is concerned on both the horizontal and vertical axis (as long as 3&9 if centered between 6&12) the weight and balance would be identical. Weight at 3&9 increases TW moire, and weight at 6&12 increases the SW more.

 

[Irvin]

I find it can be tricky to get the head and bottom weight to equal the total weight. I usually use small piece of Lego from my kids to measure these two weights.

The racket must be level while making both measurements or you must have perfectly centered between the head and handle supports. The balance point off by a mm and your calculation is off.

 

[shadow01]

Therefore we use a little disc on the scale.

Yeah - I used these dowel things to put on scale and table:

View this content on Instagram

View this content on Instagram

I find it can be tricky to get the head and bottom weight to equal the total weight.

Yeah. My total weight was 324.62 grams. My head weight is 154.7 and grip weight is 169.7 - which is a difference of 0.22g. Getting that down to 0.0g will be tricky I think.

Separately - based on the following review ( https://www.tennis-warehouse.com/reviews/U100CV/U100CVreview.html ) - the unmodified strung swing weight for my racquet is 320. I added 3.8g at 12 o’clock before I took the above measurements and the calculator is telling me swing weight is 309. So I must be doing something wrong!

 

[Irvin]

@shadow01 do you know if your scale is linear from 154.7 to 324.62? If not your 0.22 g could be a linearity error in the scale.

 

[shadow01]

@shadow01 do you know if your scale is linear from 154.7 to 324.62? If not your 0.22 g could be a linearity error in the scale.

Don’t know what this is - how can I check the scale? It is an Amir branded scale ASIN B072FN6ZNP

 

[am1899]

By the way I do not believe it is possible to determine SW from weight and balance alone.

Agree 100%

Don’t want to start a debate

Seems to me it’s not a debate when one party thinks they know everything and spends the entire “discussion” trying to let everyone else know. (And no, I’m not referring to you).

 

[Irvin]

Don’t know what this is - how can I check the scale? It is an Amir branded scale ASIN B072FN6ZNP

You could buy precision weights and weigh them. If you have a 150 g weight that weighs 150 g on your scale you know weights around 150 g are correct. If a 150 g weight and a 100 g weight don’t weight 250 g you know weights in the 250 g area are off.

but if you measure balance with a ruler IMO it is much easier to be accurate. If you‘re measuring the weight of 2 rackets 5-10 g different it is much easier to be accurate since they are both off about the same amount if the scale is off a little or not at that weight.

 

[Stringway Official]

OK guys no problem, use what you believe in.

Maybe “not believing” can mean not being able to understand?

This is the formula which calculates the SW.

SW =(B36+B37)*(B39-B40)^2*10^-3+(B36+B37)*(3*1,5^2+B38^2)/12000

So it is not a 123 calculation with the weight and the balance

We believe that it is very useful tool, as alternative for very expensive machines, to compare racquets and to match racquets.

Have a nice day.

 

[Stringway Official]

Separately - based on the following review ( https://www.tennis-warehouse.com/reviews/U100CV/U100CVreview.html ) - the unmodified strung swing weight for my racquet is 320. I added 3.8g at 12 o’clock before I took the above measurements and the calculator is telling me swing weight is 309. So I must be doing something wrong!

Keep in mind the SW of new racquets can differ considerably.
So the only way to compare with and without weight is to compare measurements.............whatever type.

 

[Return_Ace]

OK guys no problem, use what you believe in.

Maybe “not believing” can mean not being able to understand?

This is the formula which calculates the SW.

SW =(B36+B37)*(B39-B40)^2*10^-3+(B36+B37)*(3*1,5^2+B38^2)/12000

So it is not a 123 calculation with the weight and the balance

We believe that it is very useful tool, as alternative for very expensive machines, to compare racquets and to match racquets.

Have a nice day.

From all the random reading of various threads over years between swingweight and mgr/i, @Irvin is probably the last person I would insinuate "doesn't understand" what he's on about with regards to this.

However with that said, I think we're actually debating here is more accuracy of the measurement vs. the true measurement.

The Stringway calculator will give a fixed value for each and every weight and balance, and will be assuming a set mass distribution throughout the racket, is this accurate? If the racket has that exact mass distribution, then yes; however if it doesn't, then how far off the value is, will be down to how different the mass distribution of the racket will be. I would hazard a guess that the calculator simply splits the difference between polarised/depolarised setups so it's never too far off from either.

 

[Stringway Official]

If the racket has that exact mass distribution, then yes; however if it doesn't, then how far off the value is, will be down to how different the mass distribution of the racket will be. I would hazard a guess that the calculator simply splits the difference between polarised/depolarised setups so it's never too far off from either.

The mass distribution is in the head and throat weight. If the weight is evenly distributed over the length, the head weight would be equal to the throat weight.

Again there must be a reason that the measurements on the RDC and Prince machines and the calculator are not too different to doubt it.

And furthermore:

It is just a free service that we offer like the Tension Advisor. So just use it or don’t.

I am not going to fight all the same arguments from the same guys again that I heard before .

 

[Irvin]

The mass distribution is in the head and throat weight. If the weight is evenly distributed over the length, the head weight would be equal to the throat weight.

Mass distribution is measured by the COM. The torque (mass times radius) above and below the COM cancel each other out. The weight measured at the head and throat will only be equal if the distance from the support point to the COM is the same.

Again there must be a reason that the measurements on the RDC and Prince machines and the calculator are not too different to doubt it.

The racket specs listed on the TW website for racket were measured with an RDC. Look at the first racket in each of the first five manufacturers listed on TW’s site. They are Babolat, Head, Wilson, Prince, and Volkl. Use TW’s weight and balance and the Stringway calculator to calculate SW. Not one is close to the RDC measured SW. they are off by 7-15 SW points.

 

[esm]

The racket specs listed on the TW website for racket were measured with an RDC. Look at the first racket in each of the first five manufacturers listed on TW’s site. They are Babolat, Head, Wilson, Prince, and Volkl. Use TW’s weight and balance and the Stringway calculator to calculate SW. Not one is close to the RDC measured SW. they are off by 7-15 SW points.

to be fair though, the TW RDC SW value is an average of a batch they have in stock.... unless you can do the exact same calculation as TW with a batch of racquets... then i think it is okay to have some differences.

as i have read somewhere... the Wilson QC is +/- 7g for the unstrung weight tolerance.... so if one racquet has all the +7g on the tip of of the head (more HH), what difference in the SW you think it'd be with another Wilson racquet of the same model/size that has -7g and most of its weight is at/towards the handle (more HL)?

i think at the end of the day, especially with the availability of the SW machine and its (high) cost, i believe as long as one use one method "consistently", then one will be able to tinker all his/her racquets with the same method/approach... to get what one wanted/needed. i understand some people may say method 1 is different to/better tahn method 2, but i think i am okay if i use one method (only) and achieve what i need on the court - which is the main reason why we play tennis, for me personally.

however, if someone is supposedly to be running a tennis related business and charges people/customer for a SW measurement/customisation, then someone must use an appropriate device... IMO

/i will get my coat.....

 

[Irvin]

to be fair though, the TW RDC SW value is an average of a batch they have in stock.... unless you can do the exact same calculation as TW with a batch of racquets... then i think it is okay to have some differences.

as i have read somewhere... the Wilson QC is +/- 7g for the unstrung weight tolerance.... so if one racquet has all the +7g on the tip of of the head (more HH), what difference in the SW you think it'd be with another Wilson racquet of the same model/size that has -7g and most of its weight is at/towards the handle (more HL)?

Great question but impossible to answer. I can give you an example of why it is impossible but first I need to know if the total static weight is the same or off by what amount. If the static weights are off is the HH or HL racket the heaviest racket.

i believe as long as one use one method "consistently", then one will be able to tinker all his/her racquets with the same method/approach... to get what one wanted/needed.

I would agree with that. If you use the Stringway method though you're matching weight and balance not SW

i understand some people may say method 1 is different to/better tahn method 2, but i think i am okay if i use one method (only) and achieve what i need on the court - which is the main reason why we play tennis, for me personally.

See post #2

It is fine to offer only weight and balance only. If done properly most players are very happy with just weight and balance. More often than not I add the minimum weight to the lighter racket.

however, if someone is supposedly to be running a tennis related business and charges people/customer for a SW measurement/customisation, then someone must use an appropriate device... IMO

Agreed but that device does not have to cost more than $10. See post #10

Weight and balance are Static measurements while SW and TW are dynamic measurements. Inertia (SW, RW, and TW) can only be measured accurately if you put the racket in motion.

you could use the TWU swing weight calculator too but you would have to measure the periods with a stop watch or camera. One method can be way off the other takes much longer.

 

[esm]

Great question but impossible to answer. I can give you an example of why it is impossible but first I need to know if the total static weight is the same or off by what amount. If the static weights are off is the HH or HL racket the heaviest racket.

lets say, Wilson Blade 98 18x20. - maybe this is something "workable"?
from TW site:

Technical Specifications
Length	27 in	69 cm
Head Size	98 sq in	632 sq cm
Weight	11.4 oz	323 gm
Balance Point	13 in 33 cm	4pts Head Light
Construction	21mm / 21mm /21mm
Composition	Braided Graphite / Basalt
String Pattern	18 Mains / 20 Crosses

Babolat RDC Ratings
	Score	Grade
Flex Rating	62	Range: 0-100
Swing Weight	334	Range: 200-400

Agreed but that device does not have to cost more than $10. See post #10

which device are you talking about?
I'd love to know where I can get a decent iPad (or the same one you have) for around $10. Thanks.

 

[Irvin]

I'd love to know where I can get a decent iPad (or the same one you have) for around $10. Thanks.

Most people have a phone or tablet that can be used and I agree that was not included in the price. But you could just use a watch or video camera.

 

[Irvin]

lets say, Wilson Blade 98 18x20. - maybe this is something "workable"?

OK that will work fine but you mentioned 2 rackets one 14 g lighter at the head than the other. Do they both weigh the same or is there a difference?

 

[esm]

Most people have a phone or tablet that can be used and I agree that was not included in the price. But you could just use a watch or video camera.

yeah, i know what you are saying... but Babolat or Prince didn't ask the end customer to use their own screen for the measure reading though... lol

OK that will work fine but you mentioned 2 rackets one 14 g lighter at the head than the other. Do they both weigh the same or is there a difference?

nah - the difference between the two racquets will be 14g (as per the +/- 7g QC tolerance..).
i think i should have looked for the unstrung spec, so for the Blade 98, the unstrung weight should be 304g... so in the worst case, one can be at 297g and one could be at 311g...

 

[Irvin]

yeah, i know what you are saying... but Babolat or Prince didn't ask the end customer to use their own screen for the measure reading though... lol


nah - the difference between the two racquets will be 14g (as per the +/- 7g QC tolerance..).
i think i should have looked for the unstrung spec, so for the Blade 98, the unstrung weight should be 304g... so in the worst case, one can be at 297g and one could be at 311g...

OK then that simple if the static weight and head weight is 7 g off all the weight must be at 12 o’clock. 14 g at 12 o’clock makes a 45 point difference in SW.

 

[am1899]

Maybe “not believing” can mean not being able to understand?

I am not going to fight all the same arguments from the same guys again that I heard before .

I rest my case.

 

[Tregix]

How could the test results be so close to measurements with $ 2000 SW machines
(...)
The difference of 2,3 % between the RDC and the SW calculator is quite good compared to differences of SW test with different SW machines (as we did).

A side question. Did you ever consider manufacturing and selling a SW machine ?

It would be a piece of cake for you as it is MUCH simpler than a stringing machine. For sure it would not cost 2000€ (I have built one so I know it, it costs me around 100€ in parts) and I think there is a market for that. Many people would be interested I believe.

Edit : I'm surprised that you found around 2% difference between different SW machines (but I believe you). They were probably not well calibrated. They should all be within +- 1kg.cm2 which means +- 0.3%.

 

[Irvin]

Did you ever consider manufacturing and selling a SW machine ?

It would be a piece of cake for you as it is MUCH simpler than a stringing machine. For sure it would not cost 2000€ (I have built one so I know it, it costs me around 100€ in parts) and I think there is a market for that. Many people would be interested I believe.

FYI https://tt.tennis-warehouse.com/ind...-a-racketaholic.347887/page-550#post-14740002

 

[Tregix]

Thanks but the question was for Stringway Official .
... I have the Swing Tool app which I used before making my own SW machine. A great app .

 

[shadow01]

Update on trying to find my swingweight:
Data:
Racquet: Wilson Ultra 100 v2 countervail
String: 18G hyper-g soft
Customization: 3.8g tungsten at 12 o'clock
Weight (post customization): 324.62 g
Balance point: 32.5cm
Length: 26 7/8" (68.2625cm)
Hang point: 10cm
swing point: 10cm

Swingweight calculator - ~309
Swingtool using Irvin video - ~316

I don't know how meaningful that difference is when comparing racquets - but that's my result. That is also within the 2.3% tolerance that stringway official mentioned.

 

[esm]

Is there a SW difference between the hand point @10cm on the top of racquet and the bottom of the handle, if all things equal?

 

[Irvin]

Is there a SW difference between the hand point @10cm on the top of racquet and the bottom of the handle, if all things equal?

That would depend on the balance point. Inertia of a physical pendulum is calculated at the center of mass aka recoil weight. To calculate the inertia @ 10 cm the parallel axis theorem must be used. SW = RW + mr^2 where m is mass in kg and r is the distance from the 10 cm axis to COM. If the distance fro the COM to a point 10 cm from the tip is the same as the distance COM to 10 cm from butt then yes the SWs are the same.

 

[esm]

That would depend on the balance point. Inertia of a physical pendulum is calculated at the center of mass aka recoil weight. To calculate the inertia @ 10 cm the parallel axis theorem must be used. SW = RW + mr^2 where m is mass in kg and r is the distance from the 10 cm axis to COM. If the distance fro the COM to a point 10 cm from the tip is the same as the distance COM to 10 cm from butt then yes the SWs are the same.

Ah yes, good point on the balance point. So does that mean you’d need to measure the balance point the other way around if hanging from the hoop or hanging from the handle at the 10cm point...?

 

[Irvin]

Ah yes, good point on the balance point. So does that mean you’d need to measure the balance point the other way around if hanging from the hoop or hanging from the handle at the 10cm point...?

Balance point or Center of Mass never moves. All points equidistant up and down from the COM have the same exact inertia. For example, If the COM is 32.0 cm, a point 22 cm below the COM and above the COM have the same exact inertia.

 

[shadow01]

Balance point or Center of Mass never moves. All points equidistant up and down from the COM have the same exact inertia. For example, If the COM is 32.0 cm, a point 22 cm below the COM and above the COM have the same exact inertia.

Does your statement assume a 27” racquet or still doesn’t matter. I’m still trying to understand all this. But to @esm’s point - I would think that measuring from the other side would seem to make sense since you don’t know total length?

 

[Irvin]

Does your statement assume a 27” racquet or still doesn’t matter. I’m still trying to understand all this. But to @esm’s point - I would think that measuring from the other side would seem to make sense since you don’t know total length?

Length does not matter. changing the racket’s length when stringing it may compress or expand the length of the racket, but when the length changes the COM changes and so does the SW. because the distance from the 10 cm pivot and the COM changes.

 

[shadow01]

Length does not matter. changing the racket’s length when stringing it may compress or expand the length of the racket, but when the length changes the COM changes and so does the SW. because the distance from the 10 cm pivot and the COM changes.

Ok so if you measure the balance point from the same spot you measure the pivot point - that’s what matters. Did I get that right?

 

[Irvin]

Ok so if you measure the balance point from the same spot you measure the pivot point - that’s what matters. Did I get that right?

Yes. what is needed is the distance between the pivot point and the center of mass. Is the COM is 32 cm from the butt and the pivot point is 10 cm from butt the distance between those 2 points is 22 cm no matter what the racket length is.

 

[esm]

@shadow01 @Irvin
some good points. thanks.

so, with the swing tool app, their guide is to hang the racquet @10cm/whatever the location is at the hoop end. (setup 1)

with Irvin's setup - he hangs the racquet @10cm/whatever the location is at the handle end. (setup 2)

hence my question about the balance point data input to the swing weight app.

so, just grabbed a first racquet i can from one of my bags, a Head PC600 (it is strung/OG'd and modded - but doesn't really matter... imo) to measure the balance point from both the hoop end and handle end. on a table with a hard edge and a metal tape measure. the racquet is 68.5cm in length.

for the above mentioned setup 1 - the hoop of the racquet hangs outside of the table. the end of the handle landed at about 32.2cm

for the above mentioned setup 2 - the handle of the racquet hangs outside of the table. the end of the hoop landed at about 36.0cm.

therefore, what i was trying to say was.... with the guidance from the swing weight app, the balance point data i should use for this racquet should be 32.2cm, whereas if you use Irvin's setup, the balance point data for the app for same racquet should be 36.0cm?

does that sound about right? or am i thinking too much and i should go out and get some fresh air?

 

[Irvin]

with the swing tool app, their guide is to hang the racquet @10cm/whatever the location is at the hoop end. (setup 1)

With the SwingTool app they want to know the distance from the butt to the hang point pivot

with Irvin's setup - he hangs the racquet @10cm/whatever the location is at the handle end. (setup 2)

With my jig I the hang poing pivot is 10 cm from the butt

for the above mentioned setup 1 - the hoop of the racquet hangs outside of the table. the end of the handle landed at about 32.2cm

for the above mentioned setup 2 - the handle of the racquet hangs outside of the table. the end of the hoop landed at about 36.0cm.

Your racket therefore is 68.2 cm long or you measurements are incorrect

therefore, what i was trying to say was.... with the guidance from the swing weight app, the balance point data i should use for this racquet should be 32.2cm, whereas if you use Irvin's setup, the balance point data for the app for same racquet should be 36.0cm?

Incorrect the balance point is the distance from the butt 32.2 cm

 

[esm]

With the SwingTool app they want to know the distance from the butt to the hang point pivot

With my jig I the hang poing pivot is 10 cm from the butt

Your racket therefore is 68.2 cm long or you measurements are incorrect

Incorrect the balance point is the distance from the butt 32.2 cm

if you read my post again, i left some sort of "buffer" regarding my quick measurements...... anyway.... 68.5cm vs. 68.2cm.. you get the idea.

so what you are saying is the balance point is the same whether you hang the racquet at the hoop or the handle? as the distance from top of the hoop to the balance point and the distance from the bottom of the handle to the balance point are different from my above mentioned "about" measurement?

my interpretation of the below is that the hang point is at 68cm and the balance point is at 33.2cm, as the racquet should have hanged with the hoop on the top and the swing weight tool "yellow box" will be catching the handle to measure the swing weight.

with your jig/setup (& using the above same racquet for an example) - it'd be measured "upside down", as the handle will be on the top..... so will you be using the same balance point of 33.2cm?

 

[Stringway Official]

as the distance from top of the hoop to the balance point and the distance from the bottom of the handle to the balance point are different from my above mentioned "about" measurement?

Just one remark about measuring the dimensions:

It is of major importance to measure all distances VERY accurately.

The square of the distances is used in the calculation of the Swingweight.
The measurement error is therefore also taken in the square.

 

[esm]

Just one remark about measuring the dimensions:

It is of major importance to measure all distances VERY accurately.

The square of the distances is used in the calculation of the Swingweight.
The measurement error is therefore also taken in the square.

in the normal circumstance, yes, i agree the measurement must be accurate... however, my "experiment" was to explain/make a point of the different balance measurement maybe required for the swing weight app for either hanging/swing from towards the top of the hoop or the towards end of the handle (or the 10cm location).
i my simple head, i thought the balance point would be different for when the swing location is different, as the object "may" swing differently.... hence the quick/experimental measurement. that was no way VERY accurate to achieve a desired outcome....