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View Full Version : question about racquet customization - static weight, sw, balance

treblings
11-07-2012, 05:14 AM
if two racquets have the same weight and balance point, their swing weight should be identical? true or false:)

TennisCJC
11-07-2012, 06:13 AM
False. SW is determined by how the weight is distributed along the length of the racket. Weight at the tip of the head has a much bigger impact than weight in the middle of the racket. A very polarized racket with more weight at the tip of the head and tip of the handle would have a higher SW than a depolarized racket with weight more in the middle of the racket. But, the static weight and balance could be exactly the same for the polarized and depolarized rackets.

treblings
11-07-2012, 08:50 AM
False. SW is determined by how the weight is distributed along the length of the racket. Weight at the tip of the head has a much bigger impact than weight in the middle of the racket. A very polarized racket with more weight at the tip of the head and tip of the handle would have a higher SW than a depolarized racket with weight more in the middle of the racket. But, the static weight and balance could be exactly the same for the polarized and depolarized rackets.

thatīs a clear answer, and it makes sense. thank you for that.
may i take this a step further. what if i have bought two racquets. same model, as i want a backup that is identical. same weight and balance. do i have to worry about the swingweight? since itīs the same model

ChicagoJack
11-07-2012, 08:52 AM
Yup, TennisCJC is correct. There are multiple ways to get the same balance point.

Racquet A is : ••••=== ------------------- ••••

Racquet B is : ======---••••••••------------

In the example above, both stock frames started out with the same balance point and total mass.

Racquet A, had another 4 grams of silicone injected into the pallete, and 4 grams of lead added at the tip.

Racquet B, had 8 grams of lead tape added right at the balance point in the throat. Because the lead is centered on the bal point, the balance does not change.

Racquet A, has the higher swingweight as a result of the concentration of lead in the tip.

-Jack

JohnB
11-07-2012, 09:13 AM
thatīs a clear answer, and it makes sense. thank you for that.
may i take this a step further. what if i have bought two racquets. same model, as i want a backup that is identical. same weight and balance. do i have to worry about the swingweight? since itīs the same model

Chances are that the swingweight could also differ a bit.

ChicagoJack
11-07-2012, 09:29 AM
Treblings -

Swingweights can vary quite a bit from one racquet to the next within the same model. In fact, its safe to assume that unless the frames have been tuned up by somebody who knows what they are doing, they probably wont match. If you purchase 2-3 new frames directly from a retailer, and it turns out they all match each other with regards to SW, mass and balance, you should buy a paycheck's worth of lottery tickets because that day is a very lucky day indeed. Creating frames from raw sheets of carbon fiber prepreg, is quite a long process, and consistent QC on the manufacturing side is a very tall order.

-Jack

treblings
11-07-2012, 09:35 AM
iīm not sure i like the answers:) makes it more complicated i guess
so the only way to recognize the difference in sw is this one method where you count how fast a racquet swings, right? that always seemed imprecise for me.
or is there another way to measure swingweight?

ChicagoJack
11-07-2012, 10:42 AM
iīm not sure i like the answers:) makes it more complicated i guess
so the only way to recognize the difference in sw is this one method where you count how fast a racquet swings, right? that always seemed imprecise for me.
or is there another way to measure swingweight?

Hi Treblings -

If you want to use the stopwatch and count the swing method, it's best to count 20 or 30 for better accuracy, and adjust your multiply factor from there. Btw, I recco you do this at a time when your wife, gf or bf is not around, as you will likely get an earful of teasing with the process lol.

There is a smart phone app for measuring sw, but I could never get it to work right. I've no clue what I was doing wrong, as it seems many here have used it with good success. The app was created by Sten Kaiser, he actually posts here on occasion. If you do a search, you'll find there's sh..t ton of threads on that app.

-Jack

treblings
11-07-2012, 12:23 PM
Hi Treblings -

If you want to use the stopwatch and count the swing method, it's best to count 20 or 30 for better accuracy, and adjust your multiply factor from there. Btw, I recco you do this at a time when your wife, gf or bf is not around, as you will likely get an earful of teasing with the process lol.

There is a smart phone app for measuring sw, but I could never get it to work right. I've no clue what I was doing wrong, as it seems many here have used it with good success. The app was created by Sten Kaiser, he actually posts here on occasion. If you do a search, you'll find there's sh..t ton of threads on that app.

-Jack

thanks for the great info, Jack:)
my wife knows better than to tease me, sheīs a tennis player herself.
iīll check out the app and start measuring my frames(and hers as well:))

regards, treblings

uk_skippy
11-07-2012, 02:51 PM
Chances are that the swingweight could also differ a bit.

That can be an understatement. I checked a players rqt at a tennis academy I work with and there was a 12pt SW difference. between the 2. I also checked 3 other rqts for another play 1 was @ 281, the next was 288; and the 3rd was 293.

Regards

Paul

royroy85
11-07-2012, 05:13 PM
That can be an understatement. I checked a players rqt at a tennis academy I work with and there was a 12pt SW difference. between the 2. I also checked 3 other rqts for another play 1 was @ 281, the next was 288; and the 3rd was 293.

Regards

Paul

These are unstrung SW? Would you mind mentioning the models?

uk_skippy
11-07-2012, 11:52 PM
These are unstrung SW? Would you mind mentioning the models?

In the 1st scenario I mentioned the rqts were Wilson and strung in the same string, in the 2nd they were Babolat and unstrung.

In my experience most rqt brands don't have brilliant QC; and I suspect that they aim to get weight & balance close to their tolerance levels. I doubt SW isnt checked, probably due to cost and the target specs will give SW somewhere in the same region; but ultimately it doesnt.

Regards

Paul

treblings
11-08-2012, 12:13 AM
if you have two or more rackets with the same weight and balance and different swingweight, the only way to customize them would seem to be to add weight in different places, wouldnīt it?
is there any secret in how to go about it?

uk_skippy
11-08-2012, 12:36 AM
if you have two or more rackets with the same weight and balance and different swingweight, the only way to customize them would seem to be to add weight in different places, wouldnīt it?
is there any secret in how to go about it?

Yes, you'd need top add weight to the rqt with the lower SW, but then you'd have to add the same amount weight to the other rqt in the right places to maintain the same balance. The issue would be the size of the difference of SW between the 2 rqts. If only a few points, then it shouldnt be too bad; but if its a large difference then its likely to be harder.

The secret is experience in doing this type of work. The more scenarios you deal with the greater your experience grows.

Regards

Paul

xFullCourtTenniSx
11-08-2012, 12:48 AM
thatīs a clear answer, and it makes sense. thank you for that.
may i take this a step further. what if i have bought two racquets. same model, as i want a backup that is identical. same weight and balance. do i have to worry about the swingweight? since itīs the same model

Only worry if you're using a Wilson racket. :cry:

Usually it'll be similar, but it's all on quality control. Sometimes you get unlucky and get totally opposite rackets.

treblings
11-08-2012, 01:20 AM
Yes, you'd need top add weight to the rqt with the lower SW, but then you'd have to add the same amount weight to the other rqt in the right places to maintain the same balance. The issue would be the size of the difference of SW between the 2 rqts. If only a few points, then it shouldnt be too bad; but if its a large difference then its likely to be harder.

The secret is experience in doing this type of work. The more scenarios you deal with the greater your experience grows.

Regards

Paul

thanks, really appreciate you taking the time

i can see, how experience would be crucial. the aim would probably be to achieve the same swingweight without making the racquets too heavy

regards, treblings

treblings
11-08-2012, 01:27 AM
Only worry if you're using a Wilson racket. :cry:

Usually it'll be similar, but it's all on quality control. Sometimes you get unlucky and get totally opposite rackets.

they sold my wife two rackets, blx100, and the gripsize was different. they actually had installed a 3 grip on a racket that was marked as a 2
when our retailer informed them, they told him they had no policy about exchanging faulty racquets.

uk_skippy
11-08-2012, 02:26 AM
thanks, really appreciate you taking the time

i can see, how experience would be crucial. the aim would probably be to achieve the same swingweight without making the racquets too heavy

regards, treblings

No probs.

If the intention is to match SW, then you'd have to make the rqt with the lightest SW match the other 1st, and then have to re-match the initial higher SW rqt back. You may have to make the lighter SW rqt slightly heavier than the target rqt to allow some space to do the re-match.

Regards

Paul

Torres
11-08-2012, 02:30 AM
Yup, TennisCJC is correct. There are multiple ways to get the same balance point.

Racquet A is : ••••=== ------------------- ••••

Racquet B is : ======---••••••••------------

In the example above, both stock frames started out with the same balance point and total mass.

Racquet A, had another 4 grams of silicone injected into the pallete, and 4 grams of lead added at the tip.

Racquet B, had 8 grams of lead tape added right at the balance point in the throat. Because the lead is centered on the bal point, the balance does not change.

Racquet A, has the higher swingweight as a result of the concentration of lead in the tip. I recall that your swingweight / pivotweight explanation was also very clear.

-Jack

I have to say, Jack, you do explain these sort of concepts very well. I recall that your explanation of swingweight and pivotweight was also 10/10 for clarity.

d-quik
02-25-2013, 01:24 PM
Edit:i don't know how to use the internet

Relinquis
02-25-2013, 02:05 PM
is there a stringing machine that measures swing weight? or a stand alone machine that does this?

if we're spending \$500-600 on three sticks, might as well add a few \$ and be able to measure what we need so they match.

ChicagoJack
02-25-2013, 07:17 PM
is there a stringing machine that measures swing weight? or a stand alone machine that does this?

if we're spending \$500-600 on three sticks, might as well add a few \$ and be able to measure what we need so they match.

Hi Relinquis :)

There isn't a stringing machine that will measure swingweight, but we have four good options at varying price points, ranging from free, to maybe someday, to I'll probably never have one of those in a gazillion years.

1. The DIY method, you just need two pencils, a ruler, a stopwatch, and some patience.
http://twu.tennis-warehouse.com/learning_center/vibration_explanation.php

2. The Racquet Tune and SW App for iPhone. Written by Sten Kaisier, a super cool guy who posts on the forum occasionally. Cost is 99 cents.
http://appmaker.se/?m=6&s=0

3. The Prince Precision Tuning Center. The dealer price for that is about \$1,800 but they are often available on sale or on flea bay for \$1,000 - \$1,200 or so. I've had my eye on this for several years, and would really like to have.

http://i252.photobucket.com/albums/hh11/olmo21/TW%20Forum%20Stuff/SW%20calculations/prince_precision_tuning_center_zps489e3462.jpg

4. The Grand Daddy of them all is The Babolat RDC (Racquet Diagnostic Center) Machine, shown below. List pricing on that sweetie is about \$5,200 US. It can do a few things the Prince machine cannot do, most importantly it can measure the flex on a racquet.

Love this guy's glasses. Rockin the nerd look for sure!

http://i252.photobucket.com/albums/hh11/olmo21/TW%20Forum%20Stuff/SW%20calculations/200605racquet_RDC_zpsbc23ff06.jpg

- Jack

uk_skippy
02-26-2013, 12:18 AM
There is also the Alpha Accuswing 2, which is the only stand alone SW machine.

http://dl.dropbox.com/u/20433765/AccuSwing2.png

\$800

ChicagoJack
02-26-2013, 10:18 AM
^^^ oooh sweet, didn't know about that one, thanks skippy!