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View Full Version : Can someone explain "twistweight"

rallyguy
02-21-2012, 07:46 PM
I see the term on the TW University but not the definition. I have an idea what it means as in the higher the number the more stable your racquet is but if someone can explain it further that would be great. Thanks-

ChicagoJack
02-21-2012, 08:16 PM
- It's a way to measure how much your frame will resist rotation round the long axis. The higher the TW, the more stable the frame will be to both kinds of movement around the long axis (spinning like a top or twisting like a twizzler licorice).

- Couple of visual / conceptual aids for you. Picture a badminton racquet held stationary, in an up right position. The handle is stuck into an apparatus that allows it to spin freely left or right. Throw a tennis ball at the outer edge of the strings, aiming for just the inside of frame. Picture how many times that will spin.

- Now picture a specially made Prince Original Graphite frame in that same apparatus, that weighs 40 lbs., has a 500 square inch head, and is 2 feet wide. It weighs 40 pounds, because there are 15 pounds of lead fishing weights welded to to each side of the frame at 3+9 oclock. Throw a tennis ball at that, aiming for the outer edges of the string bed. Picture the spin, or lack there of. You already know the answer intuitively. Weight at the edges slows things down. That's how figure skaters slow down the spin, by extending their arms out, weight to the edges. So, if you want a high twistweight bang for the buck, you put your lead at 3+9, and on the outside of the hoop.

- On the court, a higher TW feels as is the sweetspot is bigger, or shots just off the sweetspot still kinda go where you intend them to go, or more stable in general.

rallyguy
02-21-2012, 09:38 PM
Thanks for the excellent answer.

klementine
02-21-2012, 09:42 PM
Some good ultra-slow shots at the begining of this vid.....

fuzz nation
02-22-2012, 04:34 AM
All I can say after reading Jack's explanation is that I've GOT to go learn how to weld!!!

ChicagoJack
02-22-2012, 10:38 AM
All I can say after reading Jack's explanation is that I've GOT to go learn how to weld!!!

Ha! lol.... I actually had that same thought too.

ChicagoJack
02-22-2012, 10:44 AM
Some good ultra-slow shots at the begining of this vid.....

Wow awesome vid. Really shows the all the waves of wobbles on impact. The manufacturing process is just extra cool too. Thanks for sharing Klem.

JohnB
08-08-2012, 05:45 AM
Is there a way to measure/calculate twistweight?

ThomasTerrible
08-08-2012, 08:15 AM
Is there a way to measure/calculate twistweight?

Calculating it with great accuracy would be near impossible if you don't know the materials' density in the whole frame. It can be measured though. It's exactly the same principle as measuring swingweight, only you rotate the racket on a different axis. When you compare twistweight and swingweight stats, you get a very good idea of how much easier it is to twist than to swing. It also explains why it's so difficult to get good control and power on off-center hits, since the ball needs so little force to apply a significant twisting force on the racket...

Just for fun: compare the tennis racket to this aircraft: http://upload.wikimedia.org/wikipedia/commons/5/54/Flight_dynamics_with_text.png. If the nose is the handle, twist measures on the roll axis whereas swingweight is measured on the pitch axis. In the swingweight case though, the center of rotation isn't in the middle of the racket but near the handle end...

blipblop
08-08-2012, 08:46 AM
Isn't it just the moment of inertia about the main axis (going through the handle)?

ChicagoJack
08-08-2012, 08:46 AM
Is there a way to measure/calculate twistweight?

Hi John,

Heck yeah. You can start with the published Twistweight specs of your model racquet (an average sampling) when it is in stock form . Then use the Reverse Custom Worksheet Calculator (twu.tennis-warehouse.com/learning_center/customizationReverse.php) to get a pretty good estimate for any lead you add to yer stock set up. 3:00 and 9:00 are the correct lead location for maximizing twistweight.

The Holy Trinity = Swingweight, Recoilweight, Twistweight. Learn them, love them.

http://twu.tennis-warehouse.com/learning_center/customizationReverse.php

Jack

http://i252.photobucket.com/albums/hh11/olmo21/Twistweight.jpg

JohnB
08-09-2012, 12:44 AM
Thanks!

Hopefully these twistweight numbers are pretty accurate. If not, I would like to measure myself. But it would be hard to do that.

ChicagoJack
08-13-2012, 05:25 AM
>>> Hopefully these twistweight numbers are pretty accurate. If not, I would like to measure myself. But it would be hard to do that.

Hi John,

Nah, its no biggie. You can measure Twistweight at home, as long as you dont mind being heckeled for the display of utter geekiness your by wife, girlfreind, or roomie. Its done using a similar hang-swing-count stopwatch method that you use to get a DIY swingweight number.

I think thats the long way around the block tho. The posted numbers are accurate, and u can use the reverse customization worksheet, to figure out any
Tw increases if you lead up the hoop.

-Jack