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View Full Version : Strings influence on swingweight and balance

TW Professor
03-11-2009, 08:33 AM
A couple of threads recently have been concerned with the effect of strings on swingweight and balance. There are two cases:
1. Calculating the difference of two sets of string that let's say are 5 grams different in weight.
2. Calculating the difference between an unstrung and strung racquet with let's say a 15 gram string.

Below are screen shot examples of how to use the Customization Worksheet to estimate these things.

Case 1: What is difference using a 5 gram heavier string than I use now? Put in the specs of your racquet as it is now strung with the lighter string. Then spread the 5 grams out over the string face. Most of the density and length of string is concentrated in the middle, so put most of the weight there. The string density decreases away from the middle, so add less there. Split the amount evenly on each side of the middle of stringbed (here I chose 21 inches from the butt as about the middle).

http://twu.tennis-warehouse.com/images/board_photos/5.jpg

Case 2: What is the effect of adding 15 grams of string to an unstrung frame? Put in the specs of the unstrung frame. Spread the 15 grams out similar to case 1 (my numbers are just one way you could divide it up--it is going to be guesstimate on your part).

http://twu.tennis-warehouse.com/images/board_photos/15.jpg

The answers won't be exact because you will only be spreading the weight out in an approximate fashion, but it should be close enough for practical purposes.

Pro_Tour_630
03-11-2009, 08:53 AM
professor thanks for the worksheet

when I was questioning string influence on SW many people on this board thought I was crazy. They still do:)

type of string, gauge, tension, method of stringing on what machine all has some influence on SW even if it is minor.

just a note this should also be in the string section as well

sureshs
03-11-2009, 09:10 AM
Interesting

03-11-2009, 09:20 AM
The biggest changes in swingweight and balance caused by strings is the increased swingweight and change in balance caused by poly strings vs other strings. <actually I think Kevlar would add even more>. Poly usually adds at least 5 swingweight points vs a similar guage multi and makes the racquet noticeably less headlight (for those who notice such things).

This is less a function of the weight of a string I feel, and more a function of the lack of elasticity of poly..ie; a typical poly job requires a longer length of string than multi to string a racquet

There is something about distributing that little bit extra weight over the entire stringbed that significantly changes the swingweight

Pro_Tour_630
03-11-2009, 09:37 AM
The biggest changes in swingweight and balance caused by strings is the increased swingweight and change in balance caused by poly strings vs other strings. Poly usually adds at least 5 swingweight points vs a similar guage multi and makes the racquet noticeably less headlight (for those who notice such things).

This is less a function of the weight of a string I feel, and more a function of the lack of elasticity of poly..ie; a typical poly job requires a longer length of string than multi to string a racquet

There is something about distributing that little bit extra weight over the entire stringbed that significantly changes the swingweight
correct, may add that extreme difference in gauge will add more SW especially when going from a tnt 18g 1.17mm elastic synthetic at high tension to a 15L BB 1.38mm Poly at low tension, even though it is not the norm a change this extreme will have very noticeable difference in SW and balance.

no Kevlar is a twine, my 18g kevlar weigh nor more than my other 18g synthetic strings around 12grams at normal ranges, not sure about other gauges or extreme tensions

Rabbit
03-11-2009, 11:31 AM
As an experiment, I restrung one of my AG100s. Prior to restringing, I weighed it on digital scales. It was strung with a 17 gauge multi. I installed a 16 gauge multi. After restringing, it weight +2 grams.

Pro_Tour_630
03-11-2009, 11:34 AM
^^^ correct 2g is normal on an open mid, try it on lets say an OS or a dense MP and it is more 3g+

In a blind test I can tell the difference between 5g's spread out in the hoop for sure, as for 2-3grams it is tricky, that is like saying can you tell the SW difference between two identical frames if one had a dampener or not? the location is centralized, very hard to tell, I can't in a blind test, maybe some can.

I am most sensitive to gauge in terms of feel,

Rabbit
03-11-2009, 12:41 PM
^^^right..

From my own experience, I have never seen anyone who can tell the difference, blindfolded, between two rackets strung with different gauges or bearing a dampener.

To be honest, I don't know of anyone who can tell the difference in their frame by string. In other words, if you took someone and blindfolded them, restrung one of their rackets with a poly, I don't believe they could consistently tell the difference between 3 frames all alike.

I do agree with your gauge assesment, I appreciate the differences in gauge as well.