Balance / swingweight question

[T-Vex]

Recently I've been learning a lot about swingweight of rackets, and what is it useful for in tennis, but one thing Im not ceertain I got right is - balance and it's role.

From what I've read, balance has a direct influence on racket's swingweight, but somehow it is possible not to change the balance point of a stick, but to increase the SW.

To me that sounds a bit contradictory - if a lower SW racket is more manouverable, wouldn't "heavier" racket then feel less manouverable?
What would be the logic of incresing rackets SW for, say 15 kg/cm2, and pertaining the same balance point?

Or does "manouverabilty" stand for something else?

TY

 

[Bowtiesarecool]

Swingweight is a standardized measurement of how difficult it is to accellerate a racquet about an axis, (Babolat RDC uses 10cm from the butt). The balance point tells you where a racquet's center of mass is. The closer to your hand, the easier it is to maneuver. It also has the effect of reducing the handle's tendency of wanting to pull out of your hand when hitting a ball. Now, you can have two racquets with greatly different balance points but the same swingweight. I'll give you an example: Racquet A has a swingweight of 320, weighs 10.6oz strung, and a balance point of 13" fro the butt. Racquet B also has a swingweight of 320 but weighs 13oz and has a balance point of 11.5" from the butt. As you can see, Racquet B while being a great deal heavier than racquet A, is just as easy to get the head moving, and with a very head light balance, will be just as easy, if not easier to get back and into position. Read this: http://racquetresearch.com/sevencri.htm There are a few minor things it doesn't adress, but it covers in detail everthing i just said.

 

[T-Vex]

Yes, I understand all that (and have read that fantastic page!), but that still doesn't clarify to me the difference between "manouverability" and "swing weight". :-?

What bothers me actually is - what is the another effect of the balance, if swingweight is a direct function of balance.

I've many times seen people in these forums use terms "swingweight" and "manouverability" as synonyms, but somehow I doubt this is correct.

For example, I would want to have a harder to swing racket than I currently have (because I dont like the output speed and "heaviness" of my balls), but would like to keep the current balance as it is (7-8 pts HL), so racket could keep it's "manouverability".

TW racket customization tool can make a computation that enables to achieve exactly that - but the problem is: how could my racket feel as manouverable as before if it would, at the same time, feel heavier to swing???

IE:

I guess the only explanation would be: manouverability and swingweight are two different terms that have their respective functions!

 

[blipblop]

This issue is the single most misunderstood aspect of racketry, in my opinion. Let me take a shot.

1. SW is not really a direct function of balance. SW is, strictly speaking, a function of the moment of inertia about the axis that would go through your palm as you hold the racket. Balance can be used to calculate/approximate SW, but balance and static weight alone do not yield swingweight.

2. Maneuverability is a subjective term. Usually it is most closely associated with swingweight, but this varies greatly from person to person.


Without going too deeply into solid mechanics and physics, it has to do with the mass distribution throughout the racket. Since rackets are not homogeneous rods, it becomes more complex than just static weight and balance.

I understand what you want to achieve, and it is what many on this forum are looking for: maximum plow through without making a racket unwieldy. The short answer is: there is no magic here, higher swingweight implies more plow through. You cannot "counterbalance" the racket to bring the maneuverability back.

 

[JohnB]

Swingweight and balance are not related.

I think the difference between swingweight and maneuverability is that swingweight tells you how hard it is to swing and maneuverability gives you an idea of how easy or hard it is to get your racket in position. (I think maneuverability is best felt by how easy or hard it is, putting your racket in position for volleys)

The more headlight the more maneuverable it will feel.

So, if you add weight at the tip, swingweight will increase. If you then counterbalance it will more maneuverable.

 

[ThomasTerrible]

Swingweight and balance are not related.

I think the difference between swingweight and maneuverability is that swingweight tells you how hard it is to swing and maneuverability gives you an idea of how easy or hard it is to get your racket in position. (I think maneuverability is best felt by how easy or hard it is, putting your racket in position for volleys)

The more headlight the more maneuverable it will feel.

So, if you add weight at the tip, swingweight will increase. If you then counterbalance it will more maneuverable.

You can't say that the two aren't related. All other things the same, a headlighter balance means less swingweight.

That said, they're not in direct relation and you can't calculate swingweight simply from static weight and balance, since mass distribution also varies..


Also, we're forgetting an axis of rotation here: manoeuvrability (the world's hardest word to spell) also depends to some extent to the twistweight, since a racket with high swingweight will be harder to get in position quickly..

 

[TimothyO]

Here are two frames from butt to head...

- means area of less mass.
+ means area of more mass.

A = ++----++

B = --++++--

Both have exactly the same total mass and exactly the same balance.

But frame A has more mass concentrated at the head so it has a higher SW than frame B which has its mass concentrated in the throat/middle.

So two frames of the same balance and static weight can have dramatically different SW.

Same goes for stats such as plow through, twistweight, and power...it all depends on how the mass is disributed. My two 200s are about a gram different in static weight and a little less than one point in balance. But their SWs are perfectly equal and, more importantly, they feel virtually identicle on impact with the ball.

I once had two Speed 300s that felt completely different even when I matched SW since they came off the production line radically different.

As for maneuverability, two frames with the same SW can maneuver differently. Sometimes a lower SW frame can feel less maneuverable than a higher SW frame. For an extreme example, take a low static weight, very head heavy frame versus a heavier but very HL frame with a higher SW. Depending on how the frame is designed and manufactured the heavier one might feel more agile.

In the example above frame A might be more maneuverable than B even with its higher SW.

When I've modded frames I've learned that not all mass is equal or useful. You can add mass in areas that don't help you and may even hinder you. And you can add tiny amounts in key areas that have a huge and very positive impact. Numbers provide a reference point and then you need to test and adjust until you find one that helps you rather than hinders you.

 

[JohnB]

You can't say that the two aren't related. All other things the same, a headlighter balance means less swingweight.

That said, they're not in direct relation and you can't calculate swingweight simply from static weight and balance, since mass distribution also varies..


Also, we're forgetting an axis of rotation here: manoeuvrability (the world's hardest word to spell) also depends to some extent to the twistweight, since a racket with high swingweight will be harder to get in position quickly..

I am saying that balance says nothing about swingweight and that swingweight says nothing about balance.

I don't understand what you mean by "all other things the same". If you mean static mass and weight distribution, the endresult would be the same balance and swingweight, I think.

It's perfectly possible to have a more headlight racket with same static mass and a higher swingweight.

 

[T-Vex]

It's perfectly possible to have a more headlight racket with same static mass and a higher swingweight.

Are you sure?
Cause TW's racket customization tools says opposite, I was no how able to achieve more head ligth racket which had higher swingweight than the starting one! :-?

Balance is always moved towards head!

 

[TimothyO]

Are you sure?
Cause TW's racket customization tools says opposite, I was no how able to achieve more head ligth racket which had higher swingweight than the starting one! :-?

Balance is always moved towards head!

That's a completely different issue.

 

[JohnB]

Are you sure?
Cause TW's racket customization tools says opposite, I was no how able to achieve more head ligth racket which had higher swingweight than the starting one! :-?

Balance is always moved towards head!

Looking at your numbers it appears to be true, but if you increase your desired static weight to 375 and lower your desired swingweight to 350, you can achieve a 31.5 cm balance. So you have a more headlight balance with a higher SW. How it plays is a different thing.

Because you have high starting numbers, there's less room for customizing. This can also be a good thing, because you have less mass to add. If you need substantial mass to add, as you have done to your previous racket, it is tricky to get it to feel right.