Head Size And COP

[TennsDog]

I just noticed while looking at my n6.1 95 and PS 6.0 85 that, while 10" is quite noticable visually but not huge, it does make a large difference in the location of the sweetspot. The string pattern itself doesn't even start until a little over an inch further away from the handle on the 85 compared to the 95. I have always kind of wondered why it is considered an advanced spec to be head light, thus lowering the COP. I like to add weight at 10 and 2 in raise the sweetspot a bit. I think that, while the 85 is more head light than the 95, it's sweetspot is actually closer to the tip. This undoubtedly adds to the feel it provides and the playability I experience. I think that's one reason it "feels right" when I pick it up: I can visually see that the stringbed is further away (possibly feel it too). It seems like this would actually give back some of the power that an otherwise low-powered racket lacks (due to hitting at a further distance and lengthening the lever arm). That may be one reason I play so well with it, the sweetspot is actually in the place I usually hit anyway, but that isn't actually the sweetspot on most other rackets of more common head sizes.

I don't know really what I hope to accomplish with this post, just something to think about, I guess.

 

[Midlife crisis]

TennsDog, you say COP in parts your post, and then sweetspot in other places. They're not the same thing, but in well designed racquets they tend to be very closely located. I think that modern tennis racquets, with much more elongated heads and lighter weight, tend to have more of a problem with locating the sweetspot and COP more closely together, which is why older racquets have a feel that is so coveted among many.

 

[Greg Raven]

Also, keep in mind that the COP is calculated by various racquet parameters, none of which is the size of the head.

 

[TennsDog]

Ok, well while they may not be the same thing, I would assume they would be similarly affected by the same changes to racket specs, as would a similar change to both provide the same change in feel or playability.

Oh, and just assume wherever I said COP meant sweetspot.

 

[ChicagoJack]

There are 3 distinct points on the stringbed, that when impact with the ball occurs, these points will have 3 distinct flavors of "sweet".

1. COP - There is the place where the shock and jarring sensation to your hand is the least. That spot is the center of percussion, which you have mentioned. As Greg Raven has already mentioned, the location of the COP depends upon several factors, foremost being the distribution of weight along the frame, as well as how low or high you are gripping the handle.

2. The Node - There are the impact point [actually a curved line] on the stringbed where the amount of vibration in the frame is the least. That point is the node, An impact anywhere on these node will not result in vibration.

3. Best Bounce - Then there is the impact location, that gives the most ball return speed. In geek speak, the coefficient of restitution, is at maximum. This point of maximum power is not a vibration and hand jarring free zone, but it does give the player a satisfying ommph feel. This area is called the best bounce. An important point to remember here is that the best bounce is not fixed and stationary. The best bounce/power location for slowly moving or stationary held frame is towards the throat, but the max power zone shifts towards the tip location for a wristy fast ground stroke or serves. The tip will be a deadspot, giving you the least bounce speed when the frame is moving slowly. When you swing the frame fast, as in a serve, you can get the most ball speed towrds the tip. You could'nt say that with the old woodies, but this is true with virtually all graphite based frames today. Thus for the most power on serve make contact above center of the string bed. For fast, wristy, groundies it is possible that the max power spot overlaps the other two, but for most ground strokes, the max power zone will be below center, and below the other two points.

The marketing departments make the instore POP displays showing the sweetspot to be located in one area. What they are doing is drawing a huge imaginary circle around these three points, in order to keep it simple, allbeit somewhat misleading. Just thinking this might help you illusrtrate your point of questioning more concisely. I think you have the right idea essentially with regard to weight distribution, but the each of the three sweetspots have little to do with string pattern, and the other stuff you mention.

Best regards to you, take care
-Jack

 

[TennsDog]

Even with weight distribution, wouldn't the feeling of sweetspot tend to be located toward the center of the stringbed? So everything else being the same, a racket that is missing a certain length from the bottom of the stringbed will have the sweetspot moved up.

Also, kind of back to my original post, does anyone here break strings below center on a regular basis? I have only ever seen strings broken pretty well right in the virtical center or a little above. I wouldn't think too many advanced players would be making ideal contact below the center of the stringbed.

 

[ChicagoJack]

Even with weight distribution, wouldn't the feeling of sweetspot tend to be located toward the center of the stringbed? So everything else being the same, a racket that is missing a certain length from the bottom of the stringbed will have the sweetspot moved up.

Also, kind of back to my original post, does anyone here break strings below center on a regular basis? I have only ever seen strings broken pretty well right in the virtical center or a little above. I wouldn't think too many advanced players would be making ideal contact below the center of the stringbed.

OY. I never said ideal contact was anywhere. The best bounce/fastest rebound speed point is always moving, based on the speed of the tip. Your point regarding string breakage fits this statement, and doesn't undo it.

-Jack

 

[TennsDog]

When I say ideal contact, I meant with reference to where the player is intending to hit the ball. Some people intend to make contact right in the middle of the stringbed, I intend to make contact slightly above center. What brought this to my attention was when I examined the fraying on my PS 95. The four frayed strings are the dead center crosses, but when I hold that up to my n6.1 95, I find that it is still in my ideal contact point, but slightly above center due to the stringbed extending lower.