Science Behind Racquets “Wearing Out”

Dlee86

New User
Is there any science or data that support that Racquets “wear out” after a certain amount of years or use or re-stringing?

Unless a racquet has been abused (keeping in car in extreme hot or cold) I find it hard to believe that the molecular structure of the Racquet could change.

I think that Big Racquet has spent lots of money trying to convince us that our old racquets need to be replaced.
 

Mark-Touch

Hall of Fame
Is there any science or data that support that Racquets “wear out” after a certain amount of years or use or re-stringing?

Unless a racquet has been abused (keeping in car in extreme hot or cold) I find it hard to believe that the molecular structure of the Racquet could change.

I think that Big Racquet has spent lots of money trying to convince us that our old racquets need to be replaced.
No science behind that at all.
I have vintage rackets from the 60's and 80's that are doing just fine, thank you very much.
 
D

Deleted member 776614

Guest
I realize this doesn't address the numerical part of the question, but the science behind it would be the epoxy becoming brittle, and/or delaminating from the carbon from repeated impact and flexing. How much that happens, when it happens, and how much it would be noticeable is obviously up for debate. Composite structures do break down (separate) when there's movement.

Composite boat hulls and airplane parts last a heck of a long time, so it's not unrealistic to expect a tennis racket to last if it hasn't been abused. But sticks do deform quite a bit when strings are cut, and all that flexing isn't great for the composites.
 
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blai212

Hall of Fame
the racquets do probably deteriorate but my guess is that racquet companies highly exaggerate it so that they can keep up sales of new models or else they’d be out of business…worn down racquets do become softer/flexier over time but probably become noodles over the course of 5-10 years of heavy use IMO
 

jmacdaununder2

Hall of Fame
I've been using the same model Prince Equipe LB MP for a couple of decades; the original two - I have twelve currently - now play with more flex, particularly in the head, but some days this is appreciated, despite a slight loss of power. They were a low 70s ra to begin with though, perhaps somewhat mitigated by the 28" length.
 

socallefty

Legend
I use the same racquet model for 4-5 years and so have to buy new racquets every 2-3 years as I play more than 500-600 hours every year. I can vouch for the fact that a racquet with 300 hours on it plays much softer and less powerful than a brand-new identical racquet when both are strung exactly the same way. This is particularly noticeable on serves where it is harder to adjust the swing speed to compensate for the more flexible, older racquet and my ace rate and service hold-% goes up with new racquets.
 

colan5934

Semi-Pro
If you're a recreational player who mostly hits live balls in drills or matches 2-3 times a week, then you probably won't have a problem or notice a difference even after many years. The changes are so gradual and lower in magnitude for players fitting that description.

If you're a high level player--ranked junior, college, or higher--there's a lot more wear and tear on racquets. Stringing beats them up, stiff strings wear the frame down, hitting thousands of balls a day with players who hit the ball hard and heavy breaks the carbon down, and contact with the ground just happens for a lot of players digging out balls on the run. The game is just so much faster and more powerful at those levels. When I was training for competition, I'd have dead frames every year, sometimes sooner: stringing each frame 2 times a week and hitting daily for 3-4 hours takes its toll. But now, playing people who don't hit as hard (and probably not hitting as hard myself), not practicing, and doing it infrequently, I can use frames for a couple years before feeling the need to replace--I notice a difference after 9 months to a year usually but they're still usable.

As for the actual science, I'm sure there are plenty of articles out there on how carbon breaks down after repeated physical stress if you look. But it's just like anything. If you bend it enough, it will break.
 

ron schaap

Hall of Fame
Is there any science or data that support that Racquets “wear out” after a certain amount of years or use or re-stringing?

Unless a racquet has been abused (keeping in car in extreme hot or cold) I find it hard to believe that the molecular structure of the Racquet could change.

I think that Big Racquet has spent lots of money trying to convince us that our old racquets need to be replaced.
If we are talking about amateurs than racquets dont wear out because of normal use. Its only a hype to sell us more racquets or an excuses for some to buy every year the newest racquet model.
 

pow

Hall of Fame
This is a forum full of racquetholics who will jump at any excuse to buy a new racquet.

Having said that I think my racquet has been feeling a little less crisp from when I bought them this morning. I was giving it the ol heavy topspin forehand during my warmup sesh. Hopefully there's a sale on other racquets soon.
 
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Winners or Errors

Hall of Fame
It's so hard, when manufacturers change molds and compositions and come out with new sticks repeatedly, to say that the racquets I have been playing with for a decade are performing differently than when I first bought them. I mean, what am I supposed to compare them to? It's not like I can go out and buy new ones. I believe that the resins they use in racquets do break down over time, but I have several racquets in my rotation and haven't noticed it. They can't all be changing at the same rate, but they all still play the same relative to each other.
 

ollinger

G.O.A.T.
There would almost be an Intelligent Design, or Hand of the Creator, sense if racquets that were stiff when you bought them at a younger age got more flexible, and easier on the body, as you got older. But having said that nonsense, I will say I know guys who've been using the same racquet for over a decade, sometimes well over, with no discernible fall-off in performance.
 

RVT

Rookie
As for the actual science, I'm sure there are plenty of articles out there on how carbon breaks down after repeated physical stress if you look. But it's just like anything. If you bend it enough, it will break.
Don't want to sound pedantic here, but carbon fibers don't actually "break down". They can break at their yield point, but you're not going to see that unless you smash the racket against something...

What can break down are the resins used to hold it together. This is why a frame can have more flex over time--and there is absolutely change at the molecular level. I'm sure manufacturers have their own internal standards and tests for how many cycles vs % of stiffness lost, but as an industry I don't think that tennis equipment manufacturers have any set guidelines.

I don't really see this as a concern for tennis rackets. Just use it until 1) it feels much more flexy than you like, or 2) it breaks
 

Ronaldo

Bionic Poster
There would almost be an Intelligent Design, or Hand of the Creator, sense if racquets that were stiff when you bought them at a younger age got more flexible, and easier on the body, as you got older. But having said that nonsense, I will say I know guys who've been using the same racquet for over a decade, sometimes well over, with no discernible fall-off in performance.
The guy or the racquet?
 

danbrenner

Hall of Fame
The science is more like marketing propaganda. A racquet can last a lifetime. It’s the grommets and other caps that will rot. But they can usually be replaced
 

Ronaldo

Bionic Poster
The science is more like marketing propaganda. A racquet can last a lifetime. It’s the grommets and other caps that will rot. But they can usually be replaced
Recall when Wilson would send a new set of grommets once-a-year on request. Reminded friends to do this. Rather keep using those old tattered, brittle, broken, trashed bumpers & grommets.
 

WYK

Hall of Fame
I dunno about the science, but the other evening my doubles partner framed a serve return that fracture the hoop. I imagine that racquet is technically 'worn out' now.
 

colan5934

Semi-Pro
Don't want to sound pedantic here, but carbon fibers don't actually "break down". They can break at their yield point, but you're not going to see that unless you smash the racket against something...

What can break down are the resins used to hold it together. This is why a frame can have more flex over time--and there is absolutely change at the molecular level. I'm sure manufacturers have their own internal standards and tests for how many cycles vs % of stiffness lost, but as an industry I don't think that tennis equipment manufacturers have any set guidelines.

I don't really see this as a concern for tennis rackets. Just use it until 1) it feels much more flexy than you like, or 2) it breaks
Maybe a little pedantic but not inaccurate or bothersome. I'm in a habit of dumbing things down so it's easy to understand for my clients, so apologies for the confusion on semantics. But you're right: carbon fibers are stable indefinitely from a molecular standpoint. The thing with racquets, though, is that they're still made by hand. If the resin is applied a little unevenly or a spot is missed, you can have a weak point in the racquet. That, or trauma to the racquet and then repeated stress (stringing, hitting, etc.) will cause it to fail eventually--maybe not on the outside or in every layer. To expect a racquet to never hit anything but a ball is unrealistic...hitting the ground on a slice, clanging with a doubles partner, falling off a bench or cart, etc.

Compression can break carbon fiber over time too, can it not? My education in physics is more along the biomechanics line, so I may be mistaken. The strings sitting in the frame are going to exert a compression force on it almost constantly, no? It's definitely not enough to break the racquet immediately, but over time and hitting repeatedly with high swing and incoming ball speeds the wear adds up. I'm thinking about @J011yroger and his Pro Staff 90s strung with Kevlar as a prime example, though the extent of the damage to those frames is an outlier. The kevlar hardly stretches, so lots the time of the compression force the strings exert on the frame is quite short and the force is greater per second as opposed to a more elastic string.

Again, somebody more well-versed in physics than me would be able to explain this more accurately, and I could be wrong on some or all of how I understand it. It's a stimulating topic for me either way!
 

Hit 'em clean

Semi-Pro
Racquets do wear out... but that doesn't mean you can't play with them still. The most stress you'll ever put on a frame is when it is restrung. The more string jobs the more the racquet will lose its stiffness. So if you have a Pure Drive that you've restrung 30 times and you buy a new one just like it... you'll notice a difference in power, stiffness, etc. Pros change get new racquets because they are constantly getting them restrung and they want 'fresh' frames. Not that they couldn't keep playing with those frames if they wanted, but eventually the frame won't provide the same power/spin, etc. that they expect.

If you like how the old 'worn' frame plays... what does it matter? But the most wear & tear you'll do to it is restringing... outside of not replacing a bumper guard and physically scraping/wearing down the frame itself.
 

RVT

Rookie
Compression can break carbon fiber over time too, can it not? My education in physics is more along the biomechanics line, so I may be mistaken. The strings sitting in the frame are going to exert a compression force on it almost constantly, no? It's definitely not enough to break the racquet immediately, but over time and hitting repeatedly with high swing and incoming ball speeds the wear adds up. I'm thinking about @J011yroger and his Pro Staff 90s strung with Kevlar as a prime example, though the extent of the damage to those frames is an outlier. The kevlar hardly stretches, so lots the time of the compression force the strings exert on the frame is quite short and the force is greater per second as opposed to a more elastic string.

Again, somebody more well-versed in physics than me would be able to explain this more accurately, and I could be wrong on some or all of how I understand it. It's a stimulating topic for me either way!

Carbon fibers in isolation are relatively weak in compression, but you really have to look at the system propert=ies vs. the material property. In other words, the resins do the heavy lifting under compression. The regime of a tennis racket is such that compression forces aren't really an issue here (and the grommets certainly help--take them out of the mix and I'd have a different answer!). Ultimately, resin fracture is really the concern vs. yield of the carbon fibers themselves. And I'd also agree that the moments that are most likely to cause resin fracture occur during restringing.

That said, I don't want to overstate the stresses here. Compare this to say a bicycle, which is seeing far greater forces in multiple planes, and is a far more complex structure. And failure typically involves dental work, lawsuits, and subrogation claims with multiple factories... And yet, the overwhelming majority of carbon frames and forks hold up great unless less-than-ideal circumstances. TL:DR, I wouldn't worry about my racket until is breaks.

Real world experience: I've broken almost every frame I've used, except the ones I have now (which are new). The failure mode (and signs if failure) are almost always the same: starts to feel a bit flexy on balls hit high on the hoop, then soon after exhibits cracking somewhere around 2:00 and 10:00. I've broken some early ones at the throat, but I think this has been resolved long ago on the design side.
 

Hidious

Professional
High-end hockey sticks are made from carbon fiber I believe in a similar way racquets are, and they do wear out rather quick (not talking about breaking them here). Micro-tears happen in the blade of the stick, accumulate, and after a while, the blade becomes softer and less rigid. You can actually flex the blade with your hand and, if you put your ear right next to it in a silent room, you hear a small "crunch" sound every flex. At this point, the stick is still plenty playable, but has lost some of it's "oomph" and continues to deteriorate over time. I'm not expert, but I would think similar tiny residual damage could happen in a tennis racquet. Not really during play though, but during the restringing process.

I think a racquet's "wear" level should not be measured by it's age or playtime but from the amount of restringing it has gone through. But hey, I could be totally wrong here.

Edit: Just read @Hit 'em clean 's post, it's been all been said before :)
 
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