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TTHopeful
05-22-2017, 12:04 PM
Plastic ball vs Celluloid ball rubber wear.

Why does the Celluloid ball have greater friction then the plastic ball, yet the plastic ball still wears down rubbers faster? Bearing in mind both balls also weigh the same and are near enough identical in surface area.

6Finger
05-22-2017, 01:30 PM
Plastic balls surface is rougher, that's why the rubber wear down faster. How come it has lesser friction/spin than, maybe it's similar to racing car's having slick tires.

ajtatosmano2
05-22-2017, 01:43 PM
Maybe you started to use stronger shots?

Baal
05-22-2017, 07:32 PM
Plastic balls surface is rougher, that's why the rubber wear down faster. How come it has lesser friction/spin than, maybe it's similar to racing car's having slick tires.

The spin per se can be explained by the greater size and weight of 40+ balls. These new balls all have more inertia, so you won't get the same angular momentum on the ball, all other things being equal.

I think different plastic balls do have differences in surface roughness that affect how they behave after they bounce, though, and in some cases even how they fly through the air. This also comes into play when they get very smooth from wear.

I definitely have the impression that plastic balls wear out most rubbers faster.

NextLevel
05-22-2017, 07:37 PM
The spin per se can be explained by the greater size and weight of 40+ balls. These new balls all have more inertia, so you won't get the same angular momentum on the ball, all other things being equal.

I think different plastic balls do have differences in surface roughness that affect how they behave after they bounce, though, and in some cases even how they fly through the air. This also comes into play when they get very smooth from wear.

I definitely have the impression that plastic balls wear out most rubbers faster.

But I also get the impression that the increased surface friction and less spin potential make the used rubbers usable for longer. I can loop with rubbers that I would have discarded ages ago with the cell ball. Or maybe my technique is just better and I am overthinking it.

Baal
05-22-2017, 07:40 PM
I can't tell because Karis M simply seems to not wear at all. It is weird. It looked like cheap bad rubber when I first glued it on (the look is deceiving), but it seems to have simply changed at all since early January. MX-P or T05 would be in bad shape by now.

NextLevel
05-22-2017, 07:54 PM
I can't tell because Karis M simply seems to not wear at all. It is weird. It looked like cheap bad rubber when I first glued it on (the look is deceiving), but it seems to have simply changed at all since early January. MX-P or T05 would be in bad shape by now.

Mine looks really bad. But it plays really well.

BTW, it plays extra awesome with Dandoy Bioboost. Don't ask me how I know, I just do. ;)

TTHopeful
05-23-2017, 07:45 PM
The spin per se can be explained by the greater size and weight of 40+ balls. These new balls all have more inertia, so you won't get the same angular momentum on the ball, all other things being equal.

I think different plastic balls do have differences in surface roughness that affect how they behave after they bounce, though, and in some cases even how they fly through the air. This also comes into play when they get very smooth from wear.

I definitely have the impression that plastic balls wear out most rubbers faster.

Ok that makes sense. I feel my rubbers wear out a lot quicker, do 40+ balls weigh more than celluloid balls baal?

fais
05-23-2017, 08:51 PM
The spin per se can be explained by the greater size and weight of 40+ balls. These new balls all have more inertia, so you won't get the same angular momentum on the ball, all other things being equal.


sorry to be pedantic, but a minor correction - i think what you meant to say is that the angular momentum hasn't changed, rather the angular velocity has dipped due to the increase in inertia

ttmonster
05-23-2017, 09:00 PM
They are definitely more rigid compared to their celluloid counterparts , hence reduced distension and reduced spin , from common sense this should result into more momentum transfer into the rubber and hence more wear and tear of the sponge ...


Ok that makes sense. I feel my rubbers wear out a lot quicker, do 40+ balls weigh more than celluloid balls baal?

Archosaurus
05-23-2017, 09:02 PM
sorry to be pedantic, but a minor correction - i think what you meant to say is that the angular momentum hasn't changed, rather the angular velocity has dipped due to the increase in inertia
It's okay, fais.

It rubs me the wrong way too, when people talk about "shifting the mass". What exactly are you taking away and re-attaching somewhere else? :rolleyes:

ajtatosmano2
05-23-2017, 09:35 PM
this should result into more momentum transfer into the rubber

the angular momentum hasn't changed, rather the angular velocity has dipped due to the increase in inertia

Are you sure you don't hit harder nowadays? :D

ttmonster
05-23-2017, 10:10 PM
That is true, because we subconsciously want to generate the same spin as before , but even otherwise I also feel that the wear and tear is more ...

Are you sure you don't hit harder nowadays? :D

laistrogian
05-24-2017, 12:16 AM
I can't tell because Karis M simply seems to not wear at all. It is weird. It looked like cheap bad rubber when I first glued it on (the look is deceiving), but it seems to have simply changed at all since early January. MX-P or T05 would be in bad shape by now.

How does one play with 4 months old tenergy? All my tenergies are pretty unusable for me after 3.5 months as the topsheet pretty much lost its grip

Baal
05-24-2017, 01:11 AM
Ok that makes sense. I feel my rubbers wear out a lot quicker, do 40+ balls weigh more than celluloid balls baal?

Yes. Most celluloid balls were 2.66 g or so and pretty much all were less than 2.70 -- certainly any of the ones ever used in tournaments. A lot of 40+ balls are 2.73 to 2.76. The DHS 40+ balls that first came out (the ones made of celluose acetate) were 2.78!

The lightest 40+ ball is the Nittaku Premium at ~2.68 - 2.69 followed by the new D40+ at ~2.73. It may not seem like much more than celluloid but it makes a difference. Plastic balls also have slightly larger diameter. ABS balls are also harder and presumably deform less on contact. In fact, the increases weight and diameter is why the new balls are called 40+. I think it could increase the wear rate of rubber (also the surface texture and hardness of the new ball).

By the way, ITTF simply says they are enforcing rules on ball weight that were always in place but which they had been lax in enforcing since pretty much forever. They slipped in the increase in size the same time that they mandated the change in material that they attributed to the "impending world-wide shortage of celluloid" which of course, does not exist. The increase in size was because of..... what? To slow the game down more? To reduce the spin? To make the ball easier to see? To try to beat the Chinese? Who knows. They have never given a reason as to why they suddenly found religion on that particular rule that they had never had before.

I think a great deal of what people find different about playing with plastic balls can be attributed to their larger size. Of course, the cellulose acetate garbage is almost never round and bounces low and breaks all the time and is expensive and thankfully we will hopefully be rid of those.

Baal
05-24-2017, 01:15 AM
sorry to be pedantic, but a minor correction - i think what you meant to say is that the angular momentum hasn't changed, rather the angular velocity has dipped due to the increase in inertia

Being pedantic is just another word for being correct. Thanks for the correction.

TTHopeful
05-25-2017, 08:42 AM
Yes. Most celluloid balls were 2.66 g or so and pretty much all were less than 2.70 -- certainly any of the ones ever used in tournaments. A lot of 40+ balls are 2.73 to 2.76. The DHS 40+ balls that first came out (the ones made of celluose acetate) were 2.78!

The lightest 40+ ball is the Nittaku Premium at ~2.68 - 2.69 followed by the new D40+ at ~2.73. It may not seem like much more than celluloid but it makes a difference. Plastic balls also have slightly larger diameter. ABS balls are also harder and presumably deform less on contact. In fact, the increases weight and diameter is why the new balls are called 40+. I think it could increase the wear rate of rubber (also the surface texture and hardness of the new ball).

By the way, ITTF simply says they are enforcing rules on ball weight that were always in place but which they had been lax in enforcing since pretty much forever. They slipped in the increase in size the same time that they mandated the change in material that they attributed to the "impending world-wide shortage of celluloid" which of course, does not exist. The increase in size was because of..... what? To slow the game down more? To reduce the spin? To make the ball easier to see? To try to beat the Chinese? Who knows. They have never given a reason as to why they suddenly found religion on that particular rule that they had never had before.

I think a great deal of what people find different about playing with plastic balls can be attributed to their larger size. Of course, the cellulose acetate garbage is almost never round and bounces low and breaks all the time and is expensive and thankfully we will hopefully be rid of those.

Thanks for taking your time in explaining this to me baal. I bet there were boffins within ITTF who calculated and new exactly what they were doing when bringing in the plastic ball!