What is inside tennis ball? (video inside)

I know the title of this article is pretty childish. But frankly, did you ever asked that question yourself? The answer is clear in the case of pressurized tennis balls, but what is inside of pressureless tennis balls? I decided to find it out.

Pressurized and Pressureless Tennis Balls

Pressurized (Head) and Pressureless (Tretorn X) Tennis Balls – used tennis balls for our experiment

You do not need many things to find out. I need just the knife, the hand saw, Head Championship pressurized tennis ball and Tretorn X Micro pressureless tennis balls.

What is inside pressurized tennis ball?

Pressurized tennis balls are the most common tennis balls used. They have hollow rubber core filled with air (pressurized air). So I need just a normal knife to cut it. See the video below:

The cut was quick and easy. And I found out what we all already know. There is nothing inside the pressurized tennis balls. Just the pressurized air.

Head Championship Tennis Ball

Head Championship Tennis Ball – Before the cut.

Head Championship Tennis Ball

Head Championship Tennis Ball – After the cut

What is inside pressureless tennis ball?

To find out what is inside pressureless tennis ball was a much tougher task. Pressureless tennis balls are solid inside and the rubber around is much stronger. It was impossible to make a cut just with a knife when holding the ball with a hand as I did with the pressurized tennis ball. I needed clamps and hand saw to cut into the pressureless tennis ball. See the video below:

There was a white smooth powder inside. The white powder is essentially micro cells holding the pressurized air. There should be around 700 million micro cells in every Tretorn X tennis balls (according to manufacturer), but I did not count them.

Tretorn X Micro Pressureless tennis ball

Tretorn X Micro Pressureless tennis ball – Before the cut

Tretorn X Micro Pressureless tennis ball

Tretorn X Micro Pressureless tennis ball – After the cut

Now you all know what is the secret behind pressureless tennis balls. Why they do not lose the bounce, do not flatten at all and tennis ball machines like them. More about pressureless tennis balls can be found here.

Posted in BLOG, Reviews, Reviews and tagged , , , .

Tennis Pro Guru

Simon is the leading editor of TennisProGuru.com from 2015. He is an avid tennis player from age of 5, however, he never reached the pro level. Still, he likes playing tennis on different courts, with different rackets, and against different opponents. In his free time, you can find him watching all possible tennis matches he can find on the web or tv. Challenger or Grand Slam? It does not matter, just tennis matters.

He currently plays with:
Racket: Wilson Shift 99 V1
Strings: Babolat RPM Blast
Grip: Head Xtreme Soft
Shoes: Asics Gel Dedicate 7 (for hard outdoor and indoor courts) & Asics Gel-Game 5 Clay (for clay courts),
Balls: Dunlop Fort All Courts and Head Championship
Bag: Axiom Backpack


  1. I would never think about this…. The secret behind pressureless tennis balls is revealed! Perfect review! Thank you for sharing!

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