Tennis Balls

Why Do Tennis Balls Go Flat?

Have you ever grabbed a tennis ball to start a match, only to find it barely bounces off the court? We’ve all been there. Over time, the pressurized air inside tennis balls starts to leak out, causing them to go flat. Let’s explore the reasons your tennis balls lose bounce and what you can do to keep that lively pop in your shots.

The bounciness of a tennis ball comes from the pressurized air inside. This internal air pressure gives balls their speed off the racket and provides the familiar, high-arcing bounce we know in tennis. But over time, this pressurization is lost as the ball gradually goes flat. The rate of pressure loss depends on a few key factors.

Why Do Tennis Balls Go Flat?

Tennis balls go flat because the pressurized air inside the rubber core leaks out over time. Hard impacts during play also accelerate air leakage, causing the balls to lose bounce and speed.

What Causes Tennis Balls to Lose Pressure Over Time?

There are a handful of reasons tennis balls lose their initial air pressure and go flat after repeated use. Understanding what’s happening inside and outside the ball gives insight into maximizing ball life.

The Natural Rubber Core Loses Elasticity

The core of a tennis ball is made of natural rubber which gives the ball its bouncy, elastic properties. This rubber compound is stretched and molded under tension to compress the core. But rubber loses this elastic tension over time, a process accelerated by oxygen in the air. As the elasticity fades, so does the ball’s ability to spring back to its original shape after compressing on impact. You basically end up with a ball that no longer snaps back with as much vigor or speed.

The Felt Coating Absorbs Moisture

The outer layer of a tennis ball is made of a fuzzy, cloth-like felt. This textured felt helps provide grip for racquets to grab and spin the ball. But felt is absorbent and will soak up any available moisture from the air over time. As balls take on water, they get progressively heavier and lose their pressure. The soaked felt also changes the frictional forces on the ball during impact. This affects how the ball leaves the strings and alters bounce trajectory.

Frequency of Use Affects Durability

It’s not surprising that tennis balls lose pressure faster when they’re used more often. Each rally and serve puts stress on the ball as it compresses on impact against the strings, over and over. The forces involved end up breaking down the inner rubber core as well as degrading the exterior felt.

Professional tournaments actually use brand new balls for each match because the balls degrade noticeably after just a few games of hard play. Recreational players may not need new balls each time, but rotating multiple balls helps minimize wear and maximize freshness.

Manufacturers Design Balls to Lose Pressure

You might think tennis ball manufacturers would want to design a bouncy ball that lasts forever. But governing bodies actually specify that balls must lose their bounce and go flat after a certain point. The International Tennis Federation uses lab testing to regulate bounce standards and minimum durability. This is meant to ensure consistent ball performance across different playing conditions and temperatures. No one wants immortal bouncy balls, just predictable bounce over the usable life of a ball.

Canister Pressurization Slows the Process

When you buy new tennis balls, they usually come pressurized in a sealed canister. This helps suppress the pressure loss that would otherwise happen from normal air exposure. Pressurized cans maintain the bounce of new balls for longer compared to loose unpackaged balls.

 But even in pressurized cans, the clock is ticking as oxygen still permeates the packaging and rubber core over time. Proper inflation just buys you more usable life before balls go flat.

How to Extend the Life of Your Tennis Balls?

Let’s look at some practical steps you can take to keep your tennis balls in playable condition for longer before they go flat:

Store Them in a Cool, Dry Place

Heat and moisture are enemies of tennis ball pressure and bounce. When not in use, make sure your balls are stored in a climate-controlled room away from direct sun exposure. An airtight container like a bucket or large jar also minimizes air contact compared to a wire basket or mesh bag. The cooler and drier the storage, the better. Even the trunk of a hot car can accelerate pressure loss.

Limit Ball Compression During Play

We know hard impacts with the court compress balls and degrade bounce. Using ball baskets and catchers with a little padding or flex can help reduce some of that bounce impact compared to hard plastic or metal. Cushioned dampeners in the throat of ball machines also prolong ball life. Another tip is to rotate a set of 3-4 balls in and out of play rather than pounding the same ball over and over. This allows time for the rubber to recover between hits.

Re-Pressurize Them with an Inflator Tool

When balls start to lose their bounce, there are special ball inflator needles designed to pump them back up. These inexpensive tools pierce into the core to reinflate balls to the right pressure. A re-pressurized ball won’t be quite as lively as brand new, but can extend the usable lifespan for recreational play. It’s a cost-effective way to revive balls that still have decent felt and rubber but just lack the internal pressure.

Even with climate controlled storage, tennis balls attract dirt and debris that can grind away at the felt over time. Regular cleaning removes grease, grit and oxidation that cause extra friction and wear. Wipe down each ball with a tennis ball cleaner or soap and water to keep the felt fresh. The goal is to minimize any dirt buildup that could act like sandpaper on the ball’s surface. Keeping them clean preserves that soft felt coating.

Replace Balls Used for Competitive Play

For casual hits you can get away with balls losing some pressure. But most tennis organizations recommend switching out balls more frequently for competitive play. The United States Tennis Association says to change balls out at least every 90 minutes for optimal bounce speed and consistency. Or you may opt for new balls after each set. Either way, serious matches demand fresh balls to provide even playing conditions.

The Impact of Flat Balls on Your Tennis Game

You may be tempted to eke out every last hit from tennis balls, but how do flat balls actually affect your play? Understanding the performance drawbacks can help motivate you to keep your balls properly inflated.

Reduced Ball Speed and Bounce

The most obvious impact is the loss of ball speed and bounce that happens as pressure declines. Less compression inside the ball means less kinetic energy and slower shots. You have to swing much harder to get any power since flat balls don’t provide the same liveliness off the strings. The bounce gets lower and the ball loses its explosive energy.

Alters Bounce Height and Trajectory

Due to the loss of pressure, flat tennis balls won’t rebound off the court to their maximum height. Shots tend to bounce lower and skid rather than shooting up for easy preparation. This can throw off your timing while also reducing your margin for error since balls stay closer to the net. Mis-hits can sail long or bounce wider as well due to the flatter, more inconsistent trajectory.

Changes Tactics and Strategy

You have to alter your approach when balls lose their bounce. Big booming serves lose their potency. Touch shots like drop volleys are harder to control with flat balls. You have to swing harder and aim closer to lines to still penetrate through the court. Flat balls basically handicap players who rely on pace and accuracy. It rewards slower, high-bouncing moonball shots and other strategies.

Can Lead to Injuries and Arm Strain

The deadened hitting feel and off-center bounces require compensation that can strain muscles and joints. You grip tighter and swing harder to muscle flat shots with more force. The unusual impact stresses elbows, shoulders, and wrists from over-effort. Repeatedly overswinging starts to inflame tendons and ligaments. It’s just not a natural motion. Shin and knee injuries can also result from changed dynamics off low bounces.

Frustrates Players and Disrupts Rhythm

There’s no doubt flat balls disrupt the normal patterns and feel of rallying. The unpredictability of shot speeds and bounces makes it hard to establish any rhythm or consistency. You get tentative waiting on each weak bounce. Confidence takes a hit when you expect balls to react a certain way but they float and skip instead. It’s hard to be aggressive and play fluid, attacking tennis in those conditions.

When to Replace Old Tennis Balls

So when is it time to retire those fuzzy green veterans and get fresh balls in the rotation? Here are some signs it’s time for replacement:

  • For recreational play, every 2-4 weeks is a good rule of thumb.
  • For competitive play, use new balls for each match session or every 90-120 minutes of play.
  • Any ball that loses significant bounce and feels “dead” or flat.
  • When the felt coat is badly worn, balding, or scuffed.
  • If you notice cracks, cuts, or breaks through the felt into the core.

The regularity of replacement also depends on how frequently you play and the intensity. But remember you want to preserve quality practice just like matches. Don’t just save new balls for competitions and keep flogging those same dead balls for every drill. Get into the habit of grabbing some fresh cans on a regular basis so you always have good balls on hand.


How long do pressurized tennis balls last?

Pressurized balls in new cans will maintain better bounce for 4-6 weeks. After opening, balls lose pressure more quickly from air exposure.

Should you use old tennis balls?

Old balls with decent felt can be re-pressurized for recreational play. But competitive matches call for newer balls that haven’t lost bounce.

Why do my tennis balls crack?

 Tennis balls can crack from repeated hard impacts against the court over time. The felt also degrades with excessive dirt and friction.

How do you fix a flat tennis ball?

Special ball inflator needles can re-pressurize balls that have gone flat to restore some bounce. Storing balls in a cool, dry place also prolongs life.

Do colder tennis balls bounce higher?

Yes, colder balls bounce higher. Warm balls may lose some bounce, so keep new balls refrigerated before use.

When should tennis balls be replaced?

Recreational players can get 2-4 weeks of play. Competitive players often use new balls for each match.


Maintaining lively tennis balls ensures you get the most out of your equipment and play. Don’t settle for flat balls just to save a few bucks. By understanding what makes balls go flat and applying a few ball maintenance tips, you can enjoy much more consistent bounce and performance.

 Keep an eye out for pressure loss and rotate new balls into the mix before it starts impacting your strokes and strategy. Premium pressure produces premium play. Your legs and arm will thank you, not to mention your frustrated opponents. So show your tennis balls some love and keep them bouncing!