Balls, balls and more squash balls

Squash balls: love them, wear them out, and leave them. Whether you like them or not, people question them, blame them and want to know more about them.  So here, for your reading pleasure is all you wanted to know about squash balls but were afraid to ask.

Oh and before you read on, we are NOT writing about either squash doubles, OR hardball squash and I’m definitely not writing about Racquetball. All of these use very different balls. The balls we’re covering in this blog are all the ones you use to play the international (standard) game of (softball) squash.  And in case you are short of time and just want to jump to the bit that interest you, here’s what we are covering:

• Which ball should you play with?
• Warming up the squash ball
• What are Squash balls made of, how are they manufactured, and who makes them?
• Pro: Double-Yellow-Dot Ball
• Pro White: Single-Yellow-Dot White Squash Ball
• Competition: SIngle-Yellow-Dot Ball
• Progress: Red-Dot Ball
• Intro: Blue-Dot Ball
• Pro High Altitude balls: Green & Orange Dot balls
• Summary

Which squash ball should you play with?

Squash is played with a soft, “dead” (meaning it doesn’t bounce much) ball. But before we go anywhere, let’s make sure everyone knows the following physics principles:

• Hot air expands. This means that the hotter the ball gets, the bouncier it will get as the air within it (which is sealed) will increase in pressure and thus become less soft which makes it bouncier.
• The higher the pressure inside the ball relative to the air pressure outside it, the higher it will bounce. This means that at high altitude, where the air pressure is lower, the relative pressure between the ball (which is sealed and has a fixed volume of air in it) and the surrounding air will be higher. It has the same effect as inflating a ball to a higher pressure level at sea level or just making it warmer (see first bullet point). This will cause the ball to bounce higher. This means that all squash balls are more bouncy at higher altitudes so people who live at high altitude (Denver, Mexico City, Calgary, etc) often play with the less bouncy Green Dot ball to compensate.

OK - now that we have all the necessary physics lessons under our belt, let’s move on to which ball should *you* play with.

Pretty much any squash player who has learned to serve and return will feel peer pressure to play with the pro (double-yellow-dot) ball. If you watch any two squash players play - regardless of level, there is a 90% chance that they are playing with the pro ball. This blog probably won’t persuade many (any?) of you to change this behavior. But if you are a B player (rating of 4.5) or lower you could absolutely benefit from playing with a single dot “competition” ball or an even bouncier one. Remember, the single-yellow-dot ball only has 10% more bounce so it’s a fairly subtle difference, and your rallies will start to look more like a pro. Only A players or better, generate sufficient power to make the pro ball bounce like it does when you watch a pro match. Don’t believe me? Try this for fun: go to YouTube, type in Squash Match and watch pro game. If you look closely at the players, when they hit a rail (a ball that stays straight down one side wall or the other), they will routinely hit the ball below the service line - then the first bounce will be at the back of the service box - then it will come off the back wall and the opposing player will hit it before the second bounce. If you are not able to match this feat *routinely* when you play - then you should move to a bouncier ball until you can make that happen. Here’s a little test you can try at your local facility:

Hit 10 backhand rails (backhand because generally this is the less powerful slide of the intermediate & beginner player), and keep moving to a bouncier ball until 7 of them look like this:

• The ball hits the front wall at the height of the service line (or close to it),
• It bounces only once before coming off the back wall.
• You are able to hit the ball before the 2nd bounce, after it has come off the back wall and repeat the process. 

You’ll discover that the ball has to really bounce off the back wall for you to have enough space and time to be able to make the shot again.  And for it to bounce it has to be really warm (hot). And for it to be really warm, you have to hit it surprisingly hard! I, your humble author, am a solid intermediate player (“B” or 4.2 rating) and I cannot do this drill unless I have a single dot ball. The only way I can make it with a double dot ball is to hit the ball way higher on the front wall (which is cheating).

The advantages of playing with a bouncier ball are:

• Easier to retrieve the ball = longer rallies
• Best way to improve your squash movement as you have time to move properly
• Improved fitness (because of the longer rallies)
• More fun! Because the points go on longer

The only disadvantage is that it is much harder to “hit the nick” - make the ball roll out of intersection of the floor and the wall - with a bouncier ball. But even with that there’s a silver lining: if you get so good you can hit the nick with a bouncier ball, you’re gonna kill it with the double-dot!

And just to remind you of the subtle differences between the balls, here they are listed in order of bounciness:

• Pro: Double-yellow-dot: 100% (baseline)
• Competition: Single-yellow-dot: 110%
• Progress: Red-dot: 120%
• Intro: Blue-dot: 140%

Don’t be bullied! Have the balls to make the right choice. 

Warming up the squash ball

You will notice that when two squash players get on court, they start by just hitting the ball to one another. This of course warms up the players, but in fact there are way better ways for a player to warm up for a squash match. What it really does is warm up the ball. (For why this is important, read the earlier section above.)  Over the years there have been plenty of machines that have been invented to warm up squash balls - my favorite being the machine they have at SCUBE (Squash Club of Upper Black Eddy) which is a hair-dryer with a little device bolted on the front to hold the ball. You turn it on, and 15 seconds later you have a warm ball! But all of these tricks are gimmicks because the ball will rapidly cool to the level that you can maintain it at your level of play. And it takes about the same amount of time for the ball to cool down as it does for you to heat it up to your level of play. So there really is no advantage to artificially heating up the ball. If you ever get a chance, pick up a ball right after a pro has been hitting it. You will find that it is really   H O T   !!  Pick one up after I’ve been hitting it? It’s decidedly warm. The double-yellow dot ball is designed to operate at 45 degrees celsius (113F for the non-metric inclined) once it has been warmed up. This is why different players should play with different balls. (See section above.)

What are Squash balls made of, how are they manufactured, and who makes them?

The Official manufacturer of squash balls is Dunlop. And from my experience they probably have a 75%+ market share. However, being the official manufacturer really just means paying for the privilege of being used at all of the pro squash events. There are plenty of other companies that make squash balls - maybe you can find a deal on one! At the bottom of this section, I’ll list them all.

Squash balls are between 39.5 and 40.5 mm in diameter and weigh 23 to 25 grams - so within a box of squash balls and certainly between manufacturers there will be some variation.. They are made with two pieces of rubber compound (Raw butyl rubber mixed with synthetics), glued together to form a hollow sphere and buffed to a matte finish. One of the things that happens to squash balls is that they get “shiny” which makes them slipperier and “faster” - which makes them harder to return. There are several little gizmos you can buy to “refresh” squash balls and make them if not new then at least much closer to their original spec. Here are some examples:

• Ballchemy
• Echo 2XP
• Etsy

Unlike ball warmers (see previous section - warming up the ball), these devices really will help bring a squash ball back to life. It won’t fix a “dead” ball, but it will fix one that’s become shiny and still has some life in it.

Here are links to all the manufacturers of squash balls that I could find, listed alphabetically:

• Ashaway (no link because although I could find Ashaway balls for sale, I couldn’t find them on their website which makes me think it’s just a branding deal)
• Black Knight
• Dunlop
• Head
• Karakal
• Prince
• Tecnifibre

Let me know if I missed one and I’ll update the list.

And finally, here are the documents put forward by the World Squash Federation that describe the official specifications for a squash ball:

• Specifications for Squash Balls
• Squash Ball Approval Programme

I will summarize them below.

Pro: Double-Yellow-Dot Ball

This is it. The king (or queen) of squash balls. It’s what all the pros use. And it’s the one that the vast majority of people play with. Even though most would be better off with a bouncier ball. Here are the specs:

Diameter: 40.0mm + or - 0.5mm

Weight: 24.0g + or - 1.0g

Stiffness @ 23°C:  3.2 N/mm + or - 0.4 N/mm

Seam Strength:  6.0 N/mm minimum

Note: the above regulations are applied to all squash balls, really the only difference between this one and the others is how high the ball bounces, which is called Rebound Resilience which means how high the ball will bounce when dropped from a fixed height. The bounce is measured as a percentage, so if a ball is dropped from 100 inches and bounces 12% it means that it bounced 12 inches. You can see from the stats below that even when the ball is REALLY hot it will only bounce about 30 inches (2ft 6in) when dropped from 100 inches (that’s 8ft 4in). And that’s the absolute best case scenario. It will only bounce 12 inches (or less) when dropped from the same height. And the colder the temperature the less it will bounce. Squash balls are “dead” meaning they are not very bouncy. And this is the least bouncy ball designed for use at sea level. (The Green Dot described at the bottom of this list has even less bounce because it’s designed to be played at altitude.) I remember playing on a court in NYC that had one poorly insulated outside wall (right side), and the other wall (left side) was inside the facility (NYSC Cobble hill if you must know - it’s gone now). In the winter, the right wall got super cold, and it made a big enough difference to the ball during play, that you could play a wicked kill boast of the right wall that would just die in the front as the ball lost temperature. 

The Double Yellow Dot ball Rebound Resilience - if the ball is dropped from 254 cm/100” is:

• @ 23°C. 12% (minimum)
• @ 45°C. 25% - 30%

Note:

@ 23°C = 73.4F - room temperature - it’ll bounce less if it’s colder.

@ 45°C = 113F - that’s HOT!

Pro White: Single-Yellow-Dot White Squash Ball

This ball is designed ONLY to be played on glass courts in pro tournaments. Play with it on your standard white court and it will be impossible to see. Both the glass court and the white ball were developed to make viewing the sport easier. It’s dramatically easier to see a white ball on a dark background on video than the reverse. (Go to YouTube and take a look if you don’t believe me). The specs behind the single yellow dot white ball and the double yellow dot black ball are essentially the same. Though the white ball is slightly bouncier. There has been some confusion around this because the white ball (I agree confusingly) has only one yellow dot - even though it performs more like the black ball that has two yellow dots not like the black ball that has a single yellow dot.. Don’t blame us, we didn’t make the rules, that’s just the way it is. 

I always think that the white ball looks bigger, but I’ve gone and measured them and it’s just an optical illusion. White objects look larger than black objects to humans because of how we process light in the eye. It’s called the irradiation illusion for those of you nerdy enough to want to learn more. It has nothing to do with the physical properties of the ball. 

It should be noted that glass courts play slower than regular courts (which is why the white ball is slightly bouncier than the black ball) so playing with a white single dot ball on a glass court at sea level is the toughest, most demanding game of squash you can play.

Competition: Single-Yellow-Dot Ball

This is a great ball to play with if you are an intermediate player or less. Or in the winter if your court gets a bit cold. It’s got about 10%  more bounce than the pro ball but otherwise is exactly the same.

Diameter, weight, stiffness & seam strength: all the same as the Pro Double-Yellow-Dot ball

Rebound Resilience - if the ball is dropped from 254 cm/100” how high will it bounce?

• @ 23°C. 15% (minimum)
• @ 45°C. 30% - 35%

Progress: Red-Dot Ball

Interestingly, there are no official rules around the size, weight, stiffness or seam strength of this ball. And the difference between it and the Single Yellow Dot is marginal. Personally, I don’t think the difference is worth it. If you want a bouncier ball I’d go straight to the Blue Dot (below) or stick to the Single Yellow Dot which at least as the standards setting body enforcing the rules behind it. The World Squash Federation simply says that the “improver” or “medium” ball should be coded with a red dot, and that it’s Rebound resilience @ 23 degrees C should be:

• @ 23°C. 15% (minimum)
• @ 45°C. 33% - 36%

Intro: Blue-Dot Ball

Like the red-dot ball, there are no official rules around the size, weight, stiffness or seam strength of the blue-dot ball. The World Squash Federation says that the “beginner” or “fast” ball should be coded with a blue dot, and that it’s Rebound resilience @ 23 degrees C should be:

• @ 23°C. 17% (minimum)
• @ 45°C. 36% - 38%

High Altitude balls: Green Dot balls

Because balls are bouncier at high altitudes (think Denver, Calgary, or Mexico City as examples - and read my physics explanation in the first paragraph of “Which squash ball should you play with?” above if you want to know why); there has been a special ball designed to compensate for this. It’s called the Green Dot. If you’re a mile high (or higher) then just take whichever ball you like to play with and go with the one that’s one stage slower! Here’s a guide:

I normally play with the:

• Double Yellow dot at sea level, so you should play with the Green Dot at altitude
• Single Yellow dot at sea level, so you should play with the Double Yellow dot at altitude
• Red dot at sea level, so you should play with the Single Yellow dot at altitude
• Blue dot at sea level, so you should play with the Red dot at altitude

Or just play with the ball you usually use and have longer rallies!  Here are the exact specifications of the Green Dot ball:

Diameter, weight, stiffness & seam strength: all the same as the Pro Double-Yellow-Dot ball.

Rebound Resilience - if the ball is dropped from 254 cm/100” how high will it bounce?

• @ 23°C. 9% (minimum)
• @ 45°C. 25% - 30%

Summary

Squash is fun. It’s so fun it can be addictive. And you won’t find a stronger, more welcoming, more supportive community than squash. When you play the game, longer rallies are more fun than shorter rallies. The best way to facilitate longer rallies is to get better at the game. But the easiest way to extend the rally is to play with a bouncier ball!

Just remember, don’t boast, just keep it deep. And if you can’t keep it deep, play with a bouncier ball.