Instant Golf Swing


Golf Ball Compression from Low to High (vs. hardness)


by Robert Cotter (About the Author)
Professional Golf Ball Engineer
Director of Golf Swing Instruction, Instant Golf®

I receive a lot of questions about golf balls this time of year from golfers who are stocking up in preparation for a great 2019 season, or looking for the perfect gift for family/friends (or themselves)! The ball questions usually entail specifics about this or that product, ball comparisons, distance, specs, etc...

One such golfer recently wrote in looking for information on golf ball compressions as he likes a "softer" golf ball, but still wanted excellent distance.

In this report I thought I would explain the difference between Golf Ball Compression vs. Hardness as they are 2 important ball characteristics, and they are often confused.

If you have been playing this game for any period of time, you may remember the days when many golf balls came in both 90 and 100 compressions for a given model.

Typically, the 90 low compression golf balls were stamped with red numbers and the 100's with black. To the right is a 90 compression Titleist DT with a red number 3.

The 100 compression model would have had a black number. There is also a "side stamp" on both balls designating either 90 or 100 (compression).

Golf ball compression can be defined as the relative resistance of the ball to being deformed. It is also related to the firmness of the ball's core and COR (coefficient of restitution). This comparative value is determined with a finely tuned compression testing gauge similar to what is shown below.

It is important to note that the United States Golf Association (USGA) does not have a standard for golf ball compression. Hence, there is no minimum or maximum value a ball must exhibit to be considered legal. So it is important to note that:

Golf Ball Compression is a Relative Measurement!

Hence, one manufacturer may have a 95 compression golf ball (by their measurements) that is actually firmer than another company's 85 compression golf ball!

This is one of the reasons manufacturers seldom advertise or list their golf ball compressions these days. It also can give the consumer another data point with which they can rule out a buying one product or another. Typically they will use expressions like "low compression construction" vs. a number value.

Now, what about Golf Ball Hardness? Hardness is actually a property of the cover of the golf ball. There are specific standards for hardness and different measurement scales. Golf balls are measured using the "Shore D" scale.

Hardness gauges like the one on the right have a small metal point that is used to puncture just the cover of the golf ball (through the paint). A resultant cover hardness value may something like "60 Shore D" (not to be confused with 60 compression!).

These gauges are highly calibrated and often linked to computers for data transfer. These are very precise instruments and require a lot of data points (measurements) for a meaningful hardness value.

I have spent many hours measuring the compression and hardness of golf balls in the ball industry... it is eye opening.

Here's where the Compression vs. Hardness Story gets Real Interesting...

Some of the low compression balls out there actually have very hard covers! So they may feel soft off the driver or irons, but like "rocks" off the putter.

The driver and long irons/hybrids engage more of the core when a golfer strikes the ball, so the player is experiencing and sensing the properties of the core.

But with chipping and especially putting, the golfer feels the hardness of the cover (hence, less of the core) as the strike is a low velocity impact.

Some of those great low compression golf balls (2 piece - a cover and core) designed for the lower or moderate swing speeds actually have harder covers as a low compression/soft cover golf ball would typically be a formula for short drives and excessive spin (i.e. ballooning). No one would want that situation on the course.

On the other hand, the "Tour" balls the Pro's use (3 to 5 piece constructions) have very soft covers (urethane rubber vs. plastic) for that "drop and stop" action on the greens the top players require.

However, these Tour balls can also be quite firm (high compression). For instance the 2018 Titleist Pro V1x, a 4 Piece Tour ball has a compression of around 95-100 (rather high by today's standards), but a very soft cover for high spin on the approach shots.

The Tour pros have very high swing and ball speeds so a firm construction with a high COR core is one way to help optimize distance. The ball's other layers also help reduce side spin (hook, slice, etc...).

A ball like the Wilson Duo and its 29 compression construction (yes, not a misprint) with a soft plastic (not urethane rubber) has a different target audience and is optimized for golfers with different swing/ball speeds, launch angles, side spin issues.

It's a jungle out there with all those different constructions, cover materials, mantle layers, mind boggling dimple patterns, etc... and the well-intended golfer can easily get confused.

How I can help with your Golf Ball Selection...

As a US Patent Award winning golf ball engineer, I've worked knee deep in golf ball technology for years, developing new ball designs, and then matching the finished product to the correct recreational and professional golfers based on their personal needs and equipment parameters.

This experience led to an expert knowledge of ball components, how they affect overall ball performance, and most importantly, how to match the best golf ball to every type of players' game for more distance and accuracy.

That's why I added expert Golf Ball Recommendations to my new, 6 part golf instruction bundle. Golfers around the world have found this unique bonus a most beneficial addition to The Key To A Repeating Golf Swing instructional package.

Combining the correct golf ball for you with a reliable, Repeating Golf Swing is a winning formula for lower scores and more enjoyment from this great game.

If you are not happy with your game and are looking for a new direction going forward in 2019, I would like the opportunity to help you with your game by showing you The Key To A Repeating Golf Swing and my complete swing technique.

You will benefit from my firsthand experience inside the ropes, working with some of the top players in the game.

I am convinced you will benefit tremendously from my swing instruction, short game strategy, and professional golf ball recommendations (learn more below).

In all my years of playing golf, I have concluded that a golfer can not break 80 without a repeating golf swing. It does not have to be perfect, but it must be reproducible. When a repeating swing takes form, a whole new level of satisfaction results as the golfer is now able to play the game the way it was intended.

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Took my scores from the 110's to the 70's after struggling for years
with inconsistent ball striking and a stagnant handicap.

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Here's what you'll discover between the covers of the New 7th Edition:

checkmark  My Story - From the 100's to the 70's after a lengthy, bitter struggle with this great game.

checkmark  The comment from a Ryder Cup star (watching my swing) that reinforced my Swing Method.

 How to put your Golf Swing on Autopilot for every club in your bag.

 Why "traditional" instruction fails the determined golfer and my unique solution.

 The common denominator of all great men and women golfers - It's not what you think!

 The discovery on a PGA tournament practice range that changed my game forever.

 What you really need to know about alignment and grip pressure (this is critical).

 Exactly how to make your back swing consistent and Tour Caliber with every club.

 The role of Your Feet in the golf swing and how to use them correctly on every swing.

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 and much, much more Score Lowering insight and proven On Course Strategy.


Let me show you exactly how to deliver the club head right back through the ball at impact with tremendous power and control. Thousands of golfers, from beginners to scratch players, have put The Key to work in their games and the results have been astounding (over 250 testimonials on file).

In fact, the following is a note typical of the type that hit my inbox all week. It is genuine and unsolicited:


"First ever even par round"

"Hi Robert,

I just wanted to pass on that over the last few weeks I have being playing better and better, until the peak which was just yesterday.

I played at a local course and for the first time in my life I shot under 80, and not just under. I hit 38, 36. A day of firsts, first ever even par round, first time in the 70's, 4 birdies, just an all round amazing result.

I owe a fair bit of it to you as I am adhering strictly to your teaching.

Thanks again and best regards,

Dale N. - Maylasia

P.S. I have just received 2 dozen (name removed) golf balls, the ball you recommended for my game (although the score yesterday was with a (name removed), needless to say I'm starting to love this ball quite a lot) and the next time out I intend to try this ball. I'll check in with you early in the new year to see if there is anything else that you recommend.


"your instruction clears the head"


"I am sure you have received many testimonials in the past but how many within the first few hours.

I purchased & read your e-book this morning - as usual, after reading I needed to go to the practice range to see if it at least worked sometimes for me before committing any further time - patience is not one of my virtues.

Whilst I hit the ball well & hit what I was aiming at most of the time that is not the reason for this reply.

For the first time in my 40 years of golf I felt & knew at the top when I was in a good position to hit the ball solidly & could predict the outcome from the top of my swing.

In short, thank you - I now have the new sensation of the correct feeling at the top - golf is not a game of perfect but given 5 minutes practice I am convinced that "simple" is the answer for the amateur/social golfer to play good golf without hitting hundreds of balls per day. - your instruction clears the head of the thousand thoughts that ruin scores & a good day out with the boys.

I started a skeptic who expected the same rehash of information, instead I am pleasantly surprised."

Peter V. - Australia


Same day, dramatic improvement... Nice going Peter.

I get notes like these all the time. It doesn't matter whether you are trying to break 105 or 70, the rate of improvement is typically rapid once the "bad data" is stripped from a golfer, and The Key to a repeating golf swing can begin working its magic.

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I personally guarantee that if you make a sincere effort to apply the principles in "The Key To A Repeating Golf Swing" within the next 45 days, you'll realize lower scores and more enjoyment from your game.

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"Brilliant, stunning, unbelievable is all I can say."

"Dear Sir,

As you will by my e.mail address above I purchased your Key system and I am amazed by its immediate change it has had to my swing and went from 107 for an average round to 90. Brilliant, stunning, unbelievable is all I can say.

Thank you so much for your prompt reply and superb service you have given me, I have just read the ‘Key’ again, just to refresh and keep the practice going to improve even further.

..its great to be able to grin on the first tee knowing that I know what MY FRIENDS WOULD LOVE TO KNOW."

Martin S. - UK


"shot a 41! My best of the year"

"Talk about a testimonial... Your Readers would not believe this. Read your book Monday evening. Went to back yard to work on your tips. On Tuesday A.M. worked in my net on theory. Tuesday evening at league shot a 41! My best of the year (4 strokes off my average). All this within 24 hours.

Your a Genius!

Thanks so much."

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Author's Note: (this gentleman is 72 years young)


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"Hi Robert,

Thank you so much for your comprehensive response to my golf ball recommendation request. I am very impressed...

I read your wonderful e-book “The Key to a Repeating Golf Swing” this weekend, and found it to be the best golf book I have ever read (out of probably 40 or 50 of them).

Great job! And I’ll be recommending you to friends – although not the ones that I am currently playing for money!!"

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