What is COR in Golf? Coefficient of Restitution

Golf is a sport that combines a variety of skills, technologies, features, and scientific concepts to attain maximum performance on the course. COR is among the crucial factor that affects the performance of golf clubs. Therefore, it is necessary to understand and get a basic idea of what COR means and its relation to golf.

In this article, I will discuss the term Coefficient of Restitution (COR) in-depth, its measurement, its impact on performance, and how to test COR. Therefore, keep reading to gain insight. This term is technical and can be harder to understand, so let me explain it to you in simpler terms. First, let’s discuss its definition and purpose.

What is COR in Golf?

What is COR in Golf?
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COR is an acronym that stands for Coefficient of Restitution and is commonly used in the golf language. In mathematical or technical terms, the Coefficient of Restitution (COR) refers to the correlation between the final velocity and the starting velocity of the two objects after they bump or smash against each other.

In simple language, the Coefficient of Restitution (COR) refers to the transfer of energy between two bodies after collision. Additionally, in terms of golf, the Coefficient of Restitution (COR) refers to the transfer of energy between the club head and golf ball when they collide.

Furthermore, it is also referred to as the “trampoline effect” that is generated on the golf clubface during a collision. Let me give you with an example below:

The COR refers to the measurement of body A’s capacity to pass on energy to body B when they both collide. So in terms of the golf context, body A refers to the club face, and body B refers to the golf ball.

The Coefficient of Restitution (COR) impacts the amount of energy that is transferred from the clubface to the golf ball when the golfer strikes the ball. In addition, if the COR is higher, it means that less energy is dissipated during the collision. Or in another term, more energy is retained by the golf ball, which leads to a maximum distance.

Coefficient of Restitution (COR) Measurement

The Coefficient of Restitution (COR) is a figure or number that ranges from 0 to 1. These numbers are used to indicate how much energy is lost when two bodies come into contact together. The number 0 represents that all energy is lost. Whereas 1 implies that no energy is lost and all the energy has been transferred from the driver’s clubface to the golf ball.

Measuring COR on a Driver Head

However, achieving the ideal 1 number is extremely challenging because both the clubface and ball are constructed of distinct materials. This difference may result in losing a small amount of energy after the impact. Whenever the ball and clubface collide, there is always some energy lost, making it unlikely to achieve a COR value of 1.

How to Calculate COR Figure?

As said above, COR refers to the ratio of starting velocity to the final velocity, so to measure the COR of any object, you must keep this formula in mind. First, the golfer must strike the ball against the golf club’s face. Then next, measure the speed of the ball before and after it collides with the club face.

This will help you determine how much energy is transferred during the impact. However, this measurement process is really complicated. Therefore, a measurement called Characteristic Time (CT) was introduced to calculate the “spring-like” action of the golf club face.

Limits on Coefficient of Restitution

Many decades ago, there were no limits on the Coefficient of Restitution (COR). But in 1998, the United States Golf Association (USGA) implemented restrictions on the COR of every clubfaces. The USGA set the standard of 0.830 for every golf driver.

Therefore, if the limit exceeds the set standards, the club will be deemed non-conforming and will not be allowed in any official tournament. In addition, the golf club must not exceed the restriction and can not pass on more than 83% energy to the golf ball.

How Does COR Influence Golfer Performance?

What is the relation between the Coefficient of Restitution (COR) and overall performance? Let me explain it in simple words. The following are the influence:

Increased Distance

The higher the COR figure greater the distance and golf ball speed. The maximum distance allows the golfers to optimize their performance and achieve lower scores. The club with a higher COR figure implies that the ball will bounce back with greater speed and minimal energy loss, resulting in greater ball speed.

Final Thoughts about COR in Golf

COR stands for Coefficient of Restitution, which represents the ratio of the final speed to the starting velocity. In the context of golf, it refers to the transfer of energy when the driver’s face and golf ball collides together. Its main objective is to increase the distance and enhance overall performance.


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