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What Makes A Golf Club Illegal?

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In the great game of golf, details are often what separates the winner of a tournament from the runner-ups. All around the world, professional golfers are trying to get every advantage possible over their opponents in order to increase their chances of winning.

However, it is possible to go overboard and use illegal methods to increase golfing performance. Those illegal methods including illegal golf clubs. Therefore, since illegal golf clubs are a rarely discussed topic, you may wonder: what makes a golf club illegal?

In this article, we will tell you exactly some of the elements that make a golf club illegal.

What Makes A Golf Club Illegal?

A golf club will be deemed illegal if it does not conform to USGA and R&A regulations. Illegal golf clubs have non-conform dimensions, volumes, shapes, coefficients of restitution, and more. Examples of illegal golf club include clubs longer than 48 inches, clubs with molded grips, a sanded club face, and more.

An illegal golf club is a golf club that does not respect the regulations created by the USGA & the R&A.

Down below are rulings concerning the different parts of the golf club in order to make it legal.

Golf Club Shaft

A regulated golf club characteristic is the geometry of the golf club. For starters, the length of the golf club shaft needs to be between 18 inches and 48 inches. This rule does not apply to putters.

The golf club shaft needs to be relatively straight along its length. If the shaft is too bent or not straight enough, it will be an illegal golf club.

A highly regulated element of golf clubs is called the Coefficient of Restitution (abbreviated COR). The coefficient of restitution determines how effective the golf club shaft is at transferring the energy stored in it when it bends back to the ball.

A higher coefficient of restitution means that the golf club will be more effective at transferring energy back to the golf ball. For example, a golf club with a COR = 0.75 will be more performant than a club with a COR = 0.60. The coefficient of restitution needs to remain within acceptable ranges to be deemed legal.

Golf Grips

When it comes to the golf grip, it needs to be straight and fixed to the shaft. It cannot incorporate any ridges or be molded in order to better fit hands or fingers.

The grip for all clubs except the putter must be circular in cross-section, except for the possibility of a straight, continuous, slightly raised rib along the full length of the grip, or a slightly indented spiral.

The putter’s grip can be noncircular in cross section, as long as the cross section has no concavity, is symmetrical, and stays relatively similar throughout the length of the grip.

For all clubs, the grip can be a bit tapered, but it should not have any bulges (marked convexity) or waists (significant concavity). The cross section of the grip, measured in any direction, cannot be larger than 1.75 inches.

For clubs other than the putter, the grip axis must coincide with the golf club’s shaft axis.

A putter golf club can have two grips installed if they are both circular in cross section and their axes coincide with the golf club shaft’s axis.

Golf Club Head

In general, the club head needs to have a plain shape, rigid, and all parts needs to be functional in nature, not decorative. A golf club head cannot have holes through the face, through the head, features only existing to meet dimensional requirements.

A golf club head also cannot have features extending in or out of the club head face, nor features that extend a lot above the top of the head. A golf club head also cannot have electronic or optical devices installed onto it.

An example of an illegal golf club is a golf club that has many little studs on the club face instead of grooves. These many tiny studs gave the golf ball an incredible amount of spin, giving players an unfair advantage in some situations.

An other element of a golf club that would make it illegal is if the golf club head has a volume that goes outside of the acceptable range. For example, a driver club head cannot be larger than 460 cubic centimeters.

If a driver club head is larger than 460 cubic centimeters, in order to gain more carry distance, it will be deemed illegal. Getting caught with one of these golf clubs in a professional setting will lead to penalties.

The golf club head needs to fit in a 5” x 5” x 5” box.

The sole to crown height of a golf club cannot exceed 2.8 inches, and the heel-to-toe length must be longer than the face-to-back distance. Without this, you would have an odd looking golf club that would not look much like a golf club anymore.

The angle between the golf club shaft and a vertical line coming out of the club head must be 10 or more degrees. The angle between the shaft and the club head, viewed from the toe of the head, must not be more than 10 degrees behind the club head nor more than 20 degrees in front of the club head.

The bottom of the golf club’s heel should be contained within a radius of 0.625 inches around the shaft’s center. This rule does not apply to putters.

The club head needs to be attached to the shaft in a specific way for the golf club to be legal for tournament use. The shaft needs to be attached to the heel of the club head through either a socket or single plain neck. This rule does not apply to putters, as the shaft can be attached anywhere to the head.

When it comes to Woods and Irons specifically, you cannot have cavities in the outline of the heel or toe of the club head that can be viewed from above. You also cannot have significant or multiple cavities in the outline of the back of the club head that can be viewed from above.

Still for Woods and Irons, you cannot have transparent material in the club head to make a non-conform feature become conform. You also cannot have features that extend beyond the outlines of the club head when viewed from above.

General Rules

Another thing to note is that if your golf club breaks during play, you can still use it. Furthermore, playing with more than 14 golf clubs in your bag is also illegal, and will get you severe score penalties if you are caught during a tournament.

On the other hand, if you purposely modify the characteristics of your golf club, be it by damaging it, making adjustments to the loft, and more, then you are no longer allowed to use that club for the remainder of the round.

Changing settings on your clubs is like having more than 14 golf clubs in your bag. However, if you change the setting back to its original configuration as quickly as possible, you can use the club again without penalty.

It is also illegal to use a golf club on which you apply a substance to modify how it performs when hitting the golf ball. You can still clean your club though.

For even more information and additional rulings about golf club legality, you can read the USGA’s equipment conformity guidelines here.


There you go! After reading this article, you have discovered exactly some of the elements that can make a golf club illegal. If you are caught playing in a sanctioned and serious golf tournament using one of these clubs, you can expect some large penalties!

Would you ever risk using an illegal golf club? Have you before? Let us know in the comments down below!

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