What Is The C.O.R. For A Golf Club

When two objects collide, the transferral of energy is expressed as a measurement of energy retention or loss, with 0.000 being the loss of all energy and 1.000 being perfect transfer of energy from one object to another.

There are some reasons that a golf club and golf ball can not result in a perfect elastic collision with the COR being equal to 1:

a. Club faces and balls are manufactured from completely different materials.

b. Club faces and balls weigh much differently.

An example of a collision where the energy transfer is very high is in the game of pool. A cue ball transfers almost all its energy to the object ball, causing it to speed off at almost the same speed as the cue ball before it struck the object ball, while the cue almost stops. In this case the balls are of the same material and weight.

Here is an example that will give an idea of the increased distance obtainable with increased COR: A driver with a face COR of 0.830 will hit a ball 4.2 yards farther than a driver with a face COR of 0.820, assuming a 100 mph swing speed.

The United States Golf Association has limited the COR for golf clubs to 0.830. It doesn’t mean much to the average slow swinging golfer, now that almost all legal drivers are manufactured to be at the 0.830 COR level. It is, however, a distinct advantage for the golfer with the faster swing speed because the high COR produces better for him.

COR limitations affect only drivers, as most are made from very thin and springy titanium. Most club outlets publish the COR for the drivers that they sell. If your unsure that the driver you like is legal, consult the USGA website for a list of non-conforming drivers.