At the Core of COR (Coefficient of Restitution)

The former land speed world record holder Bobby Thompson once said, “Too much speed is never enough.” For golfers this could translate as “too much distance is never enough.” Golfers are always attentive when it comes to driving the ball further. And so it was of no surprise that the design of “hot drivers” gets a lot of press coverage.

These drivers are deemed hot because of their “coefficient of restitution” (COR) numbers. Put simply this is a measure of the speed of a ball departing the club face relative to the speed of the club. When a club arrives at the ball at 100 mph and the ball leaves the club face at 83 mph, the club measures a COR of .83. The USGA has now raised the allowable COR to .86.

Before you rush out to lay down a few Ben Franklins on a new high COR driver, give a moment to consider the following:

  • If your driver swing speed is less than 100 mph and you have an .83 COR driver, moving to a .86 you gain three to five yards

  • If your driver is several years old its COR could be in the .76-.80 range. Stepping up to a .86 could mean 10 yards or more. Now we’re talking one less club for your second shot and a tighter landing pattern.

  • However, if you don’t hit the “hot spot” (that portion of the club face with the high COR) the gain will be less.

  • Driving the ball further demands better accuracy.       Adding ten yards to a drive that would have stopped five paces short of the rough now means a drive that carries the rough. If you don’t hit it straight, you definitely don’t want to hit it far.

Bottom Line: Higher COR can mean longer drives. Before you buy a high COR driver, buy some “impact tape” ($2). With a strip of it on your driver, you’ll be able to see how often you are hitting the ball with the center of the club face. Improve center contacts and all of your present clubs will send your shots further and straighter.


Enjoy the thrill of hitting better shots!

Heartland Golf Schools

St. Louis