Cor Doesnt Matter Understand The Core Reasons Why
Posted by Goody on 04/12/08 in Recreation and Sports
C.O.R. or Coefficient of Restitution is the scientific name for this oft used term but rarely understood measurement that effects the ability of your driver to garner you the most distance possible off of the tee box.
But what the ‘heck’ is it, what does it mean and is it important.
Well in a single word as to how important is it “NOT” WHY ? I will tell you but first a little bit of history
Back in the early 1990’s golf club manufacturers began changing the design of irons to have perimeter weighting following the trend that Karsten Solheim used on his famous Anser putter. Realizing the greater sweet spot that the perimeter weighting produced, golf manufacturers began designing irons that had a greater sweet spot that increased the amount of club face contact with the ball and a reduction in twisting that contributed to straighter shots. In order to do this they not only had to change the distribution of the weight but also INCREASE the size of the actual iron itself.
The challenge was to make the club head larger without violating the USGA restriction on the weight of the club. Understanding this, the quest for ‘exotic’ material began and their use in the majority of the clubs we use today.
It wasn’t long before the use of these materials found their way into the “EGO” club, the driver, the one club that everyone wanted to hit long and straight but were never able to. Thanks to Roland Reagan and the end of the cold war, not only was titanium the metal of choice but with the reduction in the defense contract industry you now had an abundance of engineering expertise to help understand the tricky properties of this metal.
This change in the physical design and appearance of the club went from a 150cc club to today ones that are up to 460cc in size. WOW!!!!
In addition to the club head being larger and lighter (some 40%) it now allowed club manufacturers to increase the length of the shaft and the overall length from 43″ to 45″ and beyond. This combination of a lighter LARGER head and a longer shaft resulted in providing additional power and velocity that in turn increased the distance that you could drive a golf ball.
The accuracy issue is one I will cover in another article but in the words of CBS commentator Gary McCord “With the old drivers my playing buddies use to just hit the ball mediocre and into the rough, NOW with these new exotic drivers they hit it longer and instead of the rough, they are in the WOODS”
But all that said why doesn’t it matter to me when the sales guy at my local golf shop tells me that this club has the HIGHEST C.O.R. allowable on a driver?
Because though all of the testing, retesting and technology increases with this thing called C.O.R. , ALL golf club manufacturers have reached the HIGHEST ALLOWABLE limit that is set by the USGA and soon the R&A. And in the now and distant future these governing bodies will NOT change that limit and increase it in any way PERIOD. Why, because of the incredible distances that professionals are hitting the ball. Once again I will address the REAL reason why they are hitting the ball further and it Ain’t all about C.O.R.
So next time you go plop down $500 smackers for that new Ubertanium driver remember that no matter what metal they are using it ain’t going any further than the other drivers on the rack.
For those of you that would like a simple explanation of C.O.R. here it is.
The maximum allowable limit now is .830 C.O.R. which is a measure of energy that is transferred from the clubface to the ball. It is called the elastic property of the club face and its ability to ‘flex’ inward and then rebound or ’spring’ forward transferring that energy into the golf ball. Perfect elasticity would be 1.0 or a 1-to-1 transfer of ALL of the energy of the golf club face into the ball. That from a scientific point is impossible.
For example if you drop a tennis ball down onto the court from a distance of 10′ and the ball ‘rebounds’ to 8.3′ the court has a C.O.R. of .830, simply huh. Not all of the energy is transferred to the ball but the majority of it is. In tennis I would be surprised if the court would give as much as 5′ of rebound. Try it and let me now how far it bounces.
So now I hope this explanation of C.O.R. and its benefits to your golf game are explained. It was beneficial in the early days but now that ALL clubs are manufactured to that high level it doesn’t matter which club you get.
What can I do to get more distance and straighter tee shots ? Stay tuned and we will cover that in another article. Unbiased and based entirely on fact and science.
Ed Weatherby is a lifetime golfer, professional club architect and the founder of The DaVinci Golf Academy in Europe.
You can contact me at edweatherby@davincigolf.com or visit the website at http://www.davincigolf.com
Tags: cor, custom fit, driver, face, golf, hot spot, metal, physics, science, wood
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