QA Square Drivers Spin Control

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Editor's Note: This is the latest in a weekly Q&A feature from The Golf Channel's Chief Technical Advisor Frank Thomas. To submit a question for possible use in this column, email letsbefrank@franklygolf.com
 
Nike and Callaway are introducing new square headed drivers for 2007. They claim the square head shape has allowed them to increase the MOI and thus produce a straighter hitting driver. I understand the MOI theory, but does a square head really make a difference or is this just more marketing hype? -- Richard
 
Richard,
Let me say the following: When the MOI increased from 2,000 gm cm to 4,000 gm cm there was a significant improvement in performance on mishits. But from 4,000 gm cm to 6,000 gm cm there is very little. Most of the bigger 400cc to 460 cc drivers have about 3,500 gm cm to 4,000 gm cm MOI and perform very well.
 
The latest square drivers have improved the MOI to 5,300 gm cm but the improvement in performance doesnt come close to the improvement we have seen from 2,000 to 4,000 gm cm. A good case of diminishing returns.
 
The other reason why the manufacturers are doing this is to be different and also to approach the MOI limit placed by the USGA. Any time there is a limit golfers assume that being just under it is good. Thus the reason for the 460cc drivers (limit is 470cc) and now the high MOI. I very much doubt that you will be able to see any real measurable difference in performance because of the increase to 5,300 gm cm unless you really miss the sweet-spot.
 
There is not much more room for movement in performance in drivers so pushing the envelope re. the limits seems to be a good way to impress golfers. I believe that in time we will see a return to 400 cc drivers and traditional shapes.
 
Frankly, for the moment, being square is cool.
 
For more on square drivers check out my latest newsletter by clicking here.
 
Dear Frank: Do the current drivers (large head - thin face) get 'weak' after use? That is, does the COR decrease over time with a consequent loss of distance?
Sincerely
--Stew

 
Stew,
Yes the COR will eventually decrease as you continually hit the center of the face. The time it takes depends on the speed at which you impact the ball and how often. The club faces are very thin and it will take about 5,000 to 10,000 impacts on the sweet spot at 115 to 120 mph head speed for the face to start deteriorating. This number depends on the manufacturing process and control of the face thickness and how it is welded to the body of the head.
 
This should not be of too much concern to most of us because we do not swing fast enough and dont hit the sweet spot very often. By the time we get to the critical number we will probably need a new driver anyway.
 
The best way to check if the face is starting to deteriorate is to place a credit card edge on to the face and check to see that it is rocking on the face because of the roll and bulge built into the new club face.
 
If the card does not rock and you are unable to see light under the edge, the face has flattened and you should think about getting a new driver.
 
Frank,
I am a 20-handicapper. I use a 10.5 driver, and the lowest spin rate I have ever been able to achieve is 4,000. Should I use a more lofted driver?
--Lou

 
Lou,
I dont know what your swing speed is, but if its 80 to 90 mph then your launch angle should be 13 to 14 degrees and spin rate should be about 3,500 rpm. If your launch angle is higher than this, get a driver with a lower loft; if not, then stay with what you have. Four thousand rpm is not bad. The other thing you can try is to hit the ball a little higher on the face to decrease the spin, but this will increase the launch angle.
Hope this helps,
Frank
 
Click to purchase the Frog PutterFrank Thomas, inventor of the graphite shaft, is founder of Frankly Golf, a company dedicated to Helping Golfers. Frank is Chief Technical Advisor to The Golf Channel and Golf Digest. He served as Technical Director of the USGA for 26 years and directed the development of the GHIN System and introduced the Stimpmeter to the world of golf. To email a question for possible use in an upcoming Let's Be Frank column, please email letsbefrank@franklygolf.com