Frank Thomas is a former technical director of the United States Golf Association. He has written several books about golf equipment, the most recent being 'Just Hit It: Our Equipment and Our Game.'
If you have a question about golf equipment, e-mail him at firstname.lastname@example.org.
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?
Yes, the Coefficient of Restitution (COR) will eventually decrease as you continually hit the center of the face. (For more on COR, click here.) But this should not be of too much concern to most of us because we do not swing fast enough and don't hit the sweet spot very often. Although they are very thin, today's club faces will take about 5,000 to 10,000 impacts on the sweet spot at 115- to 120-mph clubhead speed before the face starts deteriorating. Most drivers will be obsolete or worn out in other ways before they hit that many pure tee shots.
If you are concerned about your driver, place the edge of a credit card on the face. It should rock because of the "roll" and "bulge" that are built into new clubfaces. If the card does not rock, and you cannot see light under the edges, the face has flattened, and you should think about getting a new driver.
For more from Frank Thomas, go to franklygolf.com.