Why do new multi layer balls used on tour spin less than the old tour balls off the driver but spin the same as the old wound balls off the wedge? Ryan Dees, Gainesville, Fla.

During the collision between the driver and the ball (which lasts for less than half a millisecond, 200 times faster than you can blink your eye), there's an average force of 1,500 pounds being applied to the ball. This violent collision compresses the ball to about two-thirds of its diameter. The cover thickness is less than 3 percent of the size of the ball but doesn't much influence the outcome of this collision.

Two-piece balls, which have been on the market for many years, will spin less and go a little farther off the driver than the soft, wound balata balls that were used on tour until five years ago. The hard-core two-piece ball will spin about the same as the wound ball off the wedge only if it has an extremely soft and relatively thick cover. But such a cover reduces the ball's distance off the driver. The trick is to get a ball to spin less than a wound ball off the driver but the same as a wound ball off the wedge. A multi layer ball will do this because it has a soft core (for speed off the driver face) surrounded by a hard mantle and a thin soft cover. The mantle reduces spin off the driver, and the cover, too thin to influence driver launch conditions, is soft enough to significantly influence the spin off the wedge. The collision between the wedge and the soft cover, less violent and more oblique than with a driver, generates more spin. Thus, designers combined new materials with a better understanding of the synergy between ball and club to create a more efficient multi layer ball.

Could you please shed some light on how to determine the proper driver length and what the average driver length is on tour? Chuck Mooney, Davenport, Iowa.

The average length driver on the PGA Tour is 44 12 inches. For most golfers, I recommend no longer than 44 inches. This will give you more control than the longer driver. You will develop more confidence and make a better swing. On average this will give you more accurate and longer drives. You might not win bragging rights with an occasional testosterone-inspired long drive, but you will lose fewer balls and enjoy your game a lot more. Shaft length is important, but don't forget to make sure you're comfortable with the flex of the shaft. Remember: If you think the 44-inch driver is too short, how on earth are you going to use a 3-wood or your hybrids, which are a lot shorter?

Is there a published report that gives a true count of equipment used by PGA Tour pros? B.C., New Orleans

An organization called the Darrell Survey goes through every competitor's bag on Thursday of every tournament to verify the pros are using the equipment they claim to be using or the manufacturers claim they're using. It has conducted these surveys for about 60 years. The information is sold to the manufacturers, who use the counts for advertising purposes. The information is considered reliable--at least for the first day of the tournament. Players may change equipment after the tournament begins, potentially draining the winning putt with a club not reported on the survey.