USGA rules stipulate that the clubhead shall not exceed a volume of 460cc. This should make one wonder, why are larger driver heads so advantageous? Research shows that the modern (2007) driver, when hit off center will create 14 yards more distance than a driver circa 1995 hit on center!* While we may not hit all of our drivers perfectly, it is good to know that our equipment will reward us as much as the rules allow.

If you have ever wondered why the increase in size makes such a difference, the explanation is not very difficult to follow. When you increase the size of the head of a golf club, generally there is also an increase in the head's MOI, or Moment Of Inertia. A higher MOI allows the club to remain stable even on severely off-center hits. Since the clubhead remains more stable, more energy is released into the ball, instead of into twisting the clubhead. This creates longer, straighter shots.

Larger objects are simply more resistant to twisting. The difference between hitting an off-center shot on a small head compared to an off-center hit on a large head is very comparable to the difference between the amount of energy it takes to rotate a wheel with a smaller diameter compared to the energy it takes to rotate a wheel with a larger diameter. It takes a lot more force to spin the larger wheel - we might as well say the larger wheel is more "resistant to twisting" than the smaller. The same physics applies to your golf clubs.

Let us not forget that the driver is not the only club in your bag where a higher MOI is important. While the same case can be made for fairway woods and irons, a higher MOI can help you with perhaps the most important club in your bag - your putter! Old blade and heel-toe style putters have a very low MOI. This means that a putt struck even slightly off-center will twist the clubhead and cause your putt to miss left or right. Having a putter with a higher MOI (Mallet and modern styles) will noticeably increase your margin for error on the putting green. So why not give high MOI a try?

*Source: Golf Digest, 06/07.