The U.S. Golf Association announced to equipment manufacturers Wednesday that it will place a higher limit on clubhead moment of inertia (in essence, a clubhead's resistance to twisting on off-center hits) than what it had previously proposed. The ruling goes into effect May 1, and applies only to "woods," in particular drivers.
The original proposal, which was announced August 30, 2005 suggested that the limit would be 4,750 grams-centimeters squared. The proposal sought out input from manufacturers during a notice and comment period before the rule would be implemented. An e-mail to manufacturers Wednesday morning, obtained by Golf Digest, stated that the limit will be 5,900 with a tolerance of 100.
According to the USGA notification letter, the increase was the result of "careful consideration of the comments received from equipment manufacturers" during the notice and comment period.
"At the top level, there's not any appreciable difference [in performance]," said Dick Rugge, USGA Senior Technical Director. "It really doesn't mean anything. If you were talking about going from 2000 to 3000, then yes, but not at this level. We thought this was an appropriate place for us to set a limit to protect the game from any future unknown developments."
Mike Stachura is a senior editor for Golf Digest magazine