MOI question.

[Cloran]

I had a discussion with a guy from work that perhaps you gents can help out with. I believe the USGA tests MOI by using just the club head, correct? Therefor, the actual MOI a player will see during the course of play will be less (perhaps much less) because of the shaft length, flex, etc. That's how I understand it... my friend at work said no, 5900 is 5900.

[thewitt]

The USGA only tests the clubhead - correct.

 

The limit on MOI for a clubhead is simply a number.

 

Whether or not 5000 will result in a better head for you than 4500 is going to depend on much more than just those 500 gm cm sq

 

Arguably the difference in 1000 gm cm sq between a high MOI head and a lower MOI head will result in a 1 degree difference in directional control from off-center hits. Most of us cannot hit the ball consistently enough swing to swing to notice this.

 

The real reason that high MOI heads seem to be having a positive impact on control is they achieve this higher MOI by having a shape that also results in a CG much farther back from the CG of the shaft - resulting in a higher effective loft at impact, more back spin, and a straighter shot as a result of less side spin.

 

-t

[Golfer-X]

"THAT'S THE FACT JACK" :russian_roulette:

[thewitt]

I'm just reporting what we're seeing in the real world now that we have a dozen different driver design in play with "High MOI" numbers.

 

The launch monitor numbers show higher launch angle and backspin numbers in virtually all designs for measured lofts - which all clubmakers know result in straighter shots...

 

The math can be be done to calculate the differnece in MOI at impact and the resulting face angle changes. I believe Wishon posted these numbers already based on his engineer doing the math.

 

-t