Driver Clubhead Size and Performance – Who Wins?

Posted by on Apr 26, 2012 in Clubhead Design, Driver Fitting | 27 comments

I’m well aware there are a number of golfers who can’t stand looking down at drivers which to them, look so large in size they seem like a “grapefruit on the end of a stick.”  Golf equipment information forums will occasionally have threads in which golfer’s plea for the companies to develop and introduce sub 400cc drivers. Within such comments invariably is the question, “can a smaller size driver perform as well as a larger one, and if so, why haven’t the golf companies offered at least an alternative smaller size driver?”

In a nutshell, if they can be sure it will sell enough to far exceed the cost of development and marketing, you can be absolutely sure the golf companies will make it. They’re all in the business of making money. That’s why if you don’t see any smaller size drivers being offered, the companies are sure the demand is just not going to be significant enough to merit the introduction of a smaller size driver. Period.

Way too many golfers still believe that “bigger is better” when it comes to driver head performance to allow companies to spend the money to develop a smaller size model.

From a pure performance standpoint, the larger the size of a clubhead, the higher its Moment of Inertia could be. In turn that means the larger the head, the better it’s off center hit performance could be. Likewise, the larger the size of the head, the larger the face area could be. Larger size face does not mean a higher COR for more distance because we all know it is eminently possible to reach the USGA’s limit on spring face capability on a face that would be commensurate with a sub 400cc size driver head. But a larger size face can make it easier to design a variable thickness face that could offer a very high level of off center hit performance.

Bottom line though is that it very definitely is possible to make a driver head with a volume of 380cc to 400cc that would perform every bit as well for distance and off center hit performance as any of the 460cc heads currently on the market. Yes, the 460cc head’s MOI would likely be higher, but not by so much that it could bring about a noticeable improvement in off center hit performance. MOI modeling studies for TWGT have shown that a difference of 1400 g/cm2 in the MOI of a driver head, basically the difference between a 360cc and 460cc volume head, offers only a difference of ¼ of 1 degree in resistance to off center hit head twisting. And that’s for a golfer with a 109mph clubhead speed. For golfers with a 100mph and lower swing, the additional off center hit improvement from a 1400 g/cm2 difference in MOI is even less.

Hence if all the golf companies could be convinced enough golfers would buy the smaller size driver to make it worth the expense to develop and introduce it, golfers would not skip a beat in terms of the performance they could achieve with a smaller size head. It’s all a matter of supply and demand – and right now there is just not enough demand to generate a supply.

27 Comments

  1. Me. Miura says that the miura baby blade is easy to hit .
    The theory goes , it’s easier to find the sweet spot . And it has more mass . I agree a cavity back offers more forgiveness, but there is less mass behind the sweetspot , so maybe a muscle cavity would be best way to go ?
    As for big headed drivers , personally found more clubhead speed and directional forgiveness using a 12 degree two wood .
    A side note , thank you Mr. Wishon for all your contributions to this wonderful game and thank you for taking the time to respond to your many fans .

    • PAOLO

      I hate to disagree with the ‘God like” status that some golfers like to award to Mr Miura but that statement about a blade being easier to find the sweet spot because it has more mass behind the sweet spot is absolutely false and a marketing myth. An iron head only needs to have a face thickness of 4mm on the heads with less than 30* of loft made from carbon steel and 3.5mm on heads made from 431 or 17-4 stainless steel to feel completely solid and to have the face be completely rigid for impact with a golf ball. I know this because I have designed more than 200 different sets of irons in my career. If you make a cavity back iron of lower loft with only a 3mm thick face section, higher speed players will begin to feel some face vibration that to some players can detract from a solid feel of impact. But for the normal strengths of steel alloys used to make iron heads when the face section is 4 to 3.5mm it is plenty rigid enough to prevent any change of feel from an on center hit.

      The ability to find the sweet spot on an iron is controlled by how well the length, the shaft weight, the total weight, the swingweight and the grip size fit each individual golfer’s strength and swing tempo and backswing to downswing timing so the golfer can achieve his highest level of swing repeatability, and from that, to then achieve the highest level of on center hit consistency. It has nothing to do with the design of the head itself.

      TOM

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  3. Hi Tom,

    I have noticed if I balance the club on my finger at the balance point of the shaft the toe of all my clubs will spin clockwise until the toe points straight down. If I then try to use the forefinger and thumb of my free hand to rotate the shaft to point the toe back towards the sky it is extremely difficult near the balance point of the shaft but relatively easy using the grip end.

    So I decided to advance the head about 30 degrees closed while perpendicular to my body. The club is in my lead left hand and I maintain a neutral grip. I can feel the force of gravity wanting to close the club face so it can point toe down. To square the face at address I use the last 3 fingers of my left hand and this points the lead hand V towards the trail shoulder. I prefer a reverse overlap grip with all the fingers of the trail hand on the shaft and the lead hand index finger overlaps the pinky of the trail hand. Using the last 3 fingers of my lead hand to square the club face creates tension in my lead forearm however I can feel the club head mass wanting to release that tension so I keep it as the feel I need to know if the head is releasing correctly. Since the club head must rotate counter clockwise for a right handed player to freely release the clubhead to the force of gravity and centrifugal force I cannot find a better way to take advantage of the club heads desire to rotate toe down. I have found that if I place the club square then take my grip the club heads mass trys to rotate clockwise during my downswing. To fight the clockwise rotation requires counter clockwise rotation of the club face to start the backswing yet without any tension in my lead forearm I don’t know where the club head is at transition or through impact. It is more Russian-roulette. I am very keen on club design from an engineering perspective and how it is supposed to work. The lead forearm tension seems to be the only way I can actually feel the club head trying to force its mass counter clockwise verses me trying to force the club face shut.

    There is a term I learned from Mike Austin called Lead Angle. No one teaches it and he never explained it. When I search lead of a golf club it always returns as forward shaft lean. For a screw lead is described as:

    Lead is the “axial advance” of a helix or screw during one complete turn (360°) The lead for a screw thread is the axial travel for a single revolution.

    I was hoping you could shed some light on using the club heads own mass to freely release the tension in the lead forearm so that it is not a conscious action like I wrote about or counter thinking to the clubs design and proper use of the tool?

    Lastly there is only one golf teacher that teaches the lead forearm tension as critical to using the club correctly (Darrel Klassen) the problem however is he doesn’t explain it other than to say the pros all start with a shut face and than use the last 3 fingers of the lead hand to square the blade so it looks square to the target at address. He goes on to say that most amateurs will feel the tension in the lead forearm and say, ” oh I don’t like that feeling and eliminate it before the backswing” that hinders the free natural release before the swing even begins.

    Your thoughts and experience are greatly appreciated!

    • ALAN

      After a total of 43 yrs with golf clubs, the last 31 yrs of which I have been a clubhead designer and the past 26 yrs spent in detailed clubfitting analysis and research, at this point in my career I feel that I have come to a point where I believe it is far more important to focus on the things about equipment that we know for sure do matter for which golfer swing types, and to forget about splitting the hairs too thin on matters that don’t have as much chance of making a real difference.

      I feel after all my work that the keys to delivering the clubhead more consistently to the ball rely on the golfer being as well fit to the length, the total weight, the swingweight/head weight and very much so the grip size. Spend the time through experimentation hitting shots with different weight combinations (possibly with the help of a clubfitter) to find the very best combination of those 4 things and you will find you will achieve the best shot consistency and swing consistency that is possible for your neuro-muscular makeup.

      I too am big on reducing tension in the arms but I have found the best way to do that is first to find the most comfortable grip size for the golfer, then to find the best combination of length + total weight + swingweight that best matches the golfer’s strength + swing tempo + swing timing.

      Clubheads shall forever be made so the shaft has to be inserted on the heel end of the head because that is a requirement in the rules of golf. You cannot make a driver/wood/iron with the shaft inserted in the center area of the head. So as long as the rules compel all heads to be made so all the mass is out there in front of the shaft, you will always notice things like you state about rotating the head and experiencing some resistance. Thus you can’t mess around with any types of odd techniques to overcome this because heel shafted heads are what we have to play with. Hence within those factors, finding the very best combination of length + total weight + swingweight + grip size is how you achieve the most swing repeatability and shot consistency that you and your neuro-muscular makeup are capable of.

      TOM

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