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tww

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tww last won the day on November 27 2014

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  1. At best, a draw bias driver head can only tweak the ball flight shape a little bit, and only when 1) the amount of weight moved into the heel is north of 25 grams, and 2) the golfer is very consistent with his path and face delivery and point of impact on the face. They are NOT a slice corrector at all - that is the domain of the face angle and having a slicer use a driver with a face angle that is more closed than what he had previously. Research on face angle shows that it can act as a degree for degree reduction in the amount of slice or hook that a golfer may have from his path and face delivery upon release. At a carry distance of 200 yds a 1* change in the face angle will reduce the curving misdirection of the slice or hook by around 4 yards. At a carry distance of 250 yds a 1* change in the face angle is worth 5.5 yds of correction. Draw or fade bias cannot do that and here's why. Let's talk draw bias for this explanation. As you put more weight on the heel side of the head, you pull the center of gravity toward that weight, and off the center of the face. So when you hit the ball on the center of the face, impact then is on the toe side of the CG. That creates a slight gear effect which acts to slightly tilt the spin axis into a tiny bit more draw. But it only works when you hit the ball on the center of the face so that center impact is now a little on the toe side of the CG that has been moved by the weight in the heel. How much draw bias you can get from heel weighting depends completely on how much weight you move into the heel. Moving 25 grams of the head's mass over to the heel moves the CG less than 1/4" toward the heel. Putting only 10-12 grams in the heel only moves the CG around 1/8". Hence for the golfers who are not that consistent with face impact position, a draw bias may work one time when they hit the ball on center but not the next three times when they hit the ball 1/4" off center toward the heel. This is precisely why draw bias really only works consistently well for very good golfers and not at all for the many millions who are average to less skilled players.
  2. tww

    MOI

    MOI of the head and accuracy with the club are two totally different things and not at all related to each other. We've done a lot of hit testing as well as FEA impact modeling in this area of head performance over the past many years to know a good bit about this. In short, it takes a difference of in the order of 800 g-cm2 or more in the MOI of a driver head before most golfers are going to visibly notice a real performance difference in an off center hit. In other words, if you have one driver with an MOI of 4200 and another at 5000 there is not going to be very much in the way of really noticable difference in the off center hit performance. But if you get one head at 3800 and the other at 5000, you will see visible differences. Also as you referred to Frank Thomas' comment in your post, he's right in saying that once you get to an MOI of 5000 with the driver, anything more is really not going to be noticeable. However another reason for this is because if you are trapped by the USGA Limit of 460cc and if you are forced by length to swingweight matters to keep the driver head weight at no more than 205g, it's almost impossible to design a driver head with an MOI above 5400. So in that sense Frank's statement is correct because it just isn't feasible to create a driver with an MOI significantly above 5000. Beyond the MOI, it is a fact that the face design of the driver can have much more of an effect on off center hit performance than another 800 g-cm2 in the head's MOI. There are some variable thickness face designs which are really good when it comes to keeping the COR of the face for off center locations as high as possible. Variable thickness faces work by allowing the face to flex inward a little more in the off center hit positions. And when the face can flex inward a little more in the off center hit positions, the COR there will be higher and from it, the off center hit will not lose very much in the way of ball speed. IN other words, it is very possible to design a 400cc driver with a 4000 MOI with a good variable thickness face that can offer better off center hit performance than a 460cc driver of 5000 MOI with a uniform thickness face. Now as to accuracy with a driver, there is nothing other than the face angle that can be designed into a driver head to bring about better accuracy. Nothing with CG, nothing with the MOI, nothing with the face design or COR has anything to do with accuracy with a driver. Accuracy is a product of the golfer having exactly the right length, face angle, shaft weight, shaft flex, shaft bend profile, total weight, swingweight and grip size/feel that best matches his swing characteristics. So if a golfer picks up a new driver and automatically hits it more accurately the reason for the improvement is going to be found within these above fitting specs and how different they are from the golfer's previous driver with which he was not as accurate.
  3. A golfer's ability to achieve their highest level of ON center hits or achieve their most consistent swing tempo and timing is a product of the clubs' total weight (shaft weight) + swingweight (headweight feel) + length + grip size. For better players with a later release, you can add in the shaft's overall stiffness design (bend profile) to that list. These are the elements of club FEEL for which most golfers have a specific preference, but cannot seem to QUANTIFY those feel elements all together to be able to keep finding the right FEEL when they go buy new clubs. All golfers have a unique combination of swing tempo, timing, rhythm and many golfers have theor own acquired preferences for the weight feel, headweight feel and sometimes the shaft bending feel of their clubs. Get any of these wrong in the clubs and the golfer will struggle to maintain a consistent tempo, timing, rhythm, and from that, experience more problems with swing consistency and on center hit performance. For most golfers, it is then critical to match the shaft weight, swingweight/headweight feel, length to the golfer's swing tempo, timing, rhythm, and preferences for what they believe "feels too light", "feels too heavy" or "feels just right." There are no cut and dried formulas to determine these elements precisely for a golfer. We do go on the common sense basis that the stronger the player, the more forceful their downswing transition and downswing acceleration, the heavier the shaft should/could be, the higher the swingweight should/could be. And vice versa, the weaker the player, the more passive their downswing move at the ball, the lighter the shaft should/could be, and the lower the swingweight should/could be. But there are always exceptions due to whether the golfer has acquired a specific FEEL preference over years of playing. So it is possible to find strong, aggressive swingers who prefer a lighter total weight (shaft weight) and not so high of a swingweight. Same as it is possible to find weaker, more passive swinging golfers who prefer a heavier total weight (shaft weight) and a higher swingweight. Not that often, but it can happen. This is why a good clubfitter really spends time asking the golfer if they do have specific feel preferences in their clubs - and also asking the golfer to bring in any clubs they have had which they believe FEEL good to them so the clubfitter can do various measurements. This then gives the clubfitter a good starting point for selecting the shaft weight (total weight) and the swingweight to better narrow down this search for the right feel in the clubs for each golfer. TOM
  4. Matt: In our fitting research work, we've spent a good deal of time digging into the various aspects of feel related to golf clubs. We've stayed away from the separate element of ball feel, but I do believe that we have learned quite a bit about the various aspects of club feel and their importance to fitting and club performance. Of course this could go on ad nauseum so I'll try to hit the high points of what we know from our work. We see that there can be as many as 5 separate areas of feel related to golf clubs which can be extremely important to some golfers. Those are, 1) overall weight feel (total weight); 2) headweight feel (swingweight); 2A) both 1 and 2 together (MOI of the assembled club); 3) Butt to Center area of the shaft bending feel; 4) Shaft Tip section Bending Feel; 5) Impact feel. Not all golfers have the ability to perceive differences in all of these areas of club feel. Most golfers who play somewhat frequently, regardless of handicap, can perceive differences between clubs in their headweight feel and impact feel. Most cannot really distinguish between the total weight feel and headweight feel. Not all that many can perceive differences in the shaft bending feel (3 & 4), but quite a few can detect when a shaft is much too stiff because that tends to demonstrate itself in the form of an unsolid feeling of impact when the golfer hits the ball in the center of the face. of course it is also true that IN GENERAL (but not all the time), the lower the handicap and the more the golfer hits balls and plays, the more they will have a definite perception for like/dislike for one or more of these feel areas. There is no question if the golfer has a reasonably high level of perception for any of these areas of club feel, that becomes extremely important in the golfer's like/dislike for the club(s) and very much can be the difference between success and failure in hitting the club(s) well. One of the biggest problems for a clubfitter to be able to deliver clubs to a golfer that always meet the golfer's feel preferences is being able to get the golfer to express what they like and don't like in each area of club feel in terms that can be identified in a more quantitative manner. All of us who have a certain feel preference in a club(s) tend to express our likes/dislikes in very subjective, qualitative terms. I.E."it feels too heavy", "it feels too head light (head heavy)", "it feels too stiff (too flexible)", "it just doesn't feel solid", and so on. The clubmaker has the difficult task of trying to turn such comments into real numbers, to be able to figure out "how much too heavy", "How much too head light or head heavy", "how much too stiff/too flexible and where on the shaft is it too stiff or too flexible", and so on. In our research work in club feel we are getting better at being able to teach clubmakers how to do this. Obviously, total weight, swingweight and club MOI can be measured on various specialty scales and equipment. So if we can get measurements of these parameters related to the various weight feel areas from clubs the golfer likes or dislikes, we then have a basis from which to make future recommendations. it may take a little trial and error to nail it down, but at least we can narrow the range to make the final search for the right weighting feel a little less tedious. Shaft feel wise, we also have cracked into this by being able to create graphs of a form of stiffness measurements of shafts OVER THEIR FULL LENGTH. These are what we call BEND PROFILE GRAPHS for shafts. In using such graphs of shafts it then is very possible to look at the graphs of any or all shafts the golfer says he likes, has liked or has not liked, and from that we then can know more about what shafts to recommend that would satisfy the golfer's shaft bending feel requirements. In the end, this is one huge difference between a good clubfitter and a great clubfitter because for many golfers, one or all of these different areas of feel very much can be the difference between clubs that don't perform that well and clubs that allow the golfer to play to the very best of his/her ability. TOM
  5. I just tripped across this thread and while it is not as fresh as some of the other topics, this is a very important topic. If you are talking about "technology" that is in clubs that are bought off the rack in a big box golf store, pro shop or on line, or in clubheads and shafts in general, there is no question that between the 80s and 00s, quite a number of significant advances came along that made golf clubs perform better in general. Since the 80s to name the more significant ones, 1) high MOI heads for much better off center hit performance; 2) high COR driver, fwy wood, hybrid and iron heads that most definitely have increased distance; 3) lighter and more torque resistant graphite shafts that have helped golfers gain a little or not lose much clubhead speed; 4) hybrids as long iron replacement clubs; 5) variable thickness face designs to offer better off center hit distance; But since the 00's, SIGNIFICANT new head or shaft design technology has slowed to a trickle. Many reasons for that, among them limits in the rules by the USGA coupled with huge golf club companies who have used up pretty much everything that could be invented to advance the performance of a clubhead or a shaft. But there very much is one other golf club technology that has been hugely advanced in the past 15 yrs. It is also a golf club technology that very, very few golfers have ever tried or been exposed to because it simply is not offered by any of the big golf club companies who sell their clubs through retail golf stores, pro shops or on line. That technology is PROFESSIONAL FULL SPECIFICATIONS CUSTOM CLUBFITTING. What we now know about fitting golfers with the best equipment to match to their size, strength, athletic ability and swing characteristics today completely dwarfs what was known about fitting 15 yrs ago. Yet so few golfers have ever been exposed to this chiefly because professional full specifications custom fitting is only offered and performed by a small number of independent custom clubmakers around the US and the world. We're talking about a Clubfitting Technology that fits every one of the 13 key specifications of golf clubs for all 14 clubs in the bag to each individual, different golfer. Not to be confused with so called fitting that tries to offer a narrow choice in 2 or 3 specifications and for the driver only or a fitting cart in the hands of a person who knows virtually nothing about fitting. Quality full specs fitting CANNOT BE DONE BY BIG BOX RETAIL STORES OR PRO SHOPS unless they actually build every club they sell from scratch so that each one of the 13 key specs for each club are fit and built to the precise playing needs of each golfer. A HUGE reason that golfers like JBones have not seen any real improvement from buying clubs with the new club technology of the past 30 yrs is because they bought those clubs off the rack and were never fully custom fit for those clubs. A SECOND reason that golfers like JBones have not seen any score improvement is because not only were they not professionally fit for their woods and irons, but they were never fit for their wedges and putter - the clubs that more directly affect one's score. Golfers who have taken the leap of faith to find a GOOD, EXPERIENCED CLUBFITTER know what I am talking about. Those who haven't will probably go on thinking that I'm nuts and that I don't know what I am talking about. But it is an indisputable fact that the very best golf clubs for any golfer will come from the brain and hands of a good, experienced clubfitter who can fit and accurately build every club for every one of the key fitting specifications to each individual golfer's combination of size, strength, athletic ability and swing characteristics. TOM
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