Sunday, February 10, 2013
What really does control accuracy in a driver?
There always seem to be questions from golfers asking what driver is more accurate/straighter. It is evident that a number of golfers believe that driver accuracy is a product of the design technology of the driver head itself – as if to say this Brand and that Model of driver is straighter so if you buy it you will hit the ball straighter. The only driver club HEAD specifications that have anything to do with accuracy are Face Angle (huge effect), the Lie Angle (small effect), the toe/heel weighting (small effect that really only works for GOOD golfers) and the MOI of the driver head about the axis of the hosel bore (tiny effect, one to forget about). But these four clubhead elements are not really “design characteristics” unique to any company’s design technology – they can be had on some companies' driver head designs that offer a wide range of fitting options. Accuracy is chiefly a factor of the face angle plus a number of other assembly specifications of the driver and how they all FIT the golfer’s swing characteristics. Distance and Forgiveness? Sure, those performance elements can be designed to be a little different from driver head design to driver head design. So when you are asking who has the longest / most forgiving driver, you can talk a little about the brand and model – but keep in mind as well that maxing out your distance and improveing shot consistency are also a HUGE part of fitting. Without question the Clubfitting factors that control driver accuracy do not all have the same importance to accuracy. ALL OF THEM can work differently for different golfers, depending on each golfer’s specific swing characteristics. What brings about better accuracy in a driver for one golfer may or may not do that for another golfer because of differences in each golfer's swing that causes each golfer’s accuracy issues to begin with. This is why you cannot say "go try this driver or that shaft and you'll hit it straighter because it worked for me." What works for you probably has nothing to do with what will be best for any other golfer because your swing is different than other golfers' swings. That's why fitting is SO IMPORTANT to ensure each golfer can play to the best of their ability. One other thing before I explain driver accuracy. When a golfer buys/borrows a new driver and immediately achieves better accuracy with that driver, it is because one or more of the following accuracy elements happens to fit the golfer’s swing better than did those same elements in the previous driver. It isn’t just because of the brand or the model name of the driver. Following are the specifications which control accuracy RANKED IN ORDER OF IMPORTANCE TO ACCURACY. Some golfers, depending on their swing or sense of feel, might find one or more of these more important than others. Main point, for the majority of golfers, this is the order of importance for driver accuracy. Get all these from #1 to #7 fit correctly to YOUR size, strength, athletic ability and swing characteristics and you will hit the ball as accurately as possible. 1.Face Angle 2.Length 3.Swingweight (MOI of the Assembled Club) 4.Shaft Weight / Total Weight 5.Shaft Flex/Shaft Bend Profile 6.Toe or Heel Weighting (Fade/Draw Bias Weighting) 7.Lie Angle 8.MOI of the Driver head about the Hosel Bore If you want to stop now to keep your reading short, you can do so. If you want an explanation of each of the above accuracy factors and how they all can be fit to help you achieve the best accuracy possible, then I welcome you to read on. 1.Face Angle Face Angle has the most effect on driver accuracy because it is a degree for degree correction for the swing path and/or face angle delivery of the golfer that causes the predominant misdirection problem. For each 1 degree CHANGE in the face angle from the face angle the golfer used previously, the ball flight moves 4 to 5 yards sideways based on a carry distance of 200 yds. For example, a golfer with a swing speed of 85-90mph who slices the ball on average 25 yards left to right who changes from a 0* square face angle to a 3* closed face angle will see his average slice reduce to 10-13 yards. The higher the swing speed, the more the misdirection correction for each degree of face angle change. Face Angle is THE #1 game improvement factor for accuracy with the driver and fairway woods. 1.Length TWGT has done a serious engineering study of the effect of driver length on the golfer and the golf swing. There is no question, the longer the length of the driver, the higher the load and the more stress the club puts on the golfer and certain specific swing movements. In short, longer driver lengths cause the swing to break down sooner and more dramatically. The more the golfer fights the following swing issues – over the top, outside in path, earlier release, quick tempo – the more that a longer driver length in excess of 44” can make these swing problems worse as well as much more difficult to correct. The more that a golfer has these following swing characteristics – inside out to square path, later to very late release, smoother controlled tempo – the more they COULD use a driver length of 45 to 46” and have decent results. I say COULD, not SHOULD. The reason is because for ALL but a very small number of golfers, the longer the length, the higher the percentage of off center hits. And when you hit the ball off center, you lose ball speed and you can lose accuracy as well. Perhaps the most common sense and compelling proof of the matter of driver length vs control and accuracy is the fact that for many years, the average driver length on the PGA Tour has been 44.5” and not the 45.5 to 46.5” that is standard on virtually every OEM driver made and sold off the rack to male golfers. The PGA Tour represents some of the best golf swings and best golf athletes on the planet. If THEY feel they need a shorter length to maintain control with their skill level, what does that say about all the regular golfers from low single digit on up to achieve the best driver results with a driver bought off the rack with a longer length? Seriously guys, these driver lengths sold off the rack are not doing anything good for 98% of all golfers. 1.Swingweight (MOI of the Assembled Club) All golfers have their own unique makeup of strength, athleticism, and most important, their own SWING TEMPO, TIMING, RHYTHM. Give a golfer a club that feels too light in the headweight feel for their swing tempo/timing/rhythm and their tendency will be to get MORE QUICK, to fight their tempo, to bring out more of an “over the top” swing error. If any of these happen because the headweight feel is too light for the golfer, accuracy will most certainly suffer. There is most definitely a headweight feel that will allow each golfer to swing with more consistency and with more comfort so they feel they are not fighting their swing tempo or laboring to swing the club. Most golfers reference a headweight feel in a club by its SWINGWEIGHT. However, one specific swingweight is not going to deliver the same headweight feel in all combinations of driver length, grip weight and shaft weight. In other words, D2 at 45” with a 70g shaft and 50g grip does NOT deliver the same headweight feel as D2 at 44” with a 55g shaft. Some clubmakers use the MOI of the fully assembled club to deliver the same overall swing feel in a golf club at different combinations of length, grip weight and shaft weight. If swingweight is used, the golfer has to be aware that as he changes the length, grip weight and shaft weight in his driver, he may have to experiment with different swingweights before arriving at the one that allows HIM to achieve the most consistency and comfort so they feel they are not fighting their swing tempo or laboring to swing the club. 1.Shaft Weight / Total Weight The weight of the shaft controls the total weight of the golf club more than any other component. Shaft weight/total weight acts in combination with the headweight to deliver the overall weight FEEL to the golfer. And, like swingweight, the total weight is also an important element to be fit to each golfer’s unique makeup of strength, athleticism, and most important, their own SWING TEMPO, TIMING, RHYTHM. However, for MOST golfers, changes in the swingweight (headweight feel) are noticed more than changes in the total weight. Of course, if the golfer changes from a 120 gram steel shaft to a 75 gram graphite shaft, they will notice the total weight change from that shaft weight change. But if the golfer changes from a 65g shaft to a 55g shaft, or changes shaft weight by 15g or less, not all golfers will notice that effect on their swing tempo and timing and rhythm. Shaft weight/total weight IS important to fit golfers with the best overall weight feel to help contribute to a more consistent swing tempo and better accuracy. But you can be off in the total weight a little with a golfer and as long as the swingweight (headweight feel) is right for that golfer’s swing tempo/timing, his accuracy will be good. But mess up the swingweight (headweight feel) and you will see some severe problems with accuracy and off center hit frequency. 1.Shaft Flex / Shaft Bend Profile It is true for SOME golfers, definitely not all and definitely not the majority, that a shaft that is too flexible for their swing can promote more of a draw and a shaft that is too stiff can promote more of a push or fade. But in no way does this happen for the majority of golfers nor does it cause a severe hook or slice. If a golfers has experienced a definite hook or slice from a change in the shaft flex/bend profile, most of the time it was something else that changed along with the shaft change that brought about the dramatic hook or slice. Most likely culprit is the swingweight (headweight feel) or possibly the combination of swingweight and total weight that changed when the golfer changed shafts. However, it is possible for some golfers who have a very refined sense of feel for the bending action of the shaft to suffer a definite accuracy problem from a shaft flex/bend profile change. For such golfers, when they feel the shaft bending more than they want, their reaction can cause swing mistakes which result in the more severe accuracy problem. Likewise, when a golfer with an extreme sense of bending feel uses a shaft that is too stiff, a typical reaction is to swing harder to make the shaft bend more and achieve the feel they prefer. And that too brings about swing errors that can result in an accuracy problem. In both cases, the golfer blames the shaft flex for the accuracy problem. In reality it is the golfer’s own reaction to the less favorable flex feel, sometimes conscious, sometimes sub-conscious, which brings about the swing errors that result in the accuracy loss. Bottom line? Always fit the shaft so the flex and bend profile are well matched to the golfer’s swing AND sense of feel and the shaft cannot be a problem for accuracy. 1.Toe or Heel Weighting (Fade Bias or Draw Bias Weighting) It was in Cochran & Stobbs’ milestone 1968 book that the concept was first introduced that adding weight to the heel could enhance a draw ball flight. Along with the late Elmore Just of Louisville Golf Company, in 1987 Elmore and Tom Wishon designed and built a laminated maple driver head with weight in the heel to test this concept. Later in 1995 Wishon had the chance to design an aluminum body driver with weight in the heel to further test the concept. Both these driver heads were the first commercially developed wooden and then metal Draw Bias weighted driver heads. Long story short, they found from all their work that it takes more than 25 grams of the head’s total mass to be positioned deep in the heel to even begin to see the ball draw. At 40 grams or more, the heel located weight has now pulled the center of gravity far enough off the center of the face toward the heel so that if the golfer hits the ball dead center on the face, ball speed is lost and with it, distance is lost. Bottom line? None of the OEM drivers that allow weight movement from heel to toe allow you to move more than 25 grams from one side of the head to the other. Draw Bias or Fade Bias (DB / FB) weighting is good for really good ball strikers to tweak their ball flight so as to encourage a slight draw or fade or to reduce a nagging draw or fade without having to manipulate their path or face angle. But Draw Bias or Fade Bias weighting is NOT for correcting a slice or a hook because it cannot affect the curvature of the ball anywhere near as much as can a Face Angle change. DB or FB work by moving the CG off the center of the face so that an on center hit now causes the head to twist a little, and in so doing generate a small gear effect to slightly tilt the axis of backspin rotation of the shot. Face Angle is a degree for degree correction of how many degrees the swing path and/or delivery of the face by the golfer has caused the face to be open at impact. If you have a very consistent delivery of the club to the ball and you want to slightly tweak the shape of your shot, use 25 to 30 grams of the head’s weight in the heel (draw) or toe (fade) and you will get that very slight ball flight shape change. If you slice or hook the ball, use a substantially different face angle along with a shorter driver length. 1.Lie Angle Lie angle is much more of an accuracy factor as loft increases in the set. While having the perfect lie for YOUR swing is important for every club in the bag, it is much more critical for accuracy in the mid to short irons and wedges than it is with the driver. Yes, it can be said that the smaller misdirection angle of an ill fit driver lie is magnified by the greater distance you hit the driver. But in testing, an ill fit lie angle doesn’t result in nearly as much of an accuracy problem with the driver as it does with the clubs that have much more loft. One big reason is because the acceptable target area for accuracy success with the driver is MUCH WIDER than it is with the irons. Most fairways are far wider than most greens.But it is also true if the driver if off by 4* of lie and the 9 iron is off by 4* lie for the golfer, the combination of the much greater misdirection angle of the off lie 9 iron with the much greater spin of the 9 iron contributes to that shot flying much farther off line at its shorter distance than the driver at its greater distance. Bottom line? If you’re much shorter than average and you see the toe of the driver sticking way up at impact, do hunt for a flatter lie driver or a driver that can be adjusted for a much flatter lie. Everyone else? Don’t worry about driver lie because any possible misdirection problems in the driver can usually be offset by a different face angle. In a world where bending titanium drivers to custom fit the lie is nigh on impossible, that’s the best advice I have for driver lie. 1. MOI of the Driver Head About the Hosel Bore This one’s a real yawner. Not only is its explanation complicated and boring, but it just is not a factor in accuracy fitting with drivers today. Some people like to say that the higher this MOI, the more difficult it is for the golfer to rotate the face back around to be square at impact. And so if this MOI is real high in a driver, a golfer could start slicing the ball because they can’t rotate the face back around to square at impact. Doesn’t really happen that way. For one, almost ALL drivers today have the same MOI about the hosel bore axis. 98% of all drivers today are between 440-460cc with very, very little variation in how far the Center of Gravity is from the center of the hosel bore. And that’s the parameter that determines just how high or low this MOI about the hosel bore axis is. Bottom Line? If you slice the ball, you can hunt for a sub-400cc driver to try to get this MOI Lower to help. But rather than do that, just go get fit for a driver that is shorter and has a face angle that is more closed than the face angle on your present driver. Do that and you will have done FAR MORE to reduce your slice than even a 200cc driver could do from its lower MOI about the hosel bore axis. Golfers, do all these things I just outlined and you will hit the ball as straight as your swing can allow. Better yet? Go find a good, competent, experienced custom Clubmaker who is schooled in all these things and let HIM do it for you in a fitting and custom driver for YOU and YOUR SWING.