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Wishon: The practical facts about spin and shaft design
It is a great education as a clubhead and shaft designer to scan through GolfWRX forum posts to listen to what golfers think about their equipment. One of the areas that seems to have developed momentum on GolfWRX is how many golfers react to a backspin measurement on a launch monitor. They try to find a shaft that can enable them to get their spin number lower without first taking the time to determine if they do in fact have a spin problem.
Here are the facts I’ve learned about driver spin in my career, in which I’ve spent countless hours designing clubheads, shafts and fitting golfers.
- Spin outputs from some launch monitors can be inaccurate and inconsistent
Only the TrackMan and FlightScope launch monitors have the ability to read the amount of backspin on a shot with reasonable accuracy. Other launch monitors use various means of pickup (camera, ultrasonic, laser, etc) which simply cannot record spin with a reasonable level of accuracy ore repeatability. Some just simply calculate the spin from the golfer’s ball speed!
Accurate backspin measurement on a golf shot is a highly complex operation. The output for spin is in revolutions per MINUTE. Yet a launch monitor has only a fraction of a second in which to measure how much the ball is spinning upon leaving the clubface. This means with every launch monitor, a math calculation has to be incorporated with the amount of spin “seen” in a fraction of a second to come up with the RPM measurement.
During the time the other launch monitors actually “see” the ball spin, the ball does not even complete one full revolution. Therefore, the spin recognition means has to very accurately measure how much the ball actually rotated during the time it was being “seen.” If the device misses the amount of revolution by say, 10 degrees out of a full 360 degree rotation, by the time the math calculation is done to output an rpm measurement, the final spin measurement can be way off.
TrackMan and Flight Scope use phase array pulsing Doppler radar to measure spin. Both units shoot a radar beam at the ball from behind, and thus are able to pick up data from the ball’s movement for several feet after impact. This is in comparison to a camera based system which only sees the ball over a couple of inches after takeoff, and explains why the TrackMan and FlightScope launch monitors are more accurate in their spin measurement.
- Most golfers hit range balls on a launch monitors, not premium balls
When is the last time you hit premium quality golf balls on a launch monitor? The majority of operations use range balls with their launch monitor analysis.
Most range balls are one-piece and rarely have similar spin characteristics to the premium balls that golfers typically use when they play. Range balls also suffer more wear from getting hit a lot more times than premium balls. Add it all up and it is nearly impossible for a golfer to try to make valid conclusions about their spin measurements when hitting worn range balls on launch monitors that do not have the ability to accurately measure backspin.
There most definitely is a difference in spin between different models of premium golf balls. To get the most accurate and valid spin measurement for each golfer’s game, it only makes sense to use the ball you typically play and do it with either a TrackMan or Flight Scope launch monitor.
- The best way to determine if you have a spin problem is to observe the flight of the ball, not by reading the spin output from a launch monitor
Just because a tour player’s driver spin is in the low 2000-rpm range does not mean that if yours isn’t, you have a spin problem that is harming your game. The optimum amount of spin for each golfer differs depending on clubhead speed and angle of attack. The slower the clubhead speed, the more spin is needed to generate enough lift under the ball to help keep it in the air to carry farther. Likewise, the higher the clubhead speed and ball speed, the less spin is needed to generate enough lift under the ball to help keep it in the air to carry farther.
The following are data charts from TrackMan that show their findings for what are the optimum driver launch parameters are for different combinations of clubhead speed and angle of attack. From TrackMan’s research, it is easy to see that spin has to increase as clubhead speed slows and the angle of attack is more downward. Charts are offered for optimum CARRY distance as well as for optimum TOTAL DISTANCE as per the conditions of the fairways and their conduciveness to more or less roll of the ball after landing.
Whether a golfer has too much backspin for his clubhead speed and angle of attack depends on the ball flight shape as the ball flies through the air. More serious, higher ball speed golfers need to learn how to visually identify what a shot hit with too much spin looks like rather than to make conclusions based only on a launch monitor measurement.
For shots hit with too much spin, the ball typically curves rapidly upward to a higher apex in flight, after which the ball seems to hang for a little moment at the peak of its apex and then fall more steeply to the ground. From a side view, an exaggerated graphic of the flight shape of the excessive spin shot looks somewhat like this:
A more preferred driver ball flight shape would look more like this:
There is nothing wrong with hitting the driver high, as long as the angle of descent of the ball to the ground is less than 40 degrees.
TrackMan and FlightScope have features that allow you to see the flight shape of every shot. Because they pulse the ball continually in flight from takeoff to landing and roll, its graphic rendition of the shot is accurate. This too can be a valid way to determine if your ball flight shape indicates that you hit the ball with too much spin for your clubhead speed and angle of attack.
Bottom Line: Learn to watch the flight of your shots and make conclusions about spin results from what you see before you make conclusions from what the launch monitor outputs for a spin number.
- The vast majority of excessive spin situations are caused by swing errors far more than from playing the wrong equipment, and are more often cured by changes in swing technique more effectively than from changes in equipment.
What causes the excessive spin shot? From our research and fitting observations, the two most predominant swing errors that result in excessive spin are:
- A downward angle of attack into the ball with the driver which requires the golfer to use more loft to achieve their optimum launch angle, which in turn increases spin.
- A breakdown of the wrist of the upper hand on the grip coming into impact which allows the clubhead to pass in front of the hands before impact, thus greatly increasing the dynamic loft of the clubhead and increasing spin and launch angle along with it.
The equipment change that can more effectively and more dramatically reduce higher spin caused by either one of these swing errors is a lower the loft on the clubhead. However, in the first case of the downward angle of attack, lower loft, is not really a good solution because it lowers the launch angle as well. Of the two, launch angle and spin, it is FAR better to achieve the right launch angle for the golfer’s clubhead speed and angle of attack than it is to lower the spin.
In the second case of the clubhead passing the hands to cause the high flight, high spin shot, lower loft certainly helps reduce the problem. However, it is also true that you can only lower loft so much. Rarely will you find a 6-degree or 5-degree loft driver. At the end of the day, a golfer is much better off making the effort to get rid of the higher spin/higher launch by taking lessons to improve his angle of attack or his hand-to-clubhead position at impact.
- What is a low launch/low spin or high launch/high spin shaft?
Seriously, if I had a dollar for every time I have read, heard or been asked this question, I could pay for a really nice golf vacation! If you want to know the REAL ANSWER to this question, here it is:
Any shaft that is stiffer overall or is more tip stiff than what you currently play is a lower launch shaft, while any shaft that is more flexible or more tip flexible than what you play is a higher launch shaft. In short, because the golf swing controls everything with regard to the performance of a shaft, what is a lower launch/spin shaft to one golfer can be a higher launch/spin to another golfer and vice versa.
As I have written many times, a shaft ONLY acts to change launch angle and spin for golfers who have a late unhinging of the wrist cock angle during the downswing. So the higher your clubhead speed and the later you release the club, the more you can force the shaft to be flexed forward at impact, which in turn increases the dynamic loft of the clubhead to increase launch angle and spin.
So the stiffer the shaft and/or more tip stiff the shaft in relation to your clubhead speed and point of release, the less the shaft bends forward at impact and the more that shaft becomes a lower launch and lower spin shaft. Conversely, the more flexible and/or more tip flexible the shaft is in relation to your clubhead speed and point of release, the more the shaft can bend forward at impact to generate a little higher launch/higher spin shot.
I’m sorry to tell you this, but the ONLY way you will ever know if a shaft is going to be a lower or higher launch/spin shaft than what you play is to see and compare the full stiffness measurements of the shafts using something like my company’s TWGT Shaft Bend Profile Software. Many of you have seen graph and data chart images from this program that I have posted on WRX to explain the stiffness and performance and feel differences between shafts.
Below is an example graph and data chart from the TWGT Bend Profile Software. The following chart shows shafts for a golfer with a 100 mph driver clubhead speed who has an average transition/tempo force and a late release. The shafts are listed from top to bottom in the chart for highest to lowest launch/lowest spin characteristics so that you can see how the tip stiffness of the shafts becomes the key element for offering a progressive lowering of the launch and spin for the same driver head.
In the above bend profile graph, the stiffness of all seven shafts in the butt-to-center areas is close enough that all seven could be rated for a golfer with a 100 to 105 mph driver clubhead speed with an average transition force and average tempo.
The measurements for the 21/16/11 are the tip section stiffness measurements. From top to bottom, you’ll see the tip stiffness become progressively stiffer and stiffer. Thus, among these shafts, for a golfer with a 100 to 105 mph driver clubhead speed with an average transition and tempo force, the UST HTD CB85-R will hit the ball the highest with the greatest spin. Then for each shaft that follows, this same example golfer would see a very gradual lowering of the launch angle and spin due to the increase in tip stiffness, while the butt-to-center stiffness remains the same for each shaft.
Now let’s say the 100 to 105 mph golfer with an average transition force and late release was using a Kusala Indigo 61-X, and he complained of hitting the ball with too much spin and wanted a recommendation for a low spin shaft to reduce his spin. Among these shafts, the only one that could even qualify is the Vista Tour 60-X because its tip section is stiffer. However, based on these tip stiffness measurements, the Vista Tour 60-X is only a little more tip stiff than the Kusala Indigo 61-X. The golfer using the Kusala Indigo 61-X probably would not see much of a change in launch or spin because the Kusala is already a very tip stiff shaft.
In reality, if a golfer using such a tip stiff shaft as the Kusala Indigo 61-X complains of too much spin, you could probably bet the farm that if he does in fact have a spin problem, it is because of a swing error and not an equipment deficiency.
Hard data like the above graph and measurement chart is how spin characteristics of shafts have to be analyzed. Anything else is a pure guessing game.
- Is there such a thing as a high launch/low spin or low launch/high spin shaft?
To make this easy, the answer is without question is NO, it is impossible to make such a shaft because of the different ways different golf swings cause the shaft to bend. No, nada, nil, cannot be done. Period.
The later the unhinging of the wrist cock angle and the higher the clubhead speed, the more the shaft can arrive at impact flexed forward. The more the shaft flexes forward, the more the dynamic loft of the clubhead is increased. The more the dynamic loft of the head is increased, the higher the launch angle AND the higher the spin will be for the shot.
Since it is the forward bending of the shaft that influences the dynamic loft at impact, and since dynamic loft at impact controls BOTH launch angle and spin in the same way, it is impossible to create a shaft that is either high launch/low spin or low launch/high spin.
Conclusion and Key Points
- Be more concerned about finding the driver and shaft combination that achieves your absolutely optimum launch angle and ball speed before you worry about spin. Stop obsessing about the spin number coming from the launch monitor. Please take the time to carefully analyze the ball flight shape of your shots before you make any conclusions about whether you have a “too much spin” problem.
- You never want to choose a shaft with a stiffness and/or tip stiffness design that either feels too stiff or too flexible for your individual preference for the bending feel of the shaft.
- The No. 1 way to change the amount of spin and trajectory on a shot is to change the loft of the clubhead. No. 2 is to change the ball design. No. 3 is to change the shaft’s stiffness and/or tip stiffness design, but remember; a shaft that affect a change on spin only works for players with a later and later release.
- If you truly do have a “too much spin” problem as proven by a valid, accurate observation of the flight of the ball, first check to see if you have a downward angle of attack or if you are allowing the clubhead to pass the hands before impact. If you do either one of these things in your swing, take lessons and practice hard to change these swing errors — do not buy a new club or shaft.
If you cannot overcome the swing error causing your too much spin problem, find a lower loft to help you reduce spin. If you cannot overcome the swing error causing your too much spin problem and the shaft you have fits your swing speed, transition/tempo force, point of release and preference for feel, don’t go shaft hunting to try to lower the spin on your shots. It will either have little to no effect you’ll like end up with a shaft that feels and plays too stiff.