Wishon: Shaft frequency can be misleading
Numerous times I have read posts on GolfWRX from golfers who persist in selecting a shaft on the basis of a butt frequency measurement. In viewing new shafts that come on the market, many golfers believe as long as the new shaft has the same butt frequency as their current shaft, the shaft’s stiffness design will match their swing.
Unfortunately, there is a lot more to the stiffness design, stiffness performance and the stiffness feel of a shaft than a single butt frequency measurement. In other words, it is quite rare for two shafts with the same butt frequency to be the same stiffness design over the full length of the shaft. And equally, it is quite common for two shafts to have the same exact butt frequency measurement but be completely different in their stiffness design over the rest of the shaft.
Here’s a couple of examples to illustrate this point. First, let’s take a look at the full-length stiffness design of two shafts for drivers and woods, both made by the same company.
Note: All zone frequency measurements performed for our TWGT Shaft Bend Profile software are taken using a 454-gram tip weight so that we can obtain measurements all the way to the tip section of the shaft. With only a 205-gram tip weight, it would not be possible to obtain the measurements for the lower center to tip section of the shaft. Using a 454-gram tip weight lowers the actual frequency measurement compared to what the measurement would be using a 205-gram tip weight.
The two above shafts with their same 180-cpm butt frequency measurement, if done with a 205-gram tip weight, would both have a frequency measurement of 254 cpm. But the point is the same regardless of the frequency measurement method.
Here are two shafts which if measured only for the butt frequency, would lead a golfer to believe that they have the same flex or same stiffness design. Yet in looking at the full-stiffness design of both shafts, these two shafts may have the same butt frequency measurement, but they could hardly be more different in terms of their overall stiffness design. These two shafts in the hands of the same player would result in a completely different stiffness performance and stiffness feel — yet if the golfer were to look at the shafts by only referencing the single butt frequency measurement, the conclusion would be that they have the same stiffness.
This is not an isolated case. Within the 2,100 different shafts in our Shaft Bend Profile software, there are too many examples to list that are exactly like this — shafts that have the same butt frequency measurement but are completely different in their design, performance and feel.
The same thing exists within iron shafts, which is an area in club fitting that many golfers make their shaft selection decision based on comparing the butt frequency measurements. Let’s take a look at an example of two iron shafts with the same butt frequency.
What’s interesting when looking at the full-stiffness measurements of these two S flex iron shafts is that within the world of shafts, these two shafts may have the same butt frequency but they are almost as different in their stiffness measurements for the rest of their lengths as they possibly can be. Were the same golfer to play both these shafts, the Rombax S would feel like a telephone pole compared to the ProLaunch Red S. Yet both are S flex and both have the same exact butt frequency.
This matter of judging shaft stiffness, performance and feel on the basis of the butt frequency only can rise up to mislead golfers in the other direction as well. Let’s take a look at this next pair of shafts, a Cleveland Gold 60 S and the Fujikura Blue 004-R.
Remember that these frequency measurements in the Bend Profile software are done using a 454-gram tip weight. The butt frequency of these two shafts if measured with a 205-gram tip weight would be 254 cpm for the Cleveland Gold 60-S and 244 cpm for the Blur 004-R.
Looking only at the butt frequency measurements, one would think that this 10 cpm difference in butt frequency with a 205-gram tip weight, or 7 cpm difference with a 454-gram tip weight, would most definitely be the reason the Cleveland Gold is an S flex and the Fuji Blur an R flex.
But take a look at all of the rest of the relative stiffness measurements after the butt frequency measurement. The 2- 3-5 differences in frequency for the 26 inch, 21 inch and 16 inch positions on the shaft are so small to be insignificant in terms of a stiffness difference in two shafts. Even the 13 cpm difference in the very tip end of the shaft is extremely small in terms of a performance or feel difference.
For all intents and purposes, beyond that single butt frequency measurement, these two shafts are so close in stiffness design to each other that only a very small number of very feel sensitive players could ever tell the difference in performance or feel between these two shafts.
Another interesting point from this comes to mind when you think about sorting shafts by their butt frequency as a way to make sure all the shafts in a set have the same stiffness. Think about that based on what you have seen in the previous graphs which show shafts of the same butt frequency but totally different over the rest of the shaft, and this above graph which shows two shafts that are completely different for their butt frequency yet so very close to each other over the entire rest of the shaft.
But what about that 7 cpm difference in the butt frequency measurements? Wouldn’t a golfer feel that difference even if the rest of the two shafts are so close to each other in their stiffness design?
Consider this: In the installation of wood shafts into a driver and fairway woods, almost all of that very area where the butt frequency measurement is performed is cut off the shaft when the woods are built to conventional playing lengths. Most shafts for woods are made with a raw uncut length of 45 inches or 46 inches. When installed in most driver heads, to achieve a playing length for the driver of 45 inches, in the area of three inches is cut from the butt end of the raw shaft after installation.
That means the position on the shaft where the butt frequency is measured is now just two inches from the end of the grip. Do you think that last two inches of the butt of the shaft bends very much during the swing? No, it doesn’t, which in turn even further negates the 7 cpm difference in butt frequency between these two shafts in our above example.
Shaft stiffness design selection has to be made not just on the basis of the butt frequency, but on the basis of the stiffness of the full length of the shaft. So the next time you hit shots with a club that you know has the same frequency but the shaft feels or performs different, you now know why. Or the next time you hit shots with two clubs that you are sure have different stiffnesses yet feel and perform the same, you know that reason as well.
Bottom line? If you are serious about your shaft selection, you need to be working with a good, experienced custom club maker who is cognizant of these factors and who is able to show you the actual differences and similarities of the stiffness design of the whole shaft.