Head Weights, Shaft Weights and Balance Points – Oh My!

Why Drivers Vary in Length and Swingweight

Do you ever wonder why drivers are a particular length or swingweight? And why they aren’t necessarily uniform throughout the industry? The answers to these questions might be more complicated than what they appear. No, we are not going to uncover a conspiracy, rather break down the components of how head weight, shaft weight and balance point directly affect what length and swingweight your next driver (or customer’s) should possibly be made to.

What is the typical driver today?

In the next year the typical driver will start to vary greatly, but for now let’s say the average driver length is 45" long and equipped with a 65g shaft and 50g grip. Lastly, the average driver head will weight approximately 200g. Instead of calling these standards, it is better to establish these as benchmarks.

Another important consideration is the shaft installed into a 45" driver isn’t the same length but shorter for two reasons. The club length is measured from the ground line up to the edge of the grip cap along the back side of the shaft, which factors in the extra material at the end of the grip (approximately a quarter inch). Secondly, few heads exist today where the shaft goes through the bottom of the sole but stops at an arbitrary position above the ground line. In the modern 460cc driver, the shaft now rests close to 1 9/16" above that ground line meaning that the cut length of a shaft for a 45" driver is 43.19".

For clubmakers out there, you are used to purchasing graphite shafts that are for the most part 46" long. This means you are lopping off on average over 2.5" of material from the golf shaft. So not only does the shaft you purchase becomes shorter, but it also becomes lighter.

Need help calculating the golf swing weight based on the length, height weight, grip weight and shaft's weight and balance point? Try using Hireko's Golf Club Building Swingweight Calculator.

What’s this mean to the consumer?

Most manufacturers will establish a standard set of specifications for a driver. This specification will be built around one shaft to create a certain swingweight with a particular weight head. Long are the days were a shaft is available with just the stock option. Now customers have a slew of custom shaft options to choose from so picking and choosing another shaft other than the stock option could alter the swingweight and eventual stiffness of the club as most manufacturers only produce their heads in only one weight option.

How Shaft Weight Affects the Swingweight

One of the many factors that influence swingweight is the weight of the shaft along with head weight, grip weight and club length. In the following diagram we shall see how this works.

We already stated that the shaft is shorter than the club or in this case 43.19". Let’s say the balance point of the shaft is in the center of the shaft for starters, but we will revisit shaft balance point later. A swingweight scale pivots around a point located 14" from the butt end. The balance point of our shaft in this situation hangs over the fulcrum point by 7.75". Therefore the weight of the shaft adds or contributes to the swingweight the same as if it were head weight.

Driver swingweight diagram

Every swingweight is equal to 50 gram-inches. That means for every 6.5g of shaft weight with a balance point 7.75" beyond the fulcrum changes the swingweight by one point. The 6.5g only applies at this length as it will become increasingly more the shorter the club / shaft are. The following chart shows what will happen if we have a 200g head and 50g grip with the modern 460cc 45" driver.

Raw Shaft Weight Grams	Cut Shaft Weight Grams	Swingweight Measurement
48	45.5	C8
55	52.0	C9
62	58.5	D0
69	65.0	D1
76	71.5	D2
83	78.0	D3
90	84.5	D4
97	91.0	D5
104	97.5	D6
111	104.0	D7

As you can see, the 65g cut shaft, which started out as a 69g shaft, yielded a D1 swingweight. While this is not a standard, it is a common swingweight. If we were to use a super lightweight shaft (45g), we would see a reduction of 3 swingweight points and if we used 105g steel or graphite shaft, then the swingweight would increase to D7 at the same length.

Obviously the clubmaker has the options to add weight to the head, alter the length or change grip weight to create a specific swingweight. This is one of the reasons why certain manufactures might have D2 as their standard swingweight or they make their length 45.5" instead of 45". Shaft weight has a definite influence on swingweight.

Why is this important? Shaft manufacturers make raw uncut shafts for a variety of clubhead manufacturers who all have different ideas on how their club should be made. The shaft manufacturer who produces an open sourced shaft (one you would find in any number of component catalogs like Hireko’s) has to figure what flex to build into each model. That is a tall order as not all manufacturers will use that same shaft to be built with the same head weight and length. This is opposed to proprietary shafts were a shaft manufacturer might create a specific shaft to go into one particular model and only built to one standard stock length.

Now, this is important to understand. Since shaft manufacturers cannot dictate what length and swingweight the clubs are assembled to with their products, they have to know that manufacturers typically build to a narrow swingweight range. By knowing this, the flex of the shaft can be built into the design. However, if the swingweight of the club is lower then D1, and then the shaft flex becomes progressively stiffer. Conversely, the higher the swingweight of the club over D1, then the more flexible the shaft becomes.

This is only true if standard grip weights (50g +/- 5g) are being used. But shaft weight alone is not the only consideration as the final swingweight is also tied to the balance of the shaft.

Balance Point – The Monkey Wrench into the Swingweight Equation

As mentioned before, the balance point of the shaft is not always located at the center of the shaft. Actually it is rarely there as most shafts for driver have a balance point that is approximately 52% from the tip of the shaft. Shaft balance points in driver shafts range from 48% from the tip to 56% of the length of the shaft. Shafts that have a balance point less than 50% are considered tip heavy and rare in driver shafts. Center balanced is where the shafts balance point is exactly in the middle. Lastly, if the balance is more toward the butt or the percentage is higher than 50%, then those shafts are considered butt heavy or counter-balanced shafts.

An 8% range doesn’t sound like much, but over a 43.19" shaft can be a 3.5" range. Using our example before with the 200g head, 50g grip and 45" length, let’s now look at what happens to the swingweight.

Raw Shaft Weight	Cut Shaft Weight	Shaft Balance Point Percentage Swingweight Measurement
Grams	Grams	48%	52%	56%
48	45.5	C8.7	C7.2	C5.6
55	52.0	C9.9	C8.1	C6.3
62	58.5	D1.0	C9.0	C6.9
69	65.0	D2.2	C9.9	C7.4
76	71.5	D3.3	D0.8	C8.3
83	78.0	D4.5	D1.7	C9.0
90	84.5	D5.6	D2.6	C9.7
97	91.0	D6.7	D3.5	D0.4
104	97.5	D7.9	D4.5	D1.1
111	104.0	D9.0	D5.4	D1.8

The most popular weight range of shafts today for drivers is in the upper 60g range. Using the same head, grip and length, you can see nearly a 5 swingweight point differential just by the balance point change. To put that in perspective, the 5 swingweight point differential has nearly the same effect as a 35g shaft weight change (when the balance point is in the shaft’s center).

Unlike weight, which manufacturers publish a specification, balance is point is not one of them you will ever find. So you may have no idea if the shaft is tip heavy, center balanced or butt heavy without buying it and measuring it yourself. There is one source and that is the Hireko’s Dynamic Shaft Fitting Addendum where shaft balance points are listed in chapter 2 on current shaft models.

The Creeping Length Syndrome

Clubmakers and savvy consumers get upset with what some call the disappearing loft syndrome of irons as they seem to get strong or less lofted year after year. I don’t have time to go over that subject in this article, but I wonder if you haven’t paid attention lately to a lot of name brand manufacturer’s drivers who literally drive the market. The lengths are creeping up slightly or becoming progressively longer. Soon, 45.5" or even 46" may be the new normal.

If you do any club repair work and weigh some of the new drivers on the market, you find they still weigh @200g gram as mentioned before. But you wondered how they were able to make the length 45.5" or 45.75" and still get the proverbial standard D1 swingweight. If you paid attention, now you know the reason for it. Some of the shafts the manufacturers are using may have shaft models that are intentionally counter-balanced, to allow the use of longer length driver without having to reduce head weight. An example of this would be SK Fiber Tour Trac 55 series. The other trend is toward lighter and lighter shafts. Many of the new shafts in today’s drivers are tipping the scales in the 50 gram range instead of the 60g range since titanium drivers exploded on the market. I’ll also give you a head’s up for next year, more and more shafts are trending to weights in the 40g range.

What Should Be the Specifications for Your Next Driver?

If you are in the market for a new driver in the immediate future, then you may want to pay close attention. What is the reason for a new driver? For most golfers, it is the quest for more distance. If that is the reason a new driver is on the horizon, there are only a few ways to accomplish that. One way is going either longer, lighter or both. Lighter and/or longer provides more leverage with less effort and can increase speed and distance.

Hireko’s standard length chart or published recommended length shows that the men’s standard length is 45″ (44″ for women). This was based on using Hireko’s house brand shafts such as Acer Velocity which weighs 69g. With the standard Karma Velour grip, the swingweight come out in the normal swingweight range. Again, every manufacturer must establish their own internal standard whether you agree or not.

However, if you are looking to upgrade to a lighter shaft or a different model, you may want to reconsider the length if you want to maintain a standard swingweight and shaft flex. The following chart will provide some difference scenarios based on the common shafts weights and balance points using the modern 460cc driver weighing 200g and using a common 50g grip.

Cut Shaft Weight (Grams)	Driver Length (Inches)	Swingweight Range
45	46	D0-D3
45	45.5	C8-D1
55	46	D1-D4
55	45.5	C9-D2
65	45.5	D0-D4
65	45	C7-D1
75	45.5	D1-D5
75	45	C8-D3
85	45	C9-D5
85	44.5	C7-D2

Conclusion

There is no way of going over every scenario possible, but hopefully this helps explain why you might consider a different driver length based on the shafts that are common in the market today. By closely examining trends and making accurate measurements, clubmaker’s are able to offer drivers that may help you on your way to longer and hopefully straighter drives off the tee!