3Jack Experiments With Shortening The Driver Shaft

One of the questions I get and I often see on message boards is about shortening the length of the driver. As most people know, the driver shaft lengths from OEM’s are usually in the range of 45-1/4” to 46-1/2” long. However, according to Tom Wishon’s booklet ’12 Myths That Could Wreck Your Game’, the average length of a driver on Tour for each of the last 5 years has only been 44-1/2” long.

The idea behind the longer driver shafts is that the longer the shaft will equate to more clubhead speed which will allow the golfer to hit it longer. The main problems I see is that the long shafts often influence the golfer’s address position and cause the golfer to make swing compensations to deal with the shaft being too long. The other problem is that even if the golfer can address the ball reasonably well, they can have difficulty timing a shaft that is long in length.

I had debated this myself, but I didn’t feel I could quite trust recommended lengths from other fitters not named Tom Wishon (or Richard Kempton http://www.theclubdoctors.co.uk/). And the book that I had read about driver shaft fitting from Wishon was his 2006 ‘The Search For the Perfect Driver.’ The book is a great book, IMO, but some of the information needed to be updated. I was not quite into his recommended length for a driver based on wrist-to-floor measurement because it came out very short in length (around 43-1/4” long). My guess is that from what I read in the book, it appeared to be based upon a golfer using a steel shaft instead of the longer graphite shaft. Steel shafts weigh much more than graphite and back then graphite shafts were difficult to figure out. But now with Shaft Bend Profile technology, there is really no reason to use steel shafts in a driver IMO.

The booklet is free and can be found here. I highly recommend reading this and it’s an easy read.

http://www.loomiscustomgolf.com/pdf/12MythsBook.pdf

Go to table 2 on page 10 and you’ll find a recommended length for a driver and 5-iron based upon your wrist to floor measurement. I determined that I need a driver around 44-3/8” long. However, there were several factors I had to consider before doing this.


DRIVERS USED



I have two Wishon 919THI drivers.

Driver #1

9° loft
58° lie angle
321 grams static weight
2,825 kg/cm^2 MOI
45” long
Aldila RIP Beta X-Stiff shaft (67 grams)


Driver #2

10° loft
58° lie angle
321 grams static weight
2,825 kg/cm^2 MOI
45-1/8” long
UST Mamiya ProForce VTS Silver 6x shaft (69 grams)

There are some minor spec differences like the loft and 1/8” difference in the length. The shafts are slightly different in weight. The Aldila RIP Beta has a stiffer butt section which makes the club *feel* stiffer and more ‘boardy.’ I felt that the loft was too low for me and the shaft was too boardy, so I got a higher lofted driver with the UST Mamiya shaft.

The idea was then to take Driver #1 with the Aldila shaft, trim it down to 44-3/8” long, match the MOI to the longer driver and analyze the effects.


MOI AND WEIGHT



There was a 1/8” difference in shaft length when I started out. The shafts had a 2 gram difference in weight. So when I started out with these drivers, their MOI with NO weight added to the head, was roughly the same at 2,790 kg/cm^2. I then added about 3 grams of lead tape to the hosel to each to get them to match to 2,825 kg/cm^2. I have determined that MOI is pretty much spot on for my optimal MOI.

I don’t have the bend profile information for the UST Mamiya shaft as that has not been added to Wishon’s database. My assumption is that the Aldila has a stiffer butt section and has a little more weight towards the tip section than the UST Mamiya shaft. Otherwise, from a weight perspective there’s not much of a difference between the two and my objectives where to figure out what differences would there be in clubhead speed and attack angle, if any.

When I trimmed the Aldila RIP Beta from the butt end to get the club at 44-3/8” long, that made the club ¾-inch shorter than the UST Mamiya shaft.

This also drastically reduced the MOI.

So the Aldila Shaft went from (w/no lead tape):

45-inches: 319 grams, 2790 kg/cm^2

to

44-3/8 inches: 317 grams, 2,680 kg/cm^2

Now remember, I want to get the MOI to 2,825 kg/cm^2. In order to get the club from 2,680 to 2,825, that meant I had to add 12 grams of lead tape around the hosel. And this is how it affected the total static weight.

Driver #1 (Aldila 44-3/8” long): 329 grams
Driver #2 (UST 45-1/8” long): 321 grams

Hence, the Aldila the shaft is shorter, but since I matched the MOI of the two clubs, the shorter club is 8 grams heavier in static weight.

Thus, if you want to trim your own driver shaft or get a new shaft and make it shorter…and IF you want to get the MOI the same as your longer shafted driver, you can do it. But you MUST take into account that the shorter driver WILL weigh more in the process of matching the MOI to the longer driver shaft.

CLUBHEAD SPEED



Even though the shorter driver weighed 8-grams more than the longer driver, according to Wishon he sees on average, approximately 1 mph of clubhead speed difference between clubs that have a 25 gram difference. So my feeling was that the shorter club weighing 8-grams more would be rather negligible with relation to clubhead speed.

In the end, I found that the difference in clubhead speed was about 0.5 to 1.0 mph between the two drivers with the longer UST Mamiya shaft being faster in clubhead speed.

My theory is this. Wishon has stated that you really don’t see a difference in clubhead speed until there’s a shaft length difference of more than +1/2-inch. So with the difference in shaft length being 3/4-inch along with an 8-gram static weight difference, that is why the clubhead speed in the shorter driver was about 1 mph slower.

The only other theory is perhaps the distribution of the weight in the shaft may have made a difference as well.


ATTACK ANGLE

I did not see any difference in attack angle with either driver. My original hypothesis was that perhaps drivers that are too long for a golfer would cause a steeper attack angle because they would feel like they have to un-cock the wrists earlier in the downswing or it would feel like they would hit the turf behind the ball.

Instead, I saw virtually no difference. I was keeping my attack angles in the -0.5 to -2.0° downward range. I will say that my shallowest attack angle, +0.8° was done with the shorter 44-3/8” Aldila driver. But I would hit shots altering between clubs and see no difference in attack angles.


SPIN RATE

It’s difficult to judge with range balls. Sometimes they would show a spin rate as high as 4,000 rpm’s. Other times the spin rate was at 1,700 rpms. I think in general my spin rates are in the 2,400 to 3,000 rpm range and I did not see any difference with either driver.


ACCURACY AND CONSISTENCY



Since the clubhead speed was about 1 mph slower with the shorter Aldila shaft and the attack angle and spin rate was the same, I really needed to see a difference in accuracy and consistency with the shorter shaft to decide if it was worth trying a shorter shafted driver.

Here is where the shorter driver won hands down. Not only on well struck shots, but with mis-hits as well. Essentially, the longer driver shaft would have the ball fly much more offline on inaccurate shots. It was much mjore difficult to control the initial direction of the ball flight with the longer driver.

What I also found interesting is the launch angle was much better with the shorter driver and the shaft did not feel boardy or too stiff.

This is peculiar because like I mentioned earlier, the shorter driver was in a lower lofted 9° clubhead that I had replaced with a 10° loft. Now the launch angle was virtually the same or within 0.5° from each other.

What surprised me was that the shorter Aldila RIP Beta shaft no longer felt too stiff or boardy. I have the shaft bend profile and in general it’s a fairly common shaft bend profile for an X-Stiff shaft, but it is noticeably stiffer in the butt section which makes the shaft feel boardy.

Recently, somebody asked Tom Wishon of the effects tip trimming, often called ‘tipping’, have on the shaft’s bend profile. Here is what Tom wrote:

There are some very predictable things as well as a little bit of weirdness surrounding what happens to frequency machine readings when you increase the tip trim on a shaft.


Quote:

In all of our work to look at this using the Auditor frequency analyzer and the same bend profile measurements that we use for all bend profile data work for our software program, most definitely all of the measurement zones from 41" down to 16" do increase in frequency when you tip trim more off a shaft. Weirdly, we have seen that when you do the 11" beam measurement, when you tip an additional amount from the shaft, the 11" measurement either stays the same or will DECREASE. This to us is VERY STRANGE. It should go up just like all the other bend profile measurement points. But it doesn't and to be totally honest with you, I don't know why and neither do any of the other shaft design experts that I have asked about this too. Logic says if you cut more of the smallest diameter part of the shaft, and then you recreate the same beam length in the measurement, at the 11" beam you should be clamping the shaft on what is now a larger diameter part of the shaft. And that means the shaft section sticking out 11" from the clamp consists of a larger diameter part of the shaft and less of the weakest part of the shaft - so the freq should be going up. In reality it has to get stiffer at the tip end when you tip trim more. You're cutting off more of the weakest part of the shaft leaving more of the stiffer part. So in reality supported by golfer hit testing, we can tell you that yes, additional tip trimming will stiffen the WHOLE shaft. why the freq analyzer shows this for the 41 to 16 beam length measurements but not for the 11 measurement, I can't tell you why.

When Wishon does their shaft bend profiles, they measure the frequency of the shaft in 6 different locations from the 41 inch mark (butt end) to the 11 inch point (tip end). For iron shafts, they measure 5 different locations starting at 36 inches to 11 inches because iron shafts are shorter in raw length than driver shafts.

Wishon’s point is that when a shaft is tip trimmed, the very bottom measurement of the tip section gets softer and the rest of the driver shaft gets stiffer. Why? They do not know at this point.

So my theory is when you trim more from the butt end, perhaps the opposite happens with the very end of the butt section getting softer. Either way, I believe that by making the Aldila shaft shorter in length, the initial launch improved tremendously, from directional launch to vertical launch.


WHERE TO GO FROM HERE



Overall, the experiment has piqued my interest in going to a shorter shaft. I would trade a possible 1 mph or less clubhead speed for better launch conditions and more accuracy and consistency. However, I do not think using the same UST Mamiya Shaft Model is the answer.

While the lead tape on the hosel is a bit gaudy looking, I would also worry about the lead tape coming loose and having to deal with that in the course of a round. And according to Wishon, you start to see a difference in face angle measurements once you add 11 grams to the hosel. Here I would be adding more like 12-13 grams.

My solution is to find a similar shaft model, but at a heavier weight. The next best solution seems to be the UST Mamiya ProForce VTS Red 7x shaft. This shaft is practically the same bend profile according to UST as the Silver 6x model. But, it weighs 76 grams, which is about 9-10 grams heavier than the Aldila RIP Beta shaft. I have the Red 7x in my 3-wood. Thus, I hope to put the Red 7x in the 10° head, get a little higher launch angle, be better directionally and have more consistency and only have to add 3-4 grams of lead tape to the hosel.


SYNOPSIS

So here is the rundown for going to a shorter driver shaft:

1. Affects the weight and MOI of the driver.

2. If you match MOI to a longer driver, the longer driver will have a lighter static weight

3. Hopefully the shorter shaft will produce better launch conditions to improve accuracy and consistency

4. The trick is to figure out if the increased accuracy and consistency will outweigh any possible lost in clubhead speed.

5. You may have to go to a heavier model shaft with the same bend profile in order to play with driver with a shorter length shaft.




3JACK