Some musings on flexible shafts

Lag is often referring to maintaining the flex of the shaft through impact. Coming across an old file I thought it interesting to post it once more, the subject matter being flexing of shafts. It is really not meant to be serious but rather more for fun and for a better understanding of flex.

Sounds like the conclusion would be consistent with what most good players would experience.

This being the trade off between distance and accuracy.

There is no doubt I can hit loose shafts farther… but also no doubt they are not going to fly as straight.

I get some freaky long shots from R flex shafts particularly in the short irons, and I tend to hit R flex mid to long irons very low, long irons particularly. Overall I can’t stand soft flex shafts due to the lack of ownership of the head, but a little flex in the driver can be fun if you want to hit it far- not very reliable though.

Centrifugal shaft bending

There is a common believe that you load a shaft at the top and that it releases this potential energy by kicking forward at impact. Many have likely seen the shaft behavior with the butt end clamped to a solid support. Indeed it than behaves very much like a spring. Not so in a golf swing.

Once the hands are on the grip this dramatically changes the behavior of the shaft. Too much damping and the shaft can’t oscillate. It lost its spring like behavior due to the large damping by the soft biomechanical tissue of the hands.

Hence when someone loads the shaft from the top with a vigorous torque, and subsequently reduces this torque, the potential energy is dissipated in the hand club interface. Later on in the down swing there is a forward bending of the shaft due to a centrifugal torque.

Just for fun I used my math model to also demonstrate the centrifugal torque for our very, very flexible shaft. This centrifugal torque comes about due to the centrifugal force acting through the center-of-mass of the clubhead, having a small offset from the shaft.

I hit weak shafts shorter. Much shorter. I built a driver once with a whippy shaft. It was by accident. I had got the wrong flex due to a factory error. It probably was somewhere in the region of “senior flex”. It was so easy and effortless to hit. Almost like hitting a wedge. But when I put some effort in, it didn’t pay off in increased distance as it usually does.

It all depends on the shaft loading profile of the player. It can vary. True Temper had some papers out that addressed this a few years ago, but I believe they thopse papers are gone. From memory: The most usual profile is to load the shaft twice: During transition and towards impact. The transition loading can be very strong and it will unload way before impact. Then you have those who only loads during transition. I believe the pure TGM swinger will do that. In which case a whippy shaft will effectively work as a more acute accumulator #2 angle in the early down swing. Which is good for distance I guess. Then there are players who increases the load gradually towards impact. I believe I’m in that category. I push really hard on the shaft late and if it’s a whippy driver I have in my hand the shaft only flexes. The clubhead doesn’t speed up. If I go for a wide arch with far less driveloading late in the stroke I guess the shaft flex has less influence on my distance.

I have been using Harrison shafts for years. They used to say that the shaft that is right for you is the one that recovers excactly at impact. Not sooner and not later. That made sense to me then and still does.

There is still the common believe that one can load the shaft at transition. This implies that the shaft is considered to be acting like a spring in the down swing and unloading its potential energy through impact. This is a basic misconception.

Some even go further and claim the shaft to be the engine of the golf swing therefore even suggesting that somehow it generates power in the golf swing. The function of the shaft basically is to connect the clubhead to the golfer. Only the golfer is generating power, the shaft is a passive device.

The shaft is light and has some flex, sideways and torsional. The aim of club fitting basically is to take the specific torque time history of the golfer and match it with the bending and rotational stiffness of a shaft, such that there is a square contact of clubhead with the ball at impact.

There is basically initially possibly some bending at transition but released quickly there after. When speed increases further on in the down swing centrifugal force starts to play a role in two distinct ways - centrifugal stiffening and centrifugal bending.

Lag, what is your conception about shafts ? Could you imagine paying with a shaft having no flex whatsoever, hence infinitely stiff ? What is the role of feel, versus real ? Is the shaft merely a connection or does it play a more important role ?

Perhaps different protocols may address some of the loading issues you raise Mandrin.

I’m thinking that a pole vaulter wouldn’t get much off the ground if the pole was very stiff…maybe the pole is matched to their body mass and acceleration to determine amount of flex required to elevate a given height. Wouldn’t know though as us rats don’t get much off the ground…we do our work underground. :slight_smile: RR

Range Rat,

Very different situations. A pole vaulter transforms kinetic energy of motion into potential energy first, loading and bending the pole, and then subsequently utilizes the generated potential energy, i.e., the unbending of the shaft, to catapult himself high into the air.

Hence in pole vaulting basically horizontal motion energy is used to compress a ‘spring’. Subsequently the unloading of the ‘spring’ produces vertical motion. Hence there is basically a conversion from horizontal motion into vertical motion with the potential energy of flexing pole as intermediate conversion step.

The flexibility of the pole plays a very important role. It is a classic example of transformation of kinetic energy of motion into potential energy. I am assuming that the difficult part for the athlete is to learn to maximize this transformation process.

Some can hit a golf ball using a cord instead of a shaft. I don’t know if the same can be said for a pole vaulter. :wink: In golf there is almost only generation of motion, kinetic energy, using muscles. The more the better for greater clubhead speed.

In golf there are two main concerns – clubhead speed and clubhead path/alignment at impact. The matching of a shaft to a particular golfer is likely mostly a matter of obtaining optimum impact conditions and not to maximize clubhead speed.

Totally agree, with the additional aims of shaft fitting being to:

  • present the optimal dynamic loft at impact for the delivered clubhead velocity for maximum distance
  • have the club feel balanced throughout the swing

Will a much stiffer shaft eliminate these varibles to an extent and thus put more control in the golfer???


I am a bit surprised with the lack of response. Usually posts which deal with clubs attract comments. :wink:
Does a certain amount of flexibility augment feedback sensations for the pro type player ?
Or is a a very stiff shaft the theoretical ideal to strive for in high performance golf ?

For what it’s worth:

Soft shafts for touch/feel:
If I recall correctly, Jack Nicklaus at one point said that he eventually gravitated to softer shafts in his wedge(s) because he felt they helped promote his touch for the short game.

Stiff shaft experiment on persimmon for control:
I hope to understand through actually using extra stiff shafts what is supposedly so wrong about them for a weak hitter, but I just might gain extra control with a little lost distance if any. What I would look for is the very stiffest light metal shaft I can find and put a 2-wood persimmon head on it and drop the lie down to 49 or 50 degrees. Even if it doesn’t work, the contrast of the extra stiff shaft might provide a new feedback source that promotes more touch with the regular or softer stiff shafts that I have now on my persimmon woods.

I would tend to agree with Nicklaus about leaning toward looser shafts in the short irons.

The step pattern (when shafts had steps) typically would come stock in 1/2 inch increments, but I would not be opposed to trying a set with much tighter increments, so that the shorter irons would not get as stiff. The stiffness would develop more from shaft length becoming shorter, than the step pattern.

I might try to set up a set of irons like this soon.

I like my driver, fairway woods and long irons really stiff.

Like many things, the stock gradation was someone’s opinion way back when… but it might not be ideal. I don’t see why
the gradation couldn’t be a custom element of choice particularly for better players.