Unlocking the Keys to Golf Shaft Design

July 9, 2015 10:25 pm Published by Leave your thoughts Choosing Xcaliber Golf Shafts

Most golfers and club manufacturers are well aware of terms like stiffness, butt frequency, torque, weight, balance point, etc.

The XCaliber Difference

The problem with defining shafts by any of these singular properties is that they do not address how these mechanical properties are distributed along the length of the shaft. And it is this distribution of properties that gives each shaft its performance attributes (launch, spin, etc.), and almost of equal importance its “feel” during the swing and at impact.

ALL XCaliber shafts have been designed paying STRICT attention to the distribution of all mechanical properties. I started this approach while at Grafalloy in the mid-90s and have been refining it ever since.

Standards of Measurement

Let’s talk about stiffness requirements.

FACT: There are NO standards of measurement in the golf industry – for instance, an ASTM (American Society for Testing and Materials) protocol has not been established. Every shaft and club company measures their product any way they desire (often by what makes sense from a marketing standpoint).

With that in mind, it should be easy to understand that Company A’s S-flex could be Company B’s R- or even their X-flex. No standardization at all.

To further complicate matters, most shafts are called certain flexes because in testing the tip end deflects a certain amount of distance (displacement) or oscillates so many times (frequency) when being secured from the butt end with a weight applied somewhere along the tip end.

A Breakthrough in Design

In the ‘90s a wonderful engineer named Dr. Citra Ie and I started testing how stiffness was distributed along the length of a shaft using a standard mechanical engineering beam theory test protocol. This methodology resulted in an EI Curve – an Energy Inertia measurement which accurately measures stiffness at any point desired on a beam (golf shaft) and shows graphically how stiffness is distributed.

Dr. Citra then developed a computer-modeling program that took my designs and accurately predicted EI along with ALL the mechanical properties of each shaft (weight, wall thickness, torque, etc.).

This was a break-through in shaft design!

We’d unlocked the key to understanding the performance of a shaft/club system but especially how to improve that performance! This test later morphed into a simpler method which produced a measurement system called zone stiffness frequencies.

The High Performance of XCaliber Shafts

So my design approach for the XCalibers is pretty simple: design golf shafts using a thorough understanding of the distribution of all its mechanical properties; use extensive player testing with golfers of ALL abilities, noting objective results (launch and spin) and subjective feedback (feel); modify the designs to accurately optimize performance both objectively and subjectively; and never be satisfied until the original goal is met – create the highest performing shafts in the world, period.

ONLY THEN do I put the name XCALIBER on that shaft.


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This post was written by Robin Arthur