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Golf Shaft EI Profile Software

I was introduced to the concept of shaft profiling, the measurement of the golf shaft at various points on the shaft, early in my education of club building. I started using frequency for measuring, a system still used by many club makers. As I learned more about shafts I discovered EI shaft measurement. There were no commercially available instruments for taking EI shaft measurements. Some shaft companies used laboratory strain testing equipment. Those were out of my budget as well as beyond the budget of many smaller shaft companies. I set out to make my own instrument and after many years and many designs, the instrument I now produce is accurate and easy to use. It is owned by many top club fitters around the world and several shaft companies.

A shaft measuring instrument requires software to collect and analyze the measurements. Below is an overview of the software I created. It now contains thousands of shaft measurements.

After many years of restricting the software to instrument owners I decided to make it generally available. It is available to golf professionals looking to refine their fitting and building practices. It provides the perspective of the golf shaft that is commonly used by golf shaft designers. The software has evolved from humble beginnings to an extensive tool for understanding the golf shaft. It continues to evolve as the database expands the view from iron shafts to iron shaft sets. If you are in the business of providing tour level golf club fittings, this is an essential tool for understanding the golf shaft.

Driver Shafts

Nothing gets more attention in the shaft business than the driver shaft. They are offered by companies large and small. The driver shaft software presents views of shaft models, individual shafts and close matches to a selected shaft. The driver software, written in Excel, starts with a page to compare up to 10 shafts with each other.

Driver Model Page

Seen here is the 2014 Diamana R shaft. It is selected in the top most pull down. All of the shafts in the model are charted. This lets you see if they are all a similar design, differing in stiffness or if different weights are actually different designs.
We will now examine each of these sections of this page.

Driver Model Selector

Ten pull down boxes let you select shafts from the database. They are arranged by manufacturer and model. The check boxes on the left let you use the shaft in the pull down list or default to the next shaft in the database. A single selection in the top box, created the page illustrated above.

Another option is to select individual shafts for comparsion. In this illustration, the 60g S flex model of the Diamana R, W and B models are selected.

Driver Model Selected EI

The Bend Signature is a unique chart. It displays the change in stiffness down the shaft from point to point. This unique view removes the stiffness and shows a clear image of the change of stiffness. When looking at all the shafts of the Diamana R, you can see they all have the same profile. They vary in weight and stiffness, but all have the same launch signature. Looking at the R, W and B shafts, the signatures are different. The Signature view is an essential tool for understanding the launch propensity of a shaft.

Driver Model Signature

The GJ profile shows torque measurements taken in 5" increments. Recently added are hoop deformation measurements also taken in 5" steps. Lower cost shafts, using 'thicker' carbon fibers may duplicate the bend profile of the premium shafts, but never the torque and hoop profiles. To achieve low torque, bias and hoop plies must be incorporated into the design. This requires higher cost 'thinner' carbon fiber sheets. This aspect of shafts cannot be overlooked in a comparsion of shafts.

Driver Model GJHoop

Recently added, with the help of my friend, Dave Tutelman, are deflection profiles. Deflections boards have been around since the early days of club building. The shaft is clamped at the butt and the tip and the total bend is measured. My point by point profiles are use to mathematically bend the shafts. Total bend is a classical way to rate shaft stiffness. The total bend numbers are presented in both graphic and table modes, creating a simple overall stiffness rating system.

Driver Model Deflection Modeling

The last element on this page is a table of important values of the shafts.

Driver Model Stats Table

Individual Driver Shaft Report

A full report of an individual shaft is available. This is for shaft company quality certifications. It is a great value added report for customers wanting validation of the shaft in their driver.

indivitual Driver Shaft Report

Shaft Matching

Knowing how shafts resemble one another one is the most valuable pieces of information a shaft profiling system offers the golf professional. With over a thousand driver shafts in the system, the matching software makes it easy to find shafts with similar bending profiles. With it, you can find a match to a shaft that works for a golfer. When outfitting a fitting system, you can avoid adding shafts that closely resemble ones you already have. Or, moving forward, when a shaft you like is nearing the end of its product life, you can find newer models that resemble it.
Most often, I use it to locate a shaft in my fitting system that resembles a shaft a golfer wants to try. The matching algorithm locates eight potential matches. The matches are filtered to include only shafts that have closely matched weight and torque. You can choose to see the shafts selected by the system individually or as a group.

Driver Match Overview

The matching page was cloned from the main page in the system. The elements described above are all shown for the shaft to be matched and the close matches found in the system. A brand selection check box is available to limit the brands in your search.

Driver Match Details

Hybrid, Iron and Wedge Shafts

Hybrid, Irons and Wedge shaft profiles are contained in a single file. The same format illustrated for Driver shafts is used in each of these sections. An additional feature is available in the Hybrid and Irons section, virtual trimming. Any of the Hybrid shafts or iron shaft can be virtually trimmed by the software to show the EI profile of a tipped shaft. The iron database is being slowing expanded with 5i and 7i factory trimmed shafts to enable a perspective on soft and hard stepping.

Iron EI and Trimming Illustration
Over the course of measuring countless sets of iron shafts I realized that iron shafts cannot be viewed by looking at a single shaft in the set. On many sets the bend profile of the 3 iron shaft was different than the wedge shaft. Some had the same bend signatures, but many incorporated progressive launch profiles. Some long iron shafts have a propensity to launch higher than the wedge shafts in the set. When the hybrid/long iron shafts were included in the same database as the six iron and the wedge it became possible to create a composite view of a set. This illustration compares two such sets, one with no progression and one with a mild progrssion. This bring a new dimension of understanding the the tour level fitter.
Iron Sets Illustration

The Fit2Score software detailed here is available for a subscription fee of $600US for the first year with an annual renewal fee of $300US. The software updates as new shafts and features are added.

If you are interested in a subscription to this software please contact me at

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Russ Ryden
Fit2Score Master Club Fitter
Call 817 247 3110

Golf Digest America's 100 Best Club Fitter 2011-2017
AGCP Master Fitter
AGCP 2009 Technology Award
Titleist Performance Institute Certified
GolfSmith Advanced Clubmaker
PCS "Class A" Clubmaker
Wishon Golf Technology MOI Certified
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