TBAR Part 2 – The Art of Golf Shaft Measurement

TBAR- The Art of Golf Shaft Measurement Part 2

TBAR™ – The Art of Golf Shaft Measurement Part 2

By Carter Penley

Through the years there has been a quest by many to define a golf shafts performance or the ability to fit a player by some simple magic black or white number or method. Some like to know how fast a player swings their club, or prefer a torque number, or a flex, or a shaft weight, or clubs swing weight, or a club length, or a shaft color, or… The fact of the matter is that there are many variables that contribute to fitting a player, some of which are more important than others: It is all a sea of grey. While no single measurement can define the total “performance aspect” of a golf shaft, I do believe there is a way to simplify and reduce the number of measurement variables.

After close to thirty years of designing carbon fiber (graphite) tubes parallel and tapered tubes, specifically golf shafts, I have come upon some interesting correlations in golf shaft measurement that can yield a more accurate method to define the “performance aspects” of a golf shaft that technically affords the club maker or teaching professional the advantage to better fit a player at most any level of play.

Historically golf shafts have been measured and the data has been presented in four specific areas.

They are:

  3. FLEX

For design and manufacturing purposes there are many more measurements required, but for current discussion I will focus on these four, which are most commonly published and used.


TORQUE stands alone and is one measurement most commonly debated throughout the golf industry, although used frequently when fitting. Yet it is probably among one of the most inaccurate golf shaft measurements because there is no standard in the industry by which to compare the data. Quite frankly, not many club makers can measure for specific torque in a particular manufactures product and therefore most club makers rely on the golf shaft manufacturer’s torque number, accurate or inaccurate as it may be. (See ‘Torque article, 1997 by C. Penley)


WEIGHT is another stand alone measurement and agreed to by most all is the most accurate measurement (one gram is one gram), although again there is not a standard. Weight is specified as ‘X grams +/- X’ grams, but some manufactures include paint some with out paint, sometimes weight at full length or at some unknown cut to club length, also some shaft lengths can very from model to model and manufacturer to manufacture.

This is because club manufacturers measure club length differently; some measure club length from the club heel, the center of the sole plate and if it is a bore-thru not to mention some club manufactures have a specific club length different from their competitors.


FLEX is a measurement that has somewhat of a standard due to the fact that this measurement is easy to determine statically (flexboard using a weight and a limit shaft), and does not require a costly piece of equipment. On the other hand a dynamic measurement as performed on a frequency machine and does promote somewhat of a standard because of the wide acceptance of the old Brunswick frequency charts by many club makers (not withstanding inter-laminar opposing shear deformations). But even this form of dynamic measurement can be easily skewed due to the following:

  1. At what position at the shaft butt do you clamp the shaft?
  2. How much clamp pressure is used to clamp the shaft?
  3. Do you use an actual club head and whose, blind bore or bore-thru?
  4. Do you use a bob weight? Weight and hosel depth of bob weight?
  5. Where is the bob weights center of mass in reference to the shaft tip?
  6. Manufacturer and type of grip?

Again with no standard method, a comparable measurement is difficult to achieve.

Even with all the equipment, charts and graphs that are available to determine the flex range much of this data was developed as much as 20-70 years ago with steel shafts, and does not accurately reflect the standards required for today’s modern composite golf shaft.


Last but not least. Most people have little or no idea of how this measurement is made much less its accuracy or its usefulness. This undoubtedly is the least understood measurement of all. I can tell you from experience that this measurement is probably the least useful for the fitting of a player. (See Part 1 ‘TBARtm vs. Kick (Bend) Point‘)

It is these last two measurements that I have a problem, specifically the latter.

Flex and kick point are measured and recorded as two separate measurements and I am of the opinion that these two measurements are closely related and should be combined to develop a new measurement. Standing alone they can be more of a hindrance than help when fitting a player. Combined they are a powerful fitting tool!

At Penley we have solved this problem and developed a new measuring system and related manufacturing design and process, called ‘Tip to Butt Aspect Ratio‘ (TBAR™) algorithm that we believe will help the golf industry change the way it has measured and fit players for the past 30 or more years. We believe the relationship between the butt section and tip section of the golf shaft is and should be a single measurement and is most important to the fitting of a player with a club (Amateur, PGA or Long drive) that enhances and improves their overall skills.

Read more about TBAR™ with Measurement and Method Part 3

Copyright © 2002, 2015 Carter Penley. All Rights Reserved
(all theories and analysis are still pertinent)

More About TBAR

9 thoughts on “TBAR Part 2 – The Art of Golf Shaft Measurement

  1. Every thing your are talking about is the reason I profile shafts. It tells me what I need to know about play ability of a shaft. If you need copy of my BMT let me know and I will send you a copy.

  2. Hello Jonathan,
    We will be releasing the next Article about TBAR in the next couple of weeks. If you haven’t signed up for our newsletter yet or would like to be added to our list, please let me know or check back here in the next couple of weeks. Thank you!

  3. Hi Guys,
    I have struggled the last couple of years to find a driver shaft/head combination that felt good and performed good. I am 55 now and I used to hit the ball quite long most of my life . My swing speed was 126 when I was 30 and is now about 105. My problem is I have a quick transition and cannot find a driver that FEELS good and performs well. I am stocky build with a shorter swing and I hit ALL my other clubs reasonably well except the driver so I was thinking of shortening the shaft- but then the characteristics change. I believe I need a shorter (44.5-44 inch) shaft to control but still have some kick to it for distance. Any ideas? I want a Penley shaft or even the whole driver.
    In the great white north Canada.

  4. Hello John and thank you for contacting us. Based on the information you gave us, I would recommend the ET2 shaft for you http://www.penleysports.com/products/penley-et2-shaft/
    For Flex – As our shafts tend to have a tighter tolerance than other manufacturers, for example- if you are currently playing an ‘X’ flex, we recommend going down a flex size such as the ‘S’ flex.
    We do not recommend trimming, but should you need to – Butt Trim Only.
    If you have any questions or need more assistance, please do not hesitate to call or email us- sales at penleysports.com
    Thank you again John!

  5. Thanks for the reply
    That is the shaft i want but im afraid of trimming it and it changes its characteristics. Would trimming it down to 44.5 make a big difference. Or do I go regular and trim it. The reason I ask is I hit my 3 wood very well but want the extra 20-30 yards the driver will give me and all my friends say play a shorter shaft. I played a persimmon Ben Hogan steel shaft when i was young and hit that 300++. Im confused.

  6. Hello again John,
    It looks like the ‘S’ flex will fit you well. The only other factors we don’t know in regards to how much you should trim is:
    What type of head are you using, and what kind of adaptor?
    Penley recommends before you trim the ET2, assemble the club head, adaptor (if using one) before deciding to trim.
    If you feel that you need to trim down the shaft – Butt Trim Only.

    If you would like us to put together the driver for you, we do have a special price for a custom club:
    if you have any other questions or need help please do not hesitate to email us – sales@penleysports.com or call us – 619.668.0043 –
    Thank you again John!

  7. Having you build the club is kind of what I was thinking but this Zone Flex has me a little befuddled. I feel when I buy a super stiff heavy (70-80 gram) driver shaft it is like lumber but I can feel the club throughout the swing but its hard to square up at impact. – I have tried a very light shaft and feel nothing at the top my swing so I transition too quickly and pull drives. So I am going for a feeling of where I can feel it loading and have some kick at the bottom- I had a Tour Design ad6, a Mitsubishi Diamana Blue board at one time and loved but I remember having a Penley Black and Yellow shaft many years ago that I loved. All were stiff as I found the quality of these shafts are high and x-stiff was too much.
    My thinking is a 9.5 (I tend to spin the ball too much) with a stiff ET2 at 45″. (Just not sure which Zone to choose) My friends all say my ball rockets but then
    floats and dies where theirs just kind of knuckles out there. My ball speed when tested was 158-162 on the driver so I should be getting better distance.
    Thanks for the help

  8. Hello John I went ahead and emailed you a couple more questions, but I think we can get you fixed up with the right driver for you- thanks!

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