Shafts 101 – Shaft Flex

Shaft Flex

Alright, everyone in your seats, Shafts 101 is now in session.  In our first class, we’ll be dealing with one of the most basic, but also most misunderstood, elements of shafts: flex.

What is Shaft Flex?

If you think this is a basic question, you’re wrong.  The top shaft manufacturers in the game can’t even agree on a simple definition!

Nippon defines shaft flex as “the amount the golf clubs’ shaft deflects or bends,” but True Temper says it’s “the resistance to bending.”  Mitsubishi Rayon (MRC) and Fujikura told us about how shaft flex is a guideline for connecting swing speed to a particular shaft.

Regardless of the semantics, we’re talking about the flexibility of the shaft.  A shaft that’s X-Stiff will be very rigid and hard to bend.  A shaft that’s Senior or A-Flex will be very loose and easy to bend.

Shaft Flex_0016

How is Shaft Flex Measured?

There are numerous ways to measure shaft flex.  The most common way is to clamp the butt end of the shaft, attach a weight to the tip, displace it, and measure the CPM (cycles per minute) or frequency that the shaft oscillates.  This can also be done in reverse – clamp the tip and weight and displace the butt.

Other manufacturers also use EI, flex boards, deflection boards, and constant loads.

Given that there’s not a standard way of measuring flex, you can correctly assume that there is no standard for labeling flex either.  What one manufacturer calls “stiff” might be “regular” to another.  This is why they universally emphasize the importance of fitting.

Shaft Flex_0022

Is Shaft Flex Constant?

Once you and your fitter have determined that you fit into a regular flex Diamana B Series shaft, you can assume that you’re an R-flex in all MRC shafts, right?  Wrong.

While they didn’t agree on much, every shaft manufacturer that we spoke to said that flex is only one part of the equation.  MRC noted that torque values will vary widely from model to model, and that has a big impact on performance.  Fujikura and Nippon both agreed that other factors need to be taken into consideration when fitting a shaft.

Rules of Thumb

You’ve probably started to notice a trend here: there are few, if any, industry standards and in person fitting is key.  But there have to be some basic rules of thumb, we can follow, right?  Here’s what the manufacturers told us:

Mitsubishi: Identify the correct shaft profile first, then fit weight and flex.

Fujikura: See a qualified fitter!

Nippon: As swing speed increases, shaft flex should be firmer.

True Temper: Play the most flexible shaft you can control.

So, in short, no, there aren’t any rules of thumb, or at least not any that the industry can agree on.


Does Shaft Flex Matter?

With all this disagreement about definitions, measurements, and rules of thumb, does shaft flex even matter?  Yes, very much.  The one thing that every manufacturer and fitter agreed on, besides the need to be fit in person, is that getting into the correct shaft flex is critical.

Club Champion’s Nick Sherburne laid out the benefits of playing the correct flex.

“The right flex can lead to better quality of contact, a more consistent shot pattern, and better distance and distance control.”

All the manufacturers concur.  Fujikura said the benefit of playing the right flex is, “Consistency!”  Mitsubishi told us it will “optimize a player’s performance.”  And Nippon said, “The correct shaft flex will optimize distance, spin, and dispersion control.”

So, if hitting longer, more consistent shots is important to you, playing the correct shaft flex needs to be a top priority.  Find a qualified fitter in your area – there are no shortcuts – and get your clubs matched to your swing.

Class dismissed.

Matt Saternus


  1. Gary McCormick

    So we have quotes from a bunch of shaft manufacturers telling us that flex is important, but nothing about how and why. Where in the swing does shaft flex make the most difference – in the acceleration of the downswing or during the milliseconds in which the club head is in contact with the ball?

    • Matt Saternus


      Shaft flex affects distance and accuracy, so clearly an effect is realized during impact.

      If you’re looking for player data, we have a Golf Myths Unplugged regarding shaft flex coming out in mid-October.


  2. I tried a callaway xr driver with a fujikara 565 shaft and really liked it; the price scares me; what does the evolution red 565 differ and is there another shaft which may be comparable; i am 70 shoot in the mid 80’s with a regular shaft hitting around 220-230 i noticed significant distance and accuracy with this driver and shaft

    • Matt Saternus


      The only way to find another combination that will provide more distance and accuracy is to work with a fitter.


  3. Do you discount for multiple variots purchases to Golf club repairer.

  4. I bought some fairway graphite clubs from warrior custom golf. The only print on the clubs is custom fit flex and low torque hi-modulus graphite. What does that mean, what is the flexibility ,stiff / regular / senor

    • Since there are no true industry standards on nomenclature Jeff, you’ll want to to direct that question to Warrior.

      – Meeks

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