The ABC’s of Shaft Flex: No Longer Your Normal ARS’s

Shaftology 101 states there are 5 basic shaft flexes (L, A, R, S and X).  For those new to golf, here is what the letters stand for in the order from the most flexible to the stiffest. The L stands for ladies, A for amateur or senior flex today, R is regular, S is stiff and finally X is extra stiff. These have pretty much stood the test of time since shafts first received flex designations, but that is not the case anymore.  Here is a primer to get you up to speed with all the new designations you may encounter.

Not to be confused with sub-flexes for True Temper’s Gold series (R200), the R2 designation is mostly found in high end Japanese manufacturers such as Fujikura, Graphite Design and UST Mamiya’s Attas division.  The R2 is the equivalent of the modern day A-flex.  Instead of calling it amateur or senior flex which is ability or age related, the R2 is simply a softer shaft than a standard regular flex for those with reduced swing speeds.

The R3 nomenclature was also derived from the Japanese manufactures and would be the modern day equivalent of L or ladies flex.  The name R3 takes out the sex of the individual in the fitting equation and instead relates it the player’s swing speed much the same way that ladies grips are now referred to as undersized. The R3 flex is the gender neutral term for those with the lowest swing speeds.

This flex designation can be confusing because some may look at the SR as being short for senior flex. Or others may think it could be a combination R and S flex model depending how it is cut.  It is neither.  If it were a combination flex, most manufacturers would have it look like R&S or R/S.  The SR actually stands for strong regular.  Another way to put it, it is in-between a traditional R and S flex as a single or discrete flex.

Unless you see characters like / or & in-between the S and X, then it is not a combination flex shaft like some of the FST steel iron shafts.  Rather this is a discrete flex that is in-between standard stiff and extra stiff.

The “T” as we will show in a couple of examples refers to Tour flex.  So the TS are short for Tour Stiff.  This is a flex that is stiffer than traditional S flex but softer than X flex within the same family of shafts.  TS may be equivalent or a cross-over to the SX designation.

Ditto here, it indicates Tour extra stiff and is stiffer than a traditional X flex.

The double X – yes, there is such a category for those with very high swing speeds in which standard X is just not stiff enough.  XX may be equivalent or a cross-over to the TX designation.

2X, 3X
2X is the same as the XX, but just another way to see it.  You might find these specialty shafts for long drive competitors.  There are also shafts designated as 3X or essentially a XXX flex which would be the stiffest shafts of all.


  1. paul oppenheim says:

    so from above, the old R is gone (?), and I guess the SR would be the new R – is that right?

  2. James says:

    I like this naming system much better than the current system. I can’t tell you how many times I have needed to fit someone who is their 40’s into an “A” flex shaft, but that golfer doesn’t consider themselves either an amateur (they have been playing for many years) nor a senior. If I tell that person I’m fitting them with “Amateur” or “senior” flex, he is likely to argue the fact that they are neither of those and possibly even get offended. If I tell that person they fit into an R2 flex, which is just a little bit softer than a traditional Regular flex, they would be fine with that.

    I also like how R3 replaces ladies, because there have been several instances where I have needed to fit a man with a ladies shaft, but you can’t really tell them that. I just tell them that the “L” stands for “Light” flex, and that it’s 2 steps down from a regular flex and then they are okay with it.

  3. Paul says:

    I am curious, as to why Hireko doesn’t offer shaft spine aligning (or PUReing, etc) as an option on assembled clubs.


  4. Jeff Summitt says:


    R flex will remain a mainstay. Graphite Design has a few shafts with the SR designation that many don’t what it is. I just wanted wanted to alert fellow golfers what it is and avoid purchasing a flex they didn’t think it was or direct a player into a flex they didn’t know existed.

  5. Paul Kelly says:

    Hi Jeff: It is about time that the flex for shafts has been broken down simply because of the technology that is available today and we have been using the 5 basic groups for years.
    However there are still no Standards between different manufactures and a R shaft is not necessarily the same as a R shaft from another manufacturer.

  6. Jeff Summitt says:


    PUREing requires a licensing agreement with SST Pure to offer it as a service. We have not had enough requests from customers to pursue it. Spining is another issue. Many independent clubmaking shops that we sell to do that as a service. Plus we aren’t set up to do it and still get all the orders out in a timely fashion.

  7. Jeff Summitt says:

    Paul Kelly:

    While there are no standards for flex, it is much better than in years past. Plus, standardization will never work unless you are comparing shafts of like weights. A 40g shaft and a 70g graphite wood shaft or a 125g and 90g steel shouldn’t be the exact same flex (frequency).

  8. Bob Jess says:

    Spining a golf shaft is a very simple procedure that can be done in less than one minute by anyone.
    I never fit a head without first spining the shaft, the benefit is far to great to miss out on.
    So i am very suprised Hireko does not offer this option.

  9. James says:

    So basically, the different flexes would be in the following order with the new naming system (from softest to stiffest, obviously):

    R2, R2, R, SR, S, TS or SX, X, XX, XXX, etc.

  10. Jeff Summitt says:


    Almost, change the first R2 to R3 (or L). You will still see L and A flexes listed by almost all US manufacturers for the time being because of tradition.

  11. James says:

    Oops, I obviously meant to put R3 first instead of R2 twice.

  12. fred ender says:

    Due to some vendor misinformation, I had to put wood shafts into iron heads by shimming. That’s all fine but–my assumption was that untipped shafts, given the same manufacturer and same flex, the wood shafts would be softer, but they do not seem to play that way.

  13. I just finished profiling 20 L-flex shafts from different club makers. None was the same, particularly at the mid point and the tip. The only similarity was that lighter shafts, when measured fro
    The butt, we’re more flexible than heavier shafts. The new designations are good marketing, but they are just a starting point for exact fitting.

  14. Joe B says:

    Any clarification of shafts is a plus, but tell me this new system is not still left up to each manufacturer to classify their shafts, and that it will be industry standards.

  15. Jeff Summitt says:

    Joe B:

    This may be written on my headstone someday, but the only standard in the golf industry is there are no standards.

  16. Justin says:

    Joe B: Tom Wishon was a member of a group headed by the American Society for Testing and Materials (ASTM) to essentially standardize golf equipment. They tried for three years, with the equipment makers acting uncooperative, before giving up (from Wishon’s “The NEW Search for the Perfect Golf Club”, p. 123-124). So, don’t plan on it happening any time soon.

    Paul: Spining a golf shaft is one of the last things to worry about; the length, face angle, grip size, etc., etc., not to mention the golfer’s swing, should all be addressed before spining is even an option.

  17. Scatter says:

    I know the frustration Tom Wishon must have felt. The following may help Tom and other interested in standardizing golf shafts. The first thing is that all ASTM committees are usually comprised of “Users” and “Producers” type members. In order for a committee to be “Certified” there shall be a majority of user type members compared to the producers. Committee certification is a requirement for any published standard to be automatically accepted by other industrial standard societies or government agencies (SAE, ASME,Department of Commerce, etc.). Each independent user type member gets one vote each,limited to one voting member per company or agency. Each producer “company” has one and only one vote for the producer company regardless of how many representatives they may have on the committee. “Get the Gist?” When a standard is up for an approval vote; any and all objections to the standard must be a “written objection.”. These can either be accepted (by a committee vote) or rejected (by a committee vote). Objections need sound technical justification and can have nothing to due with economic ramifications. If the objections are rejected they are “found to be unpersuasive”, documented and the standard moves on to publication.

    Once published, there is another venue that maybe should be explored. I believe that ASTM, through the Department of Commerce should establish an ISO Tag within ASTM. The Department of Commerce should get the United States defined as having the authoring authority for an International Standard which now transcends just a US recognized standard.

    Other interest parties may include the USGA, PGA and other international golfing bodies.

    I’d be glad to clarify or answer any questions you or others may have.

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