Soft Stepping and Hard Stepping Iron Shaft Sets

Adjusting Shaft Stiffness with Soft and Hard Stepping

By Russ Ryden, A Golf Digest America’s 100 Best Clubfitter
Fit2Score, Dallas Fort Worth, Texas

Soft stepping is the term used to indicate changing flex of a taper tip shaft by adjusting the stiffness of a set of irons by putting the lower numbered iron shaft throughout the set.  For example, the 8 iron shaft is put in the 9 iron, the 7 iron shaft in the 8 iron and so on through the set. Hard stepping is just the opposite, putting the 9 iron shaft in the 8 iron, the 8 iron shaft in the 7 iron.  This practice applies to sets of shafts that are produced with specific designs and lengths for each iron in the set.

KBS_Tour_ETT_XP95_EiWhen we look at shaft sets we see two design philosophies. The consistent EI weight/flex designs and the True Temper Dynamics design . This is best explained by looking at some EI stiffness charts.The first chart shows the KBS Tour X, S and R flex shafts. The profiles and consistent, simply getting overall stiffer as they get heavier. Most True Temper shafts have different profiles. The tips are not only softer, but longer up the shaft in the R flex model. The tips get both progressively stiffer and shorter in the S and X flex models. In a shaft like the KBS, the difference between and R and an S is simply a little heavier and a little stiffer overall. In the Dynamics design, the profile of the S is significantly different from the R.

Now lets take a look at what happens when these different designs are hard or soft stepped to change stiffness. And, compare hard and soft stepping to changing flex.

KBS_Tour_SteppedHere again is the KBS Tour. Soft stepping, putting the 5 iron shaft in the 6 iron, moves the flex of the shaft about 1/3 of the way toward the R flex shaft.  A double soft step, 4 iron in the 6 iron will move the flex another 1/3 toward the R flex. The weight of the shaft changes very little with stepping. The 120 gram S flex is still 120 grams while having a stiffness similar to the 110 gram R flex model.

TT_XP105_SteppedNow lets look at the same EI chart of the True Temper XP105. We see the same change of profile from hard or soft stepping. A slight change of overall stiffness of the shaft. However, when we look at the R flex shaft we see that it has a significantly different Ei bend profile.

Fitting the True Temper Dynamic Designs

From a club fitting perspective EI Bend Profiles give us a new understanding of fitting the True Temper designs. Adjustment made with hard and soft stepping have a small effect on stiffness and flighting. Adjustment made with flex changes have a significant effect on both stiffness and flighting. To get a precision fitting it is important to work with a fitter that offers the options to hard and soft step the different flex offerings.

  • jim.k

    What about hard stepping the R in the kbs. Is it stiffer than a soft stepped stiff.

    • DevotedGolfer

      Generally hard and soft stepping moves the flex about one third of the stiffness difference between the flexes. I checked this extensively with KBS. KBS offers mid flex in some models, R+ and S+. These are half the weigh increment and are truly half the weight difference. With hard and soft stepping you get a stiffness change without a weight change. And that may be an important fitting consideration for your swing dynamics.
      So, the answer to you question no, a hard stepped R is 1/3 softer than a soft stepped S.

  • BEC

    I was recently fit with Cobra F6 heads and Nippon NS 1050GH shafts. I’m about 6 feet tall, but with long arms. I was fitted to get shafts that are 0.5″ shorter than standard. Should I install shafts -1 club to adjust length or should I soft step them (which as am reading is taking the shaft and cutting them) to length? From my fitting, i probably could be a little bit softer than stiff, as long as the torque doesn’t change too much.

    To go along with this same thought, I was hitting the Steelhead XR iron heads and i’m wondering if i put those with the 1050GH shafts if I could expect the same feel, or if I’d need to get totally refitted again because of the weighting of this different head.

    Finally, i think you’ve talked about this before on other threads, but sometimes i see Nippon shafts listed as 1050GH, and sometimes as 1100… are they very nearly the same thing?

    • At 6′ tall, I cannot imagine fitting you a half inch short. I have never had that experience. My first advice is that you get a second opinion on that recommendation from an experienced golf swing coach.

      I cannot tell you how a shaft might feel, that is entirely personal. My best recommendation is that you buy a few matched 6 iron heads, used is fine, and try out some of the shaft combinations you are considering before you build a complete set you may not like. Have some fun with this project. It is amazing what you will learn along the way. I do this with many of the golf pros I work with. They truly enjoy learning what different shafts ‘feel’ like.

      If you need some heads, I have some that accumulated over the years that have been used as fitters and for comparison tests. Contact me through if you are interested.

  • Moe

    I recently bought a set of Mizuno MP-5 and was fitted with Dynamic Gold AMT S300 shafts. My clubhead speeds are 90 – 83 mph for 3 to PW. I find these irons to be slightly too stiff (feels like the shaft isn’t loading enough, shots go a little right of target), especially the shorter irons. Will soft stepping help or should I replace with Regular shafts ie. DG AMT R300 or keep to stiff but go for a lighter weighted Stiff shafts like Nippon Modus3 Tour 105 S or KBS Tour-V S. Prefer a low to mid flight.