Regular Vs Stiff Flex for Golf Irons – Everything You Need To Know


In golf there are a few things that people like to brag about around the club. How far they hit a driver, how high their swing speed is and what their handicap is to name a few. However, another that people use as a bragging point is the flex of their shaft.

This can get tiresome and it can mean that some golfers play a shaft that isn’t quite right for them, just so they can say they play this or that. Well today I want to go into this topic with a particular focus on iron shafts. What flex should you be using and why?

Let’s take the guesswork and ego out of this important topic and put some detail to the question. What kind of golfer benefits from a regular flex iron shaft and who would benefit from a stiff shaft? Why do they need what they need?

Read on to learn more about just how important the shaft in your irons are. If you thought that this was some bland metal or graphite part to a club that just provided length then you may be surprised. This one gets interesting.

“You’ll never be able to hit this”

As a young junior golfer spending my summers on the golf course, I got to know the pros and assistant pros at my club well. One day, the cockiest of the assistants was bragging about his new irons and how stiff the flex in the shafts were. Being a little cocky myself at 14, I asked him for a shot.

He handed me this Mizuno blade and told me that it was way too stiff for me, I’d never be able to hit it. I swung the club as hard as I could on the first tee to prove him wrong. He was right, that shaft barely moved during my puny junior swing, it was way too stiff, lesson learned.

The basics

What are the basic differences between a regular and stiff flex iron shaft?

The main difference is that a stiff shaft is harder to bend than a regular shaft. This is usually created by adding more material to make the shaft up which can often also make them slightly heavier. The more force you create in your golf swing (higher swing speed) the stiffer you will want your shaft.

Iron shaftsb

When it comes to iron shafts, the options of what you can play is growing but not as fast as it is in graphite shafts. You have three main choices when it comes to your irons. You have the classic steel shaft, the graphite shaft or the innovative SteelFibre (a graphite shaft surrounded by a very thin layer of steel fibre).

Within the steel category there, you can have a stepped shaft (the most common one you are used to seeing) and rifle shaft which has no steps on it at all. You then have the option of flex to add another layer of complication on to all of these choices.

Who should use stiff flex irons?

The starting point for this is swing speed, if you swing your driver between 90-105 mph then you will probably need a stiff shaft. This will benefit you by delivering great control of your club during your swing and stop you spraying it everywhere. Also taller players using longer clubs require stiffer shafts as they have a longer lever with the clubs.

Interestingly, most wedges on the market have a stiff shaft to maximise control of these more attacking shots. If you’ve ever seen that the shaft on your wedge states that it is “wedge flex” it is actually stiff and they just don’t want to spook you if you’re a regular flex golfer.

Who should use regular flex irons?

Regular shafts come in three grades, ladies flex for the shortest hitters (terrible name really), seniors flex for those who hit it a little longer (equally terrible name) and regular for those who hit it furthest. A driver swing speed between 85-90 mph will be the kind of golfer looking for a regular flex.

A regular shaft will help maximise the distance you can generate from your golf swing. This is when you need to be honest with yourself and if you need more help then accept it. Even if that means playing a senior flex in your forties, if it will help you then go for it.

Quick reference guide

You can see below a quick guide to swing speed and shaft flex. You will notice the mention of tempo. The way to think of this is how much time your swing takes to perform.

So a smooth swing creates less of a load on the club and slow requires less stiffness than an equivalent speed higher tempo swing.

Other flex options

We’ve looked at the other options that exist for regular flex but there is a split in stiff shafts too. Elite golfers can create swing speeds that far exceed what is on the chart above and so they require stiffer shafts. On top of stiff you also have extra-stiff which would be for swing speeds over 105mph.

When some tour golfers swing the driver they can generate 115mph and more, some even exceed 120mph! For these players only tour extra-stiff will be stable enough to handle these speeds. It is seriously impressive that people can swing a club that hard and that accurately.

What do the numbers of shaft flex mean?

Some brands use a numbering system instead of statements around what flex a shaft is. Starting at 5.0, the stiffness goes up in steps of 0.5 up to 7.0 which is tour x-flex. These are rifle shafts, they don’t have the usual steps that you expect to see on steel iron shafts.

The company say that the steps in the shaft reduce the power that is transferred through the shaft and into the club. The average golfer may not notice this difference but Precision Made, the company that manufacture the products say it exists.

How will flex affect distance, trajectory and accuracy?

Using the wrong flex can really affect all three of the above so it is important that you get it right. If you have a shaft that flexes too much you are likely to hit high hooks as the club can’t handle your speed. If you have a shaft that is too stiff for you, you will hit low slices as you can’t move the club fast enough.

Both issues will affect distance because you are using an inefficient system and you will find it very difficult to be accurate. A skilled custom fitting technician can help you make the right choice and build your clubs correctly.

Could I use a stiff driver and fairway woods but regular irons?

Yes, you certainly could and there are a couple of reasons why this could be the right set-up. For starters, on a purely engineering level, the driver and fairway woods are longer clubs so you will swing them faster as they are longer levers. This means that they will often require stiffer shafts.

Also, they will be graphite shafts so you may want a stiffer graphite shaft than your steel iron shafts. Finally, if you swing speed is just in that stiff shaft bracket for your driver, you may just need regular shafts for your irons, it can be as easy as that.

Does shaft weight affect flex?

Indirectly, yes it does and it is very important for other reasons too. According to MyGolfSpy, weight and torque may be more important than shaft flex when it comes to the performance of your clubs. If you think about it, the heavier a club is, the harder it will be to swing it fast and therefore the more flex you will need.

Also, according to the small study done by MyGolfSpy (link above) the weight of the club helped keep players on plane during their swing so it was fundamental to swing performance. Weight is something that very few of us actually think about, we are obsessed with flex and there really is more to it than that.

Stiff or regular for beginners?

No matter how long you have been playing the game, you need to match your shaft flex to your swing speed. There is no reason that a beginner can’t have a fast swing, maybe she played hockey at a high level and now wants to play golf. She will have the making of a swing from her hockey days.

I am of the firm belief that even beginners could benefit from having an expert pick clubs for them. Too many just take whatever is available, I very much understand this, however, getting the right clubs for your swing will make it easier faster.

Graphite or steel for your irons?

This depends on you fast you swing the club, I believe that people who swing the club fast (players who use stiff shafts and stiffer) should use steel in their irons. However, players on the regular side of the spectrum can gain a lot of club head speed by using graphite. You see many tour players coming to the end of their careers switching to graphite irons.

The SteelFibre that I mentioned at the beginning is becoming very popular too. This is a best of both worlds sort of deal that helps people gain speed due to the incredible lightness of the product. They are expensive but if you have it and want it then go for it.


Senior vs regular flex: what’s the difference?

This is like a half step on the flex spectrum. For those who find regular just a little bit too stiff and are looking for a little more help, senior flex is the one for you. They tend to be a little lighter too which will help you create more speed.

Ladies vs regular flex: what’s the difference?

This is a larger jump than what’s above, it is more like the difference between regular and stiff shafts. Ladies flex is the shaft that bends the most during a swing as ladies tend to have the slowest swings. I think this name needs to change, however, if you don’t create much speed then this is the shaft for you.

Is firm flex the same as stiff flex?

You used to see firm flex on more clubs, this is like a half step up from regular. It is hallway between regular and firm and will suit many golfers who can swing a driver at around 100mph. It is one of those niche flexes.

How can I tell my club head speed?

Launch monitors will be able to tell you very quickly how fast you swing a club. Book a session with your local pro or technician at the local driving range and you can find out your speeds. Just try to swing naturally, it’s not a competition.

Do any tour pros use regular shafts?

Tour pros change equipment far more frequently than we mortals but yes, some do use regular shafts at times. One thing to bear in mind here though is that there is no industry standard on stiffness so one brand’s regular can be another brand’s stiff.

How can I tell the flex of my shafts?

There should be a sticker that indicates it near the grip and it should have a letter on it, R for regular, S for stiff etc. That’s the easiest way but if the sticker isn’t there then you can take it to a pro who can do some investigatory work for you. Another option is to find a friend with the same shafts and line them up beside each other, if they have steps in the same place then it is the same flex as theirs, if not you need to find another friend.


This article shouldn’t make you worry about getting the wrong flex, it is quite easy and with the right professional help it is even easier. It is important that you get this right though because the shaft is like the engine room of your golf club and it can really help maximise your swing.

As you can see, there are so many options for the flex of your shaft that there will be something out there for your swing. 80% of golfers fit into a regular or stiff shaft so you are probably going to be fitted with one of them.

If you’re not sure that you have the right flex shafts in your irons then book yourself some time with a club fitter. Talk to them about your golf game and take a few swings on the launch monitor. Go get your equipment checked and enjoy finding the perfect new clubs.