Golf Shaft Flex Guide NZ: How to Choose the Right Flex

Short Answer

Swing speed is a useful starting point for shaft flex, not the final answer. As a rough driver guide, Regular often comes into the conversation somewhere around 135 to 155 km/h, and Stiff usually enters the picture from about 155 to 170 km/h. Those are guides, not rules. If you're near the edge of a range, or you're buying used, the exact shaft model and how the club actually feels matter more than a few km/h either way.

Golf Shaft Flex Chart (km/h)

Here's a rough driver swing-speed chart to use as a starting point:

These are rough driver starting points only, not an industry standard. Different manufacturers and shaft families place these bands in slightly different places, so treat this as a way to narrow things down rather than a fixed rule.

If you already have a rough number in mind, browse our current used drivers or used iron sets.

What Shaft Flex Actually Means

Shaft flex describes how much a shaft bends during the swing and how it returns through impact. It's one part of how a club performs, alongside the head, the loft, and how you deliver the clubface.

A slice doesn't automatically mean the shaft is too stiff, and a hook doesn't automatically mean it's too soft. There's usually more going on in the swing itself, and we'll get into that further down.

Why Flex Labels Aren't Standardised

There's no universal rule that every shaft labelled Regular bends the same amount. One manufacturer's Regular can feel noticeably different from another's, and even two shaft families from the same manufacturer aren't guaranteed to match.

That's not really a flaw, it's just how the industry works. Flex is a relative label within a shaft range, not a fixed engineering standard across the whole market. Practically, this means the exact shaft model tells you more than knowing it's stamped R or S. If you're comparing two clubs and only one detail is available, the shaft model is the one worth chasing down.

Regular vs Stiff

If your driver swing speed sits clearly inside one of the ranges above, that's a sensible place to start. Someone swinging comfortably at 140 km/h isn't going to be well served starting the conversation at Extra Stiff, and someone at 165 km/h isn't likely to get on well with Regular.

Where it gets less clear-cut is right around the crossover, roughly 155 km/h, where either flex could be reasonable depending on the shaft. In that zone, how the club actually feels, where you're striking the face, launch and dispersion tell you more than a few km/h either side of the line. We wouldn't tell you to play the softest shaft you can get away with, and we wouldn't tell you Stiff is automatically the better option either. Both framings miss the point, which is finding what actually works for your swing.

Swing Speed vs Tempo and Transition

Swing speed is how fast the clubhead is moving, usually measured at or just before impact. Tempo and transition describe how you get there: the rhythm of the swing, and how smoothly or abruptly you shift from backswing to downswing.

Two golfers can post a similar swing speed and load the shaft quite differently getting there. That's worth knowing, but it's not a reason to build simple rules like a fast tempo needing a heavier shaft, or a smooth tempo needing a lighter one. Tempo is one input among several, not a formula, and it's genuinely hard to self-diagnose without seeing your swing on a monitor or with a fitter.

Does the Same Flex Need to Be in Every Club?

Driver and iron shafts don't have to match, and for most golfers they won't. If you're working out what to play in a driver, measure your driver swing speed specifically. If you're assessing irons, hit a mid iron on its own rather than assuming your driver number carries across.

There's no requirement that flex labels line up throughout the bag, and plenty of golfers run a different flex, or a different shaft type altogether, between their driver and their irons.

Steel vs Graphite

Steel isn't automatically for stronger or faster swingers, and graphite isn't automatically for seniors or slower swingers. Both are stereotypes that don't hold up once you look at what's actually available.

Graphite comes in Regular, Stiff and other flexes just like steel does, and plenty of golfers with real swing speed play graphite for the weight and vibration damping. Steel also comes in a wide range of profiles, from softer-feeling options through to genuinely stiff, low-torque designs. The choice between them is really about overall feel and fit, not a proxy for ability level.

When you're checking a used club, the condition issues to look for differ by material. On steel, check for significant rust, pitting, dents or bends. On graphite, check for splitting fibres, structural damage, or damage around the hosel. We don't treat shaft weight as a required check on our own listings, since it's not something we consistently measure or publish, but the condition points above are worth checking on any set.

What does SR flex mean?

You may occasionally come across SR on a shaft. It generally means Stiff Regular and sits between Regular and Stiff within that particular shaft range.

As with any flex label, we'd still check the exact shaft model rather than assuming every SR shaft feels the same.

How Can You Tell If a Shaft May Not Suit You?

A shaft that doesn't suit your swing can show up in a few ways: timing feels off, strike gets inconsistent, launch is higher or lower than expected, or dispersion opens up more than it should.

What it can't do on its own is tell you which direction is wrong. A slice doesn't automatically mean the shaft is too stiff, and a hook doesn't automatically mean it's too soft. Your swing path, angle of attack and how the clubface is delivered at impact all shape ball flight too, and any of those can produce the same miss regardless of what shaft is in the club. If something feels consistently off, that's a signal to get it looked at properly rather than to guess at a flex change.

How to Measure Swing Speed

The most reliable ways to check swing speed are a launch monitor, a simulator, or a golf shop or range with proper measurement equipment. Use your normal swing when you test, not your one big effort swing, since that's not what you'll actually be playing with.

If you're working out driver flex, measure driver speed with a driver. Don't average it together with your iron, wood or wedge speeds. Those clubs behave differently, and averaging them across the bag just muddies the number you're trying to get.

What to Check When Buying a Used Club

1. the exact shaft model
2. the stated flex
3. whether the shafts match throughout an iron set
4. whether the club appears to have been altered in length
5. the physical condition of the shaft
6. whether you already know a similar shaft has worked for you before

We don't include shaft weight as a required check here. It's a legitimate factor, but it's not something we consistently know or publish across our own inventory, so we're not going to pretend it's always available information.

This is also why we photograph and grade the actual club rather than relying on a generic condition label. See how we grade used clubs.

What If the Club Has an Aftermarket Shaft?

A club with an aftermarket shaft isn't automatically a better buy, and a stock shaft isn't automatically a worse one. An aftermarket reshaft can be a genuine upgrade if it was fitted properly for the original owner, or it can just be someone else's preference that has nothing to do with what suits you.

We wouldn't pay a premium for a fancy aftermarket shaft on the assumption that it must be better. A cheaper club with the right shaft for your swing is usually a better buy than an expensive aftermarket setup that doesn't suit you, no matter how good the shaft's reputation is in isolation.

Do You Need a Professional Fitting?

A fitting isn't only worthwhile if you're a single-digit handicapper. Golfers at pretty much any level can get something useful out of one. That said, a beginner picking up an inexpensive first used set doesn't necessarily need a full fitting before they start playing.

A fitting becomes more worthwhile once:

• you're spending significant money on a set
• you're genuinely stuck between two flexes
• your launch or feel seems consistently off
• your swing speed has changed noticeably
• you're considering an expensive reshaft

Outside those situations, using the guidance in this guide and buying sensibly used is a perfectly reasonable way to get most of the benefit without the cost.

SwingStock's Practical Way to Choose Shaft Flex

1. look at what you already play, and how it's working for you
2. check your clubhead speed if you can get access to a launch monitor
3. look at the exact shaft model, not just the letter stamped on it
4. don't choose Stiff for ego reasons
5. don't assume softer is automatically better either
6. weigh the whole club, head, shaft and condition, not the flex label in isolation

For most golfers shopping used, close and sensible beats theoretically perfect and expensive.

If you're building a full bag from scratch, our beginner's guide to used golf clubs covers where to start.

SwingStock Verdict

Shaft flex matters, but it's one part of a used-club purchase, not the whole decision. Start with a rough swing-speed range if you have one, treat Regular and Stiff as a starting conversation rather than a verdict, and pay attention to the exact shaft model and condition on anything you're actually considering.

Focused FAQs

What shaft flex should I use at 145 km/h?

Around 145 km/h sits inside the Regular range on our rough chart, so Regular is a sensible starting point. It's still worth checking how a specific shaft feels rather than treating the label alone as the answer.

What shaft flex should I use at 160 km/h?

160 km/h sits inside the Stiff range on our rough chart. It's also close enough to the crossover zone that feel, strike and dispersion are worth weighing alongside the number.

Is Stiff better than Regular?

No, neither is inherently better. The right flex is the one that matches your swing speed and how you load the shaft, not whichever sounds more impressive.

Can I use a Stiff driver and Regular irons?

Yes. Driver and iron shafts don't have to match. Measure or assess each separately rather than assuming one flex has to carry across the whole bag.

Are graphite shafts only for seniors?

No. Graphite comes in Regular, Stiff and other flexes, and plenty of golfers with real swing speed play graphite for the weight and vibration damping. It's a feel and fit choice, not an ability-level label.

Does a shaft that is too stiff cause a slice?

Not automatically. A slice can come from swing path, angle of attack or how the clubface is delivered at impact, regardless of shaft flex. A poorly suited shaft can affect timing, strike and dispersion, but it can't be diagnosed from ball flight alone.

What does SR flex mean?

SR generally means Stiff Regular, sitting between Regular and Stiff within that shaft range. As with any flex label, the exact shaft model matters more than the letters alone.

Should a beginner get fitted?

Not necessarily before their first set. A beginner buying an inexpensive first used set doesn't need a full fitting to get started. Fittings become more worthwhile once you're spending significant money, stuck between two flexes, or your swing speed has changed.