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7 min read · Oct 1, 2023
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Golf shaft flex is an important factor to consider when selecting clubs. The flex of the shaft impacts many elements of your swing and ball flight. Matching your swing speed to the right shaft flex is crucial for optimizing distance and accuracy. Here is a detailed guide to using swing speed to choose the proper golf shaft flex.
Golf shaft flex refers to how much the shaft will bend during the swing. Shaft flex is measured by attaching a weight to the tip of the shaft and measuring how far the shaft bends. The most common types of flex are:
- Extra Stiff (XS)
- Stiff (S)
- Regular (R)
- Senior (A)
- Ladies (L)
Stiff shafts bend the least, while extra stiff shafts are designed for maximum stability. Regular flex is suited for average swing speeds by age, while senior and ladies flexes offer more bend for slower speeds. As a golfer’s swing speed increases, they will need a stiffer golf shaft to match their force and tempo. Using the wrong flex can lead to inconsistencies, loss of distance, and accuracy problems.
Swing speed is measured by using a radar-based launch monitor. The device calculates the velocity of the club head at impact in miles per hour (mph). The average male golfer has a driver swing speed of around 90–100 mph. LPGA Tour pros generate speeds of 105–115 mph, while PGA Tour pros reach 115–125 mph. Long drive competitors can reach 140+ mph.
Knowing your baseline swing speed is important for determining correct shaft flex. Swing speed can vary based on many factors like age, strength, technique, and body limitations. As golfers get older, swing speed tends to decrease. Strength training and swing mechanics work can help increase club head speed. It’s a good idea to get periodic swing speed measurements with a launch monitor to see any changes over time.
Golf shaft manufacturers provide general recommendations for matching swing speed to shaft flex. These are starting points based on data averages and player testing. You may need to adjust up or down based on personal swing characteristics and launch conditions. Here are the standard recommendations:
- Under 60 mph: Ladies Flex
- 60–80 mph: Senior Flex
- 80–95 mph: Regular Flex
- 95–110 mph: Stiff Flex
- 110+ mph: Extra Stiff Flex
- Under 60 mph: Ladies Flex
- 60–80 mph: Senior Flex
- 80–95 mph: Regular Flex
- 95+ mph: Stiff Flex
- Under 60 mph: Ladies Flex
- 60–80 mph: Senior Flex
- 80+ mph: Regular Flex
As you can see, driver swing speeds call for stiffer flexes than irons due to the length of the club. Wedges require minimal stiffness since they create less overall force. Matching flex to club type and swing speed is key.
While the above guidelines provide an starting point, every golfer has unique swing characteristics. Factors like angle of attack, club path, and swing tempo can impact shaft loading and launch conditions. Golfers should use data from professional club fitting and swing analysis to refine shaft flex choices.
Key launch monitor numbers that indicate shaft flex needs include:
- Ball Speed — Higher swing speeds require stiffer shafts to maximize ball speed. If ball speed is too low for swing speed, add flex.
- Launch Angle — Excessive spin and balloon trajectories usually indicate a softer shaft is needed. Low launch angles suggest going stiffer.
- Spin Rates — Too much spin requires added stiffness to reduce torque. Low spin suggests going softer to increase spin and launch.
- Dispersion — Consistent impacts indicate proper flex. High shot dispersion points to improper loading requiring flex adjustment.
Work with a qualified golf pro to use your data to dial in shaft flex, beyond just swing speed recommendations. Your individual attack angles, transition force, and tempo should dictate ideal flex profile.
As golfers get older, it’s common to lose some swing and club head speed. When this happens, you may need to transition to more flexible shafts, even if your old shafts were well fit. Pay attention to any swing speed changes:
- Loss of 5 mph or more — Consider changing to the next softer flex
- Loss of 10+ mph — Likely need to go down two flex levels
- Gain of 5+ mph — May need to increase stiffness
A stiffer-than-optimal shaft can reduce distance and accuracy as you get older. Using shafts that are too soft can lead to excess torque and instability for stronger swingers. Getting refit for shafts every few seasons can help you adjust your gear to match age-related changes.
Women and seniors need to pay careful attention to flex selection, even beyond swing speed:
- Women — Tend to have lower swing weights and transitional force, so they generally need softer flexes than men at the same speed.
- Seniors — Age-related strength and flexibility losses amplify the need for softer flexes in older golfers. Higher handicap seniors may play best with senior or even ladies flexed shafts.
- Slower SS — Swing smoothness and consistency can allow some slower swingers to use regular flex. Benchmark based on total performance, not just swing speed.
- Faster SS — Some strong and flexible seniors can still achieve fast swing speeds. This allows them to use stiffer flexes than age norms.
Work with a teaching pro to evaluate the total picture — speed, strength, technique, and age considerations for senior and women’s flex fitting.
Beyond basic swing speed selection, shafts can also help compensate for certain swing characteristics:
- Quick transition — Faster tempo pairs better with stiffer shafts to control torque and loading.
- Slower transition — Smooth and slower transitions match up nicely with more flexible shafts for proper loading.
- Steep angle of attack — Steep descents into the ball will require stiffer shafts for stability.
- Shallow AOA — Shallow attack angles increase vertical loading on the shaft, favoring softer flexes.
Work with your coach to determine if your swing traits require any unique shaft considerations beyond standard swing speed fitting.
While matching swing speed is the top priority, several other factors come into play during shaft flex fitting:
- Length — Longer shafts generally require stiffer flexes, as length increases leverage and torque on the shaft.
- Loft — Higher lofted clubs naturally allow more shaft bending, potentially changing perceived flex feel.
- Weight — Heavier club heads and swing weights tend to favor stiffer shafts to balance feel.
- Material — Graphite shafts offer more variability in flex design over steel options. Unique graphite weave patterns can fine tune stiffness.
- Kickpoint — Tip or mid-kickpoints change flex patterns. A mid-kick can feel softer in the mid-shaft than a tip-kick.
Test shaft flex across different lengths, head weights, and materials to determine the best profile across your entire club set.
Even with careful swing speed-based fitting, you may end up with the wrong shaft flex. Some signs you may need to go to a softer or stiffer flex:
Softer Flex Needed:
- Excessive directional dispersion
- Low ball speeds for swing speed
- High, ballooning trajecotries
- Vibrations/sting at impact
- Low launch angles
Stiffer Flex Needed
- Low or spinny drives
- Drop offs in distance
- Inconsistent face impacts
- Shots leaking left (RH golfer)
- Excessive club head lag
Don’t hesitate to get refit for shafts if your swing changes or your fittings show you are in the wrong flex zone for optimal performance.
One other advanced way to use shaft flex is to adjust your ball flight bias. Stiffer flexes can lower spin and launch while softer flexes add height and spin. You can manipulate shot shape through strategic flex adjustment:
- Lower launch/spin — Use stiffer flex to limit height and bring down spin rate.
- Higher flight — Softer flex increases launch and spin for a higher peak trajectory.
Just know that any flex change for trajectory bias should still keep you in the proper overall flex range for your speed. Work with an expert club fitter when attempting any ball flight tuning through adjustments to flex.
Selecting shaft flex based purely on swing speed will get you in the ballpark, but finding your own personal ideal flex profile depends on monitoring performance and optimizing launch conditions. Here are some final tips for dialing in your perfect flex:
- Get fit by an authorized club fitter with a launch monitor
- Try multiple head/shaft combinations to compare stiffness zones
- Use data like ball speed, launch, and spin to refine choices
- Factor in your swing tempo, transition, and attack angles
- Re-evaluate flex needs if swing speed changes over time
- Adjustments for aging, strength, and flexibility
- Confirm right flex across your whole club set
Matching your golf shaft stiffness to your swing speed and mechanics is one of the most vital elements of optimizing club performance. Take the time to understand how swing characteristics and club specs impact flex fitting. Knowing your personal shaft flex profile can bring your fittings and club selections into perfect alignment with your game.
