Shaft Fitting Guide
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Ball
Speed 170 mph 160 mph 150 mph 140 mph 130 mph 120 mph 110 mph 100 mph |
Shaft
Flex X-Stiff Stiff/X Stiff Reg/Stiff Reg A/Reg A Ladies |
Vertical
Launch 11° - 12° 12° - 13.5° 12.5° - 14° 13° - 15° 14° - 16° 15° - 17° 15.5°- 17.5° 16° - 18.5° |
Ball
RPM 3000 - 3200 3200 - 3400 3400 - 3600 3600 - 3800 3800 - 4000 4000 - 4200 4200 - 4400 4400 - 4800 |
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To ascertain exactly what shafts are best suited to your swing it would be ideal to have your swing measured by a professional club fitter at a swing monitoring facility or pro shop. There are also numerous personal swing analyzers available to buy.
When a swing speed device is not available, the chart below may be used to approximate swing speed based on driver carry distance or the club used to approach the green from 150 yards. (Based on average club lengths and lofts.)
Swing Speed Conversion Chart
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Shaft
Flex Extra-Stiff Stiff Regular Flexible (A-Flex) Ladies |
Driver Swing Speed MPH
105 + 90-105 80-95 70-85 Less than 70 |
Driver Carry Distance Yards
260 + 240-260 210-240 180-210 Less than 180 |
Club From
150 Yards 8 or 9-iron 6 or 7-iron 5 or 6-iron 4-iron 3-iron/lofted wood |
EI Profiling
EI is a term used by shaft engineers regarding flexural rigidity and stiffness of a beam. The term is not typically used in marketing of golf clubs. In 2009 Bridgestone Sports filed a patent regarding EI.
EI=length of a segment 3 (cubed) X Load applied to shaft
48 Strain applied to load
E refers to Young's Modulus which is the ratio of stress to strain. I refers to 'inertia'.
Russ Ryden developed a machine that determines EI value with a 3 point bending test. Basically the shaft is placed horizontally on supports while a load is placed vertically at a central point. The shaft is marked in inches and precisely weighted. When the weight is dropped on the shaft, the deflection is noted and the process is repeated 36 times. They put the numbers into an Excel spreadsheet to determine the overall stiffness. His machines were developed to understand shaft bend profiles because he believes it is essential to the fitting process. They allow you to predict what to expect and are used to help individual needs during fitting.
High quality shafts will have similar EI profiles. It is all about consistency in the shaft.
R,S,X refer to shaft stiffness.
There is a diagram also shown on Mitsubishi website that he recommends where the
horizontal axis indicates tip to butt and the vertical axis indicates flexural rigidity-EI in kg of force (soft to stiff). The diagram shows that better quality shafts will have cleaner lines, but lower quality shafts will have wobbly lines.
EI=length of a segment 3 (cubed) X Load applied to shaft
48 Strain applied to load
E refers to Young's Modulus which is the ratio of stress to strain. I refers to 'inertia'.
Russ Ryden developed a machine that determines EI value with a 3 point bending test. Basically the shaft is placed horizontally on supports while a load is placed vertically at a central point. The shaft is marked in inches and precisely weighted. When the weight is dropped on the shaft, the deflection is noted and the process is repeated 36 times. They put the numbers into an Excel spreadsheet to determine the overall stiffness. His machines were developed to understand shaft bend profiles because he believes it is essential to the fitting process. They allow you to predict what to expect and are used to help individual needs during fitting.
High quality shafts will have similar EI profiles. It is all about consistency in the shaft.
R,S,X refer to shaft stiffness.
There is a diagram also shown on Mitsubishi website that he recommends where the
horizontal axis indicates tip to butt and the vertical axis indicates flexural rigidity-EI in kg of force (soft to stiff). The diagram shows that better quality shafts will have cleaner lines, but lower quality shafts will have wobbly lines.
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The EI profiling also helps to compare shafts which he believes will help predict if it will behave the same, i.e. give a player swing
consistency. Bottom line is that knowing the EI profile of a shaft will help with swing consistency and assists in the club fitting process. |
Russ Ryden's EI Profiling Machine
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