What is Shaft Flex?
Shaft flex refers to how much the shaft bends during the golf swing. It's typically categorized as:
- L (Ladies): Most flexible
- A (Senior): Flexible
- R (Regular): Medium flex
- S (Stiff): Less flexible
- X (Extra Stiff): Least flexible
However, these labels aren't standardized across manufacturers. One company's "Stiff" might feel like another's "Regular."
How Flex Affects Ball Flight
Too Flexible (whippy):
- Higher launch angle
- More spin
- Shots tend to go left (for right-handed golfers)
- Inconsistent dispersion
Too Stiff (boardy):
- Lower launch angle
- Less spin
- Shots tend to go right
- Loss of distance
- Harsh feel at impact
Swing Speed Guidelines
These are starting points, not hard rules:
| Swing Speed | Suggested Flex |
|---|---|
| Under 75 mph | L or A |
| 75-85 mph | A or R |
| 85-95 mph | R or S |
| 95-105 mph | S or X |
| Over 105 mph | X |
Beyond the Label
Modern shaft fitting looks at more than just flex:
- Bend Profile: Where the shaft flexes most (tip, mid, or butt)
- Torque: Resistance to twisting
- Weight: Total shaft mass
- Frequency: Actual stiffness measurement in CPM
The Bottom Line
Don't get hung up on the letter. Get fit on a launch monitor where you can see the actual data. The "right" flex is the one that produces optimal launch, spin, and consistency for YOUR swing.
The biggest mistake I see is players choosing flex based on ego rather than data. There's nothing wrong with playing Regular flex if it produces better numbers. I've seen Tour players gaming R-flex shafts. Let the launch monitor be your guide.