Stiff – This range is still considered fast, but you most likely won't be out on Tour anytime soon. If you're between 97 and 104 mph with the driver, you need a stiff flex. ... If you're between 84 and 96 mph, regular is going to be best for you.
Finding clubs that are right for you can be a difficult if you’re not armed with the correct knowledge. The best avenue to take when buying new clubs is going to a club fitter, but even if you don’t get fitted, you still need to be conscientious of certain variables when getting new clubs.
One of the most important things you need to be aware of is what shaft flex is right for you. And although it’s not the only factor, looking at your swing speed can provide a general guideline to help you determine which shaft flex you should be playing.
You should consider that your swing speed for your irons might not extrapolate perfectly to driver (and vice versa), so while a certain flex might be right in some clubs, that might not be the case in others.
Our friends over at True Spec Golf shared some data with us that illustrates the shaft that’s right for you based on your swing speed throughout the bag. (True Spec and GOLF.com are affiliates of 8AM Golf).
TRUE SPEC GOLF