Weight vs. Flex

Let’s chat about driver shaft fitting today. This applies to irons as well, but we’ll focus on drivers in this discussion. 

Here’s a scenario. Say you have a player who is borderline between flexes and you want to try some different shafts. He has a little trouble hitting the shaft you gave him, so do you go heavier or stiffer? (The same applies to lighter or softer flex). 

Let’s start with one of my favorites – the “it’s all about the shaft” comment. Last time I checked, you aren’t hitting the golf ball with the shaft. If you are – you may want to consider other sports. Haha. That comment is like talking about cornering performance in a car and saying it’s all about the axel – after all, the axel connect the tires to the car, right?? The shaft does have a job – a VERY important job. That is to return the clubhead to the golf ball in a way that will maximize contact with the ball. Shafts will influence distance (by allowing the player to return the club head to get contact more on the center of the face), direction and head rotation (by getting a square face due to the correct amount of rotation). Typically, you will find bigger gains by changing clubheads than you will by changing shafts. Don’t believe me? The next time a player comes in with an older Callaway club with the new shaft tip on it, get measurements from the old head and the new head on his current shaft. Then try new shafts in his old head. Unless the current fit is really bad, the head change will yield more performance gains than the shaft change. Consider this – Jon Rahm has been playing the same shaft for the last 8 years. Not the same model – the same shaft.

Back to our scenario. We now know the responsibility of the shaft (return the head to the correct position at impact) and the head (transfer energy into the golf ball). Suppose we find the right head and we are very close to the right shaft. We’ve found the right family, but maybe we can tweak it to make it a little better? In tis case, the players swing speed is borderline between flexes, so do we go heavier or stiffer?

What does each do? Typically, heavier shafts will prevent a player from muscling the club. Muscling the club typically results in starting the downswing with the upper body. The heavier club will force to drop the club more from the inside and be less able to throw the club (over the swing plane). Remember the Momentus Swing trainer? He will also be less likely to flip his hands at it due the the increase in weight. His swing speed may slow slightly, but don’t be surprised if his ball speeds go up due to more centered contact. Conversely, stiffer shafts tend to have a little less torque (when you stay within the same family), a little lower ball flight, and will have a little less kick (due to increased stiffness). This will make it a little more stable at impact. 

Still with me? Here’s more specifics on our player… He has 103 MPH club head speed with the driver. His miss is left. He hits a pull hook with his current driver. His current driver is an older Callaway driver with a 65 gram stiff flex shaft that he wasn’t fit for. Ball speeds on that driver were in the 144-148 MPH range (1.44 smash factor, so pretty good). 

I put a similar loft Paradym head on a similar shaft from today to get a feel for where he would be with todays technology. Swing speed increased to 105, and ball speeds touched 150 MPH. He hit a few really good ones, but a few big, ugly hooks. Golf is a game of damage control – we need to fix the big ugly hook. Can a new club do that?? 

I noticed that on the hook, his path was left, and his club face was closed. My question is two fold:

• Is the path left because the shaft (club) is too light?
• Is the face closed because of the torque of the shaft being wrong (too high) for the player?

I moved him to a different shaft. In this case, I had him try a Ventus Blue shaft in a 60 gram stiff flex. The torque here was lower than his current shaft, but the weight and flex were similar. He still hit some great shots, but also hit a few hooks. Nowhere near as bad, though. Crossroads… Do you go heavier or stiffer? I still felt that he was coming over it due to the slight left path, and flipping his hands at it caused the closed face. I got a Ventus Blue 7S (70 gram shaft). The hook was gone. Path was great, face was good. A new problem surfaced – he hit a few soft fades, a block or two. his miss was now to the right. He tried to hook it and it was a slight draw. I didn’t like the two way miss, so we went to a different shaft – A Ventus Blue 6X (back to a 60 gram shaft, but in an extra stiff flex). This shaft has lower torque, so it doesn’t accentuate his hand action. His tempo was great, and the miss to the left was still gone, and he didn’t hit it right anymore either. He tried to hook it and couldn’t. Almost done.

What about settings? His flight came down, so I added a degree of loft. Spin, peak height, launch were perfect. Adding loft closed the face by 1/4*, which also guards against the loose fade.

In this case, I went stiffer. Typically, Heavier works more for an over the top move, active hands, etc., while stiffer works more for good tempo, but the odd loos shot. Oftentimes, you need both – heavier AND stiffer, and this is typically easier to spot. Consider this in your teaching as well. If you have a student who can’t keep the club on plane in the downswing, is his club too heavy or light? Does he hook it or slice it? Does he have a shaft that is too stiff or too soft. Don’t underestimate the value of an equipment tweak in a lesson- it may save you both a lot of time…

I hope this helps!! Happy Fitting.