Spin Rate and the Driver

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I was recently teaching an accomplished senior golf professional and he happened to hit three very interesting consecutive shots. They are illustrated in the image above starting from the orange circle and working up to the blue circle.

I thought there was some valuable information to learn from each of these three shots. Here is some TrackMan data to ponder:

Orange Strike

Spin Rate - 3252 Launch Angle - 7.5 Total Distance - 256.5 Club Speed - 103.6

Green Strike

Spin Rate - 2623 Launch Angle - 9.6 Total Distance - 269.5 Club Speed - 102.9

Blue Strike

Spin Rate - 1928 Launch Angle - 10.9 Total Distance - 274.6 Club Speed - 103.1

My experience has shown that golfers tend to be fairly consistent when it comes to club speed and this illustration shows us just that - there was a change of less than 1 mph between the golfers slowest and fastest swings. Nothing new there...

What is interesting is that where the ball was struck on the face, influenced the spin, launch and ultimately the distance that the shot traveled. You may have heard that with a driver you want to launch the ball high and spin it low. The purpose of this article is to get you to start believing it! 

Stay tuned as this is the stuff that can make a tangible difference in your game...

Launch Angle

The clubface is curved from top to bottom and this is called roll. If you have a 9.5 degree driver that means (assuming the manufacturer is correct) that your club has 9.5 degrees of loft in the center (picture the "equator") of the clubface. If you strike the ball lower on the face your club effectively has less loft and vice versa for a higher strike point. well hitting the ball higher on the clubface introduces more loft to the ball and it will thus launch higher - bingo! We've got the higher launch taken care of. As you can see the ball launched more than 3 degrees higher by elevating the strike point.

Spin Rate

But what about the spin rate? How do you get that down and what is ideal? I have great news, as this is a two for one deal. When you strike the ball higher on the face the "off-center" hit causes the clubhead to twist slightly during impact and this leads to vertical gear effect and a strike above the equator will have less spin than a strike below it. I prefer to see a spin rate somewhere between 1900 and 2400 rpm's if you're looking to really make the ball go. It's amazing what a strike point that's about 1/2" above the equator will do towards getting you into that optimal spin rate range.

If you're wondering where to strike the ball on the face the above photo is just about perfect - a touch above center for higher launch and less spin and a touch towards the toe for a hint of gear effect draw. Who wouldn't want to hit high launching, low spinning, baby draws that go 20 yards longer with the exact same club speed?

Collision!

Few golfers are aware of what really happens when a clubhead collides with a golf ball at high speed, not to mention how much an off-center collision can effect the flight of the ball. My hope is that this article and the accompanying video footage will give each of you a much better understanding of the importance of solid contact. I would encourage you to watch the following PGATour.com video a few times...

As you can see a strike away from the center of gravity of the clubhead will lead to twisting of the clubhead. While most of the twisting occurs after impact, a portion of it does occur during the impact interval. It is this twisting during impact that leads to gear effect which can greatly alter the flight of a shot.

An off-center collision will twist the clubface in any direction.

A hit high on the face will tilt the face upward and reduce the amount of spin on the ball, while a low strike point will deloft the face and increase spin rate. A strike towards the toe will open the clubface and increase draw or reduce fade and a strike towards the heel will close the face and increase fade or reduce draw. Interestingly, the clubface will tilt vertically (top/bottom) almost as much as it will horizontally (toe/heel).

There are seven shots in the video and if each of them had a neutral club face and club path during impact, the results of each shot due to gear effect would have been as follows:

Shot 1 - A strike above the "equator" of the clubface and slightly towards the toe. Ideal if you would like to hit high launching, low spinning, draws that go a long way.

A High Toe Strike

Shot 2 - A more pronounced high, toe side strike. This strike point is too far from aligning with the center of gravity of the clubhead to be beneficial. This flight due to gear effect would have been fairly high launching, low spinning and would not have faded as much as it might have appeared.

Shot 3 - Another extreme high, toe side strike along with a heavy descending blow - not good. High and right, but a fairly straight flight.

A Low Heel Side Strike

Shot 4 - A severely off-center hit where the collision is with a very low portion of the face and in the heel. Believe it or not this ball gets airborne and will almost always be an unimpressive high spinning,  low fade with very little distance.

Shot 5 - Charley Hoffman: I have seen numerous clips of high speed driver footage like this and I don't think I have ever seen one where I cannot detect any twisting at all. A slight downward attack angle. Appears to be very close to a perfect center of gravity strike - a truly rare event! Very straight.

Shot 6 - Matt Kuchar: A neutral attack angle along with a high, toe side strike. High launch, lower spin and a slight draw - boom!

Shot 7 - Luke Donald: About as solid as Charley Hoffman's shot, but the interesting thing about this clip is the attack angle - quite severely down. Solid and straight, but not optimal for maximum distance.

It is interesting to note that today's larger clubheads will resist twisting due to having a higher moment of inertia. MOI is a measure of a body’s resistance to angular acceleration or twisting. MOI really comes into play when the ball and the clubface meet someplace other than the sweet spot. The MOI of a club is higher for heel/toe mishits than it is for high/low mishits and therefore tends to be more forgiving on heel/toe mishits. However, golfers tend to mishit a shot further towards the heel/toe than they do high/low so the clubheads' resistance to twisting tends to even out.

Please know that physics is not selective and any golfer, pro or amateur, can hit any shot solidly or severely off-center. Also - no golfer can "stabilize" the clubface during or after impact due to an off-center strike.

This article shows you which part of the clubface is best.

I love this video footage and from here on out it will be required viewing for all my long term and golf school students. Would love to hear your thoughts....