Gear Effect, The Ball Flight Joker

A toe strike can cause a hooked shot for right handed golfers

With Derek MacDonald, PGA of Canada Class A Professional (Brockville CC)

Gear Effect is the joker of golf ball impact
Gear Effect is the joker of golf ball impact

It has been discussed by my friend, Andrew Rice, that the club path is King and the club face is Queen in relation to importance of ball flight and shot shape, not necessarily the swing.  I most definitely agree with Andrew, 100%, after seeing hundreds of thousands of shots on TrackMan.  However, I have recently added to Andrew’s ball flight explanation terms in keeping with the Royal Family theme and adding to it, the Ball Flight Joker, aka the Court Jester.

As I have discussed in previous articles, the club face is primarily responsible for starting the golf ball in a direction, and the club path is mostly responsible for creating the curvature of the golf ball.  As long as the club face is in between the target line and the club path, the ball will always be starting off the target line and moving towards the target line.  There is one situation where although this usually holds true, you may begin to see odd ball flights due to gear effect, aka, the Ball Flight Joker.

When the golf ball is struck off-center, towards the heel and toe of the club face, the club is going to rotate around the center of gravity (CG) of the club head.  If you strike the toe of the club face, this is going to cause the club face to open and rotate around the center of gravity in a clockwise fashion for right handed golfers.  When the toe is struck, the horizontal axis of the golf ball will then be tilted to the left or less to the right, for right handed golfers, depending on how much gearing has taken effect.  This is where the term “gear effect” comes from, just like two gears moving in opposite directions, the club face and golf ball react in the same manner (see Picture 1).  The opposite holds true for striking the golf ball on the heel of the club.  The club will now rotate in a counter clockwise direction and the horizontal axis of the ball would now be tilted to the right or less to the left, depending on how much gearing has taken effect.  Even 1 dimple left or right of the center of gravity of the club head will cause gear effect.  The further to the left or right you are from the CG, the more gear effect you will see take place.  These explanations represent horizontal gear effect.  Vertical gear effect will be discussed in a future article.

A toe strike can cause a hooked shot for right handed golfers
A toe strike can cause a hooked shot for right handed golfers

Here’s a tip to determine exactly where you are striking the ball on the club face.  Some of you may be immediately thinking of impact tape to see where you are hitting on the face.  Try not to use this tape, unless it is all you have, as the impact tape will drastically affect spin rate numbers because of lack of friction, which will also affect launch angles, launch directions, and won’t provide you with correct ball flights while the tape is on the face.  Instead of tape, use Dr. Scholl’s foot powder spray on the club face.  You will clearly be able to see the impact point without affecting spin rates, launch angles, and launch directions (see Picture 2 & 3).

So, what am I trying to get at?  Be careful when analyzing ball flight.  Don’t let the curvature of the golf ball tell you that you are coming too much outside-in or too much inside-out, test the impact point and figure out if that Joker is playing tricks on you again.