According to R&D: “In the Groove”


If you're a golf fan, you've likely heard plenty of discussion over the past several years about wedge grooves, USGA groove rules, and golf ball spin. But how do grooves really work, and what can you do to improve performance with your wedges?

To start with, let’s look at a simulation of a golf ball impacting a wedge groove.  The following image was generated using finite element analysis (FEA for short).  FEA is a computational tool used in the golf industry to predict outcomes of high speed golf impacts.

golf ball groove on Tour Trusty wedge closeup


The image above is a magnified look at the golf ball cover and wedge groove during impact.  Interestingly, the golf ball cover material only slightly conforms to the groove shape.  The top edges of the groove dominate contact while the remainder of the groove volume appears to be underutilized.

So why are grooves so deep if only the top edge is useful?

The answer is that the rest of the groove exists to make sure the top edges can do their job.  During a round of golf, you may find yourself hitting from a variety of places, including fairways, bunkers or rough. Additionally, extra moisture may be present from dew, sprinklers, rain etc.  All of those elements can and do come in between the club and ball during impact.  To combat this, golf engineers design a place for that material to go in the form of grooves.  At high speeds, grass, sand, water and other debris compress into the grooves, keeping the valuable groove edges free to impact the ball.  Without grooves, all of that foreign material covers the groove edges and robs you of spin and performance.  So even though you may end up with grooves filled with dirt and grass after a swing, you also probably ended up with a shot that flew nice and straight with a lot of spin.

How many grooves are actually used in a wedge shot?

A second FEA simulation below shows the imprint of the ball (red dot) on the wedge face during a full swing impact.

Impact on COBRA Tour Trusty wedge

 Only 5-6 grooves of the wedge actually contact the ball on a full shot.  That’s it!  If several of those grooves are dirty, spin generation can be reduced by 50% or more.  That can mean the difference between a wedge shot backing up or releasing forward, or a ball staying on the green or rolling off the back.  For this reason, better players will clean their wedges after every shot.  Next time you’re watching golf on tv, take notice of the caddy wiping down the club with a wet towel.  Pros spend too much time on their game to be undone by dirty wedge grooves!

Hopefully it is now clear how important grooves are to your wedge game.  So if you don’t already, try to keep your wedges and grooves clean during your round.  You’re sure to experience greater spin, better performance and more game enjoyment!

Article written by: Tim Beno, Sr. Research Engineer