Boring USGA Groove Rule Facts

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usga-groove-wedgeNormally, at we like to post on interesting golf products, entertaining news, and hot spy chicks. But for now, were going to have to stray a bit for those who just crave nerdy golf information. Even though it seems super boring, too many people are talking about the "new groove rule" for us to ignore it any longer. So here's some information about the newest thing tour players have to complain about. Again, we cant imagine who would want to read about this stuff, but for those of you who do, here are some facts from the WedgeGuy(President, EIDOLON Golf).

The Truth about Grooves

By Terry Koehler
President, EIDOLON Golf, LLC and

The golf media generally is pretty thorough and accurate when it comes to such things as equipment and equipment rules. But in regards to the U.S. Golf Association’s impending new rule on grooves that is scheduled to go into effect next year, the media is off base. I have never seen such a level of misinformation before in this industry. And I’m betting you’re going to hear a lot more misinformation about the subject of grooves as 2010 approaches.

The media has messed this up so much that even PGA Tour players are talking about “when we go back to V grooves.” Does anyone not read what the USGA published on this???

In addition to reading in several places about “when square grooves are outlawed”, just this past week I received a “scare tactic” promotional email from one of the newer wedge brands, which announced right in the subject line, “USGA To Eliminate Square Grooves”. The email went on to say that:

“The USGA has implemented a rule change that the PGA Tour will adopt for next season, eliminating the use of square grooves on wedges.”

In this case, either this manufacturer didn’t really read what the USGA rule says, or they are just out-and-out lying in an attempt to try to sell you their wedges. I’m going to choose to believe that ignorance, not deception, was their fault here.

So, in the spirit of public (and accurate) information, let me set the record straight about what is going on with the “great groove issue”. With the hard facts, you can be the recognized expert in your group and at your club with regard to what the real story is about the new ruling governing grooves on wedges.

The Big Lie: "Square Grooves are Being Outlawed."

The USGA Rule does nothing of the sort. It does not propose to govern at all what the shape of grooves can be, or at least no differently than the current rule. Golf club manufacturers can continue to make clubs with grooves shaped like a “V”, a “U” or “square”. The USGA Rules have previously allowed, and will continue to allow, for a series of “straight grooves” with diverging sides and a symmetrical cross-section. The width and cross-section, according to the rules, “must be consistent” across the face of the club and along the length of the grooves. In other words, grooves can’t be slanted one way or the other to affect spin, nor can they be of inconsistent spacing.

The new rule, as it is currently written, calls for the grooves to be “straight and parallel.” The grooves must have a symmetrical cross-section “and have sides which do not converge.” The width, spacing and cross-section of the grooves “must be consistent” throughout the impact area.

On EIDOLON V-SOLE wedges, as with most others with CNC-milled grooves, the groove sides have a slight draft to them to allow the cutter to work more efficiently. Call it a “modified ‘V’” if you will. Most cast-in-place grooves have a “U” shape, as the sharp corners in the bottom of the grooves are filled in during the casting process.

The new rule does not require club manufacturers to rely only on ‘V’ grooves. Oh, and the rule doesn’t only apply to wedges, but to all clubs with 24 degrees of loft or more.

USGA Facts and Wording on the Manufacturing Process

But the new Rules do change the way club faces and grooves must be manufactured in order to comply, and the wording has three substantive parts.

  • First, it changes the way manufacturers have to measure our grooves and spacing. Up to now, we only had to concern ourselves with the groove width, depth and space between the grooves. Those requirements and measurements haven’t changed, but the USGA added a fourth measurement requirement that defines a formula for the volume of groove dimension per inch of face. In simple terms, square grooves would have to be further apart than ‘v’ grooves because they can channel away more grass and moisture.
  • Secondly, the rule adds a new aspect, in that we will have to ensure that the edges of the grooves have a slight radius on them (at least a .010” radius to be exact), whereas currently we can offer you the sharp edges that result from the milling process. This is the change that will likely be the key to a reduction in spin from the newly conforming wedges and irons made after the rule goes into effect . . . if it really does go into effect as they would have us believe.

This part of the rule will undoubtedly increase the cost of wedges, as it will take special cutters to impart this radius to the edge of grooves, and a cutter so configured will wear out quicker than those we currently use. Obviously, the foundries and their machine shops will have to build in these costs to the cost of heads they make for all manufacturers. Thanks a lot, USGA.

  • Third, and maybe the most important aspect of the new Rule governing grooves, however, is that it allows for a “condition of competition” which says that the implementation of the Rule is up to the tournament committee as to whether or not it is implied. Hmmmmm. And it further suggests that the rule “only be applied to competitions involving ‘expert’ players” – in other words, the PGA Tour and USGA competitions. The USGA has clearly stated that it intends to implement the Rule for its three major open championships in 2010, and all other USGA events in 2014. And the USGA has been very clear that all currently conforming clubs will be approved for play until “at least 2024”!

Here’s where it gets interesting again. As of this writing, the PGA Tour has not decided whether or not it will apply the rule in 2010 or not. In an interview before the US Open, a USGA official said that if the PGA Tour doesn’t apply the rule, then they probably won’t apply it to the U.S. Open, either. And the rumor on the street, as I understand it, says that some major manufacturers are “lobbying” the PGA Tour not to apply the rule in 2010.

And even if the Rule is applied, do you think for a moment that the ball manufacturers won’t produce balls that spin more if the pros ask for it? Remember the old Tour Edition that you couldn’t keep on a green? Maybe that soft cover technology will make a comeback.

This story is going to be well worth watching the next few months, and my bet is that it’s not nearly over yet. I wouldn’t even be surprised if the rule was overturned and rejected entirely.

If the rule does go in next year, EIDOLON and other manufacturers might have to slightly modify our groove shape, width and/or spacing to comply. But the biggest effect of this ruling is that we will all be required to add a radius to the edges of our grooves, so that they will not be as sharp. And if we want our 2010 wedges and irons to be on the USGA List of Conforming Equipment, any heads we make after Jan. 1, 2010 will have to incorporate the new limits.


Good God that was brutal. But there you go. All the information you will ever need to know about the new groove rule. For now, at least.


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