THE GREAT SQUARE GROOVE
Copyright July 1998 - all rights reserved
There have been some postings recently indicating that there are
some folks (including, sad to say, some club pros) that believe that
grooves are illegal. The truth is:
- They aren't.
- They never were.
There was a specific technical issue over Ping Eye 2 clubs made
1985 and 1989. The issue was never square grooves per se, but whether
grooves on this club were .005" too closely spaced. (Folks, that's
less than the thickness of a human hair.) Those clubs have been
so there are no major clubs that I know (neither pro-line manufacturers
nor the well-known component manufacturers) that have a problem with
legality of their grooves.
So why has there been so much storm and fury over square grooves?
story is an interesting one, so let me waste a little weekend time and
the history. First, a little background:
- The USGA is the "governing body" for golf in the USA. They have
the authority and responsibility to write and enforce the rules of
golf, including equipment rules.
- The PGA Tour is an association of touring professionals. That is,
the Payne Stewarts and John Dalys are the members of the PGA Tour. They
hire a "commissioner", to look after their joint interests (that is, to
run the tour). That commissioner, for the period in question, was Dean
Beman. Basically, the tour players "own" the tour, and set the rules
for admission to their private club, as well as exercising control over
the tour events.
- Ping, the club manufacturer, is synonymous with Karsten Solheim.
He is the engineer who brought us heel-and-toe weighted putters,
oversize aerodynamic wood heads (of real
wood, before metalwoods and graphite made them as popular as they are
today), and cavity-back irons. None of these innovations, as important
as they were, incurred a shred of scandal about legality. (BTW, the
company's name isn't Ping, it's Karsten. So they're literally
OK, all set now. Once upon a time......
1981: A change in the USGA rules allowed manufacturers
to put square grooves in the clubface. This was not intended to affect
but rather to enhance manufacturability; casting V-grooves had some
not shared by square grooves. At the time, cast stainless heads were
on, and the USGA wanted to encourage the more economical manufacturing
For some reason, only Karsten took advantage of the rule, making
square-groove Pings from 1981 to 1985 and grabbing considerable market
from the old-line major manufacturers.
1985: The Pings played well (they did what they were
to do). But their square grooves were shredding golf-ball covers.
the engineer knew what to do; he rounded the corners of the grooves by
.005" -- just enough to remove some "bite" on the balata.
Since he changed nothing about the rest of the clubface, that made the
surfaces between the grooves narrower by .01" -- that is, by .005"
along the groove at each edge of the flat.
Now the USGA rules (App II, 4-1e) specify that:
"The width of the grooves shall not exceed 0.035" (0.9mm)...
The distance between the edges of adjacent grooves must not be less
than three times the width of a groove, and not less than
Karsten believed that the width of a vertical-walled groove should
be the distance between the vertical walls. If that were the case, then
rounding the edges would never have changed either the groove width or
the distance between the grooves. For this reason, Karsten didn't even
bother to submit the "new" head to the USGA for approval. But
apparently there was some controversy on that point.
If you look in the rules today, you will see the 30-degree method
rounded grooves and an accompanying diagram that makes it very clear.
And, by that measurement technique, the rounded edges left the grooves
officially a tiny bit wider and the distance between them a tiny bit
smaller -- enough to be in violation of the rule. So why did I leave
them out of the quote above? I
left them out because -- Ta Da! -- they weren't there in 1985.
were added as a result of the Ping brouhaha.
Because there was no explicit rule for measuring "the distance between
the edges" of rounded grooves, there was an honest difference of
between Karsten and the USGA. Karsten measured between the vertical
of the groove. The USGA initially measured the flat surface, then came
with the "30-degree measurement rule" (see Appendix II of your
rule book for a picture of this). By Karsten's assumption, the Eye 2
legal; by the USGA's 30-degree measurements the Eye 2 was .005"
1986-1989: Someone sent the USGA a Ping Eye 2; it was
made public who sent it in. It wasn't Ping; Karsten felt this was a
change that didn't affect the measurement, so they didn't send one for
The USGA measured it, found it .005" out, and said so. The history
that I've read says that the USGA consulted with several manufacturers
V-groove clubs before making its decision, but I suspect that was
and not conspiratorial.
At that point, the PGA Tour announced its own rule forbidding
grooves in PGA events. I'm not sure it was the only time it
rules at odds with the USGA rules, but this was not a common occurrence
if indeed it had ever happened. This difference wasn't noticed
because Pings were the only square-groove club around, and Pings were
trouble with the USGA. So the PGA Tour looked like it was lining up
the USGA, when in reality it was hiding behind the USGA.
Note that the USGA had no bone to pick with square grooves; it
specifically to the spacing between the grooves of the post-1985 Ping
2. So the PGA was clearly working another agenda. What was it? Here are
a couple of possibilities:
- The PGA at this time released a study contending that square
grooves imparted to the ball a higher spin rate, especially from the
rough. This seems to be supported by other studies I've seen. However,
the PGA outlawed them because they "changed the character and nature of
the game", surely a gross overstatement.
- The PGA Tour is, in reality, the touring pros. Individually, each
of them is sponsored by equipment manufacturers. At the time, Ping was
selling game-improvement clubs to the public, and didn't have many
endorsers on the tour; the tour players' endorsements were almost
entirely for the traditiional, V-groove club manufacturers who were
losing market share to Ping.
So whether you believe that the PGA Tour was a bunch of old fogies
to ward off technological change (their position) or that they were
with their sponsors against Ping (Ping's position), they don't come
as especially noble. They tried to hide behind the unassailable
of the USGA (whose motives were never questioned; they had
to enforce the rule). But the PGA made the mistake of trying to enforce
a PGA rule that was totally different from the USGA rule, in intent and
-- as we shall see -- in effect.
1989-1990: Ping was in a tough spot; Karsten's very
life was in jeopardy. They sued the USGA and PGA for 100 and 200
respectively, as compensation for wrongly lost business.
It took only five months for Karsten and the USGA to reach an
settlement. The [very reasonable] components of the agreement:
- The USGA would clarify the measurement rules to properly describe
the measurement of grooves with rounded edges.
- Karsten would re-tool the Ping clubs to the rules as written.
- The pre-existing Pings already bought would be grandfathered.
This was important to Ping, as it gave confidence to future customers
that the company would go to bat for them.
The wording of the settlement included the USGA's agreement that the
dispute "was of a technical nature" and not a condemnation of
square grooves; moreover, "there was no competitive advantage to a
user of the clubs." At that point, the PGA Tour was hung out to dry.
Their argument was never the USGA's argument, and they could no longer
behind the USGA's skirt.
Just a brief side note: the wording of that last quote was probably
to say that there was no competitive advantage between the illegal
and the Pings with square grooves .005" further apart. No doubt this
is true. But if so, it didn't address whether square grooves per se
a competitive advantage, which was the PGA's contention. For some
the Tour never seemed to pick up on this and make an issue of it.
1990-1993: Still, the PGA didn't settle for another
years. They fought Ping's 200 million dollar suit, even while a court
blocked the tour's ban on square grooves and Karsten found a stable of
players to sponsor.
The fact that they settled just 6 days before the Karsten suit was
go to trial leads me to believe that the pros' sponsors were behind the
square groove ban. Over my fifty years, I've seen the tactic used over
over again by "the establishment" against an underdog: starve
them for business while paying lawyers to delay their getting to court
relief, and hope they die in the interim. If they survive to the trial
settle quickly (i.e.- concede defeat) and move on. It's just too
a pattern to be coincidence.
The settlement was worded in a way to save a little face for the PGA
Tour, but not if you read between the lines. It holds both Karsten and
PGA to respect the USGA's primacy in rulemaking. But Karsten agreed to
three years earlier anyway; this only changed the PGA's stance. Anyway,
(I hope you're sitting down) in exchange for Karsten agreeing to abide
the USGA rules, the PGA dropped its rule against square grooves.
So here are the somewhat more detailed answers to the question: "Are
square grooves legal?"
- They have been legal since 1981.
- A few square-groove clubs (Ping Eye 2 made between 1985 and 1989)
were illegal, but have been grandfathered and may be played legally
- Even those clubs were not illegal because of their square
grooves, but because of a technicality due to measurement after the
edges of the grooves were rounded.
- Square grooves were briefly banned from the PGA tour, due solely
to a PGA rule that had nothing to do with the legality of the clubs
- Depending on which study you believe, square grooves provide no
competitive advantage, or they provide slightly higher spin rates from
AM I BIASED?
... And, you might well ask, are my sources biased?
I probably do have a bias. As an engineer and an amateur clubmaker,
have a lot of respect for Karsten Solheim. As an engineer and a
I have a lot of contempt for legal eagles who try to solve commercial
technical problems through either litigation or, worse, legal bullying.
Thus I tend to be biased for Karsten and against the PGA Tour. But the
I have been on the technical committee of the regulatory body in
sport (sailboat racing in the Albacore class), and understand and
the USGA's position; I believe they behaved impeccably through the
thing, but I hardly believe that's at issue here.
- Golfsmith publishes Clubmaker magazine, where I got at least half
the facts in this article. Golfsmith undoubtedly sides with Ping; they
share a set of commercial interests. I hope I'm a sufficiently astute
reader to separate Clubmaker's facts from their opinion, but that's not
- Golf Digest, from which I got most of the rest of the story,
takes a lot of ads from equipment manufacturers, the vast majority of
them not Ping. Magazines are
notoriously beholden to their advertisers (who typically provide more
revenue than do sales of the magazine), so I suspect they'd be biased
toward the PGA and the traditional manufacturers.
So I was getting my information from sources on both sides of the
I hope I was able to maintain enough balance of my own to provide an
(if not completely unbiased) account.
>From: firstname.lastname@example.org (Dave Tutelman)
In article <mzimmersCqxqy0.email@example.com> firstname.lastname@example.org
>In article <CqxHKD.email@example.com>, >Dave Tutelman
>>1. The PGA at this time released a study
>>contending that square grooves
>> imparted to the ball a higher spin rate,
>>especially from the rough.
>Working from memory, an article in Golf Digest
>showed negligible difference in spin rates from a
>dry, tight lie, with the difference growing as the
>grass lengthened and/or became wetter.
>This may have been just a republication of the PGA
>article you mention.
As I responded in Email to Michael, I agreed with his surmise. But,
my amazement, I was able to find the issue in my basement. It was in
December 1986 issue.
The article involved original research by Golf Digest, with
and technical expertise borrowed from Karsten Manufacturing. The
was as Michael recollected.
- Square grooves give some negligible spin increase from a dry
- Square grooves give substantial spin increase from wet rough.
(Spin rates increased 25%-50%.)
It wasn't clear from the article whether the square grooves were the
sharp (pre-1985) or rounded grooves, but some of the text implies they
the sharp grooves. They admitted that they weren't sure whether the
were due to the shape of the groove or the "roughness" of the
knife-sharp edge. They also expressed skepticism about whether the
spin (they assumed their tests were accurate and there was
added spin) would be a help or a hindrance to either the pro's game or
- They quoted Tom Kite that he didn't WANT to suck the ball back
with any more spin that he could already give it.
- They pointed out that the high-handicapper almost always leaves
shots short of the the flag when they hit the green. Why would they
want more spin?
This is an update of an article posted to the Internet by the author in