Grooves--what do they really do?

[TEPaul]

Barney Adams calls the grooves on golf clubs "garbage cans". Acording to Barney the grooves on a golf club don't actually put spin on the golf ball---Their function is merely to displace grass/water etc off the face since it's a clean face that puts spin on a golf ball. The larger the grooves (U or box grooves vs V grooves) the more junk is diplaced off the face and the greater spin imparted to the golf ball. Keep those grooves reamed out and clean if you want maximum spin and performance on your approach shots. Keep those garbage cans empty, in other words, before an approach shot if you're looking for maximum control!  

[Doug_Feeney]

Tom

I understand that on a full swing the grooves act as garbage cans at impact (displacing grass or the liquid that it becomes), and I have heard from the USGA B&I guys that there is minimal difference in spin with or w/o grooves, but ...

I believe they make a difference with wedges and other irons with less than full shots and around the greens - no compression (or at least less) of the ball against the face of the club.

[Yancey_Beamer]

Tom,
The Search For The Perfect Swing,by Cochran and Stobbs,1968 compares three different lofts of irons manufactured with and without grooves and tested dry and covered in soapy water.All results were the same regards grooves vs plain.
A fascinating book recently reprinted in paperback.Enjoy!
Yancey

[johnk]

The more friction that is created when the ball contacts the clubface, the more chance for spin. Wet grass does a good job of removing friction.

A perfectly smooth clubface with a perfectly hard, smooth ball would result in no spin.

Ever play ping pong?  You can use a smooth paddle, or you can have a paddle that has sand paper or rubber dots.  The rougher surfaces can create more spin.

Grooves can increase friction vs a smooth face, especially with a soft cover ball.  Clean, sharp, new grooves can create a lot of spin.

[Doug Siebert]

If you are playing with paddles covered with sandpaper or those rubber dots, you haven't played it at least 15 years.  The modern paddles have multiple layers of a smooth soft rubber like coating and put so much spin on the ball in the hands of a good player you can scarcely believe it!  Since the ping pong ball doesn't compress (at least on slower shots) the paddle surface does it instead.  The paddle is smooth because you want the maximum surface area contact, or at least that's what I assume is happening.

Bringing it back to golf, I believe the "garbage can" theory that has been around for a while is the only one that can explain the following facts we know to be true:

1) hitting from a clean lie produces more spin than a lie where grass gets in the way
2) using U grooves instead of V grooves produces more spin from a lie where grass gets in the way
3) the study Yancey Beamer mentions where having no grooves at all didn't matter whether the club was wet or dry (I would fully expect this was done from a nice clean lie)

I wonder about the soapy water part of the test, since the water may fly off the face during the swing.  Or at least gets squeezed off the face by the compression of the ball, which it can't do when the water is inside the blades of grass.  Should have tried the test with something that might stick to the face during an aggressive downswing a bit better, like lard or 10-40W

[BCrosby]

"In Search of the Perfect Golf Swing" by Cochran and Stobbs was published about 30 years ago. It's full of interesting engineering studies on golf. (A great book, btw.)

C&S did a study on grooves and concluded that under dry, clean conditions grooves didn't impart much more spin than a smooth face. If I recall their conclusions correctly, JakaB might be right. The primary function of grooves is to act like little trash disposal units.

Bob  

[John_McMillan]

Ever play ping pong?  You can use a smooth paddle, or you can have a paddle that has sand paper or rubber dots.  The rougher surfaces can create more spin.

I have played ping pong.  However, I have never played in grass long enough to come between the paddle and the ball at impact.  Until I do, I'm not sure how to translate the physics of a ping-pong paddle to the physics of a golf club.

[TEPaul]

I always thought that it was somehow the grooves themselves that imparted spin to a golf ball. Barney Adams, during a few hours of discussion a couple of years ago said in no uncertain terms that it's the clean club face that imparts the spin not specifically the grooves. All the grooves do or function as, according to Barney, is a way of displacing junk off the club face to in effect keep it clean so spin will be imparted by a clean club face---hence his description of grooves as nothing much more than "garbage cans". And his ultimate point was that U grooves compared to V grooves simply displace more junk off the fact of a golf club because they have a larger area for displacement.

[johnk]

OK, forget the ping-pong analogy.  The point is that: more friction = more possible spin.

Grooves increase the friction between the ball and the clubface.
A smooth club hitting a compressible ball will generate some friction.  A grooved club will generate more.  Whether that difference is significant under dry conditions depends on the player, clubspeed, ball, etc.

Barney Adams' view of grooves only being useful in grass situations is a simplification. Since a normal ball and clubface can generate enough friction to create spin under dry conditions, the difference between a smooth faced iron and one with grooves might not matter much.   However, grooves do increase the friction over a smooth face.

Drivers used to have more grooves than they do today.  People discovered that removing the grooves reduced the spin rate, which made the ball fly farther.  So in this case, the removal of grooves was a conscious decision to reduce spin even when wet grass was not involved.

[TEPaul]

"People discovered that removing the grooves reduced the spin rate, which made the ball fly farther.  So in this case, the removal of grooves was a conscious decision to reduce spin even when wet grass was not involved."

John:

My sense is that some people only think that's true. Whether it really is seems to be debatable, in my opinion. One could probably deduce that if drivers with no grooves really did make the ball fly father by reducing spin rate of the golf ball then no modern driver today would have grooves but of course most do.

The answer to a question like that could probably be accurately forecoming from the USGA tech center as they definitely have testing equipment that could determine something like that.

[Brian_Gracely]

One could probably deduce that if drivers with no grooves really did make the ball fly father by reducing spin rate of the golf ball then no modern driver today would have grooves but of course most do.

TEPaul,

Have you seen some of the modern drivers lately?
http://www.taylormadegolf.com/r7/

Not much in the way of grooves on there anymore.

[TEPaul]

Brian:

I have. Frankly, drivers without any grooves at all have been around for quite a while so who's to say they are nothing more than just another manufacturer gimmick that really has no effect on performance. Some who really know the equipment industry say that perhaps 95+% of what manufacturers come up with in new miracle ball and equipment offerings are nothing more than "no effect gimmicks". It's a little like the "placebo effect"---they work only to the extent some golfer thinks they work--only to find out a week after they buy it it really doesn't work!  

[TEPaul]

Dave:

It does seem to be common knowledge that hitting the ball high on the face of these new drivers creates maximum distance. I don't know if the ball is rolling up the face or doing the cha-cha on the fact but Frank Thomas maintains that the effect on distance of this new COR on clubs is simply that the ball stays on the face just a bit longer than in the past. That ever so slight additional time imparts a greater transfer of energy to the ball and more distance.

[Doug_Feeney]

Frank Thomas maintains that the effect on distance of this new COR on clubs is simply that the ball stays on the face just a bit longer than in the past. That ever so slight additional time imparts a greater transfer of energy to the ball and more distance.

TEP

That is exactly as I understand it, and this is achieved by making the faces thinner and therefore having the face "give" a little more and the ball compress a little less. The metal is more efficient at regaining it's shape.  The driver faces reach a point where they are too thin to have grooves.

[Doug Sobieski]

If I recall correctly, when Ralph Maltby wrote the essential text on club fitting and design many years ago, he made reference to the fact that one summer he decided to test some theories about grooves. He actually played all summer with a set of irons with no grooves, and his handicap actually went down!!

Doug

[Steve Lang]

 

has it been so long that folks forget what happened to balata balls when struck hard with a grooved club?

having chewed through a couple of Adam Clayman autograph Rawling Balata's at the Banff outing it's hard to imagine the groove edges don't do anything!

[Doug Siebert]

The other wild card in this is those crazy wedges that were sold on infomercials a few years ago with the replaceable face inserts.  They had a variety of inserts, and one was "illegal".  They showed (supposedly) average golfers using the illegal insert to back the ball up 60+ feet on a green, and a pro backing up a ball landing on a blacktop parking lot.

Now I'm as aware as anyone that most of the stuff pushed in those infomercials isn't worth your time to watch it for 5 minutes at 3AM, let alone the three easy payments + shipping and handling.  I'd sure love to talk to someone who had tried one of those, or better yet try one myself, just to see if the illegal insert really did spin the ball noticeably more from a clean lie than a normal wedge does.  If so, I'd wonder how those illegal grooves are different, and why they work better on clean contact -- unless maybe they have little spikes that dig into the ball so you get some major jizz on it but even a Pro V1 is shredded beyond repair after a couple shots.

[johnk]

I think Adams viewpoint is that for most players, if they played from dry fairways, grooves wouldn't be needed.  And that is true, but golf isn't played that way.  So his point is that the primary benefit of grooves comes in the wet rough.  I think that's true.

However, a grooved clubface can create more friction than a non-grooved clubface, and for certain clubs, balls and swing conditions, that will create extra spin.

Like everything in golf technology, you may ask: will that matter for the average hacker?  Probably not.  Are there players for whom it does make a difference.  Yes there are.

PS. On further thought about the drivers, I admit that another good reason that more drivers are groove-less these days is that the very-thin titanium faces can be weakened if they have grooves on them.

[KSS]

John Krystynak states an opinion as if it were fact - without any supporting evidence - example: his comment about grooves being able to create more friction than a smooth face.

What is the evidence for this proposition? - because there's lot's of evidence to the contrary.

Will he next ask us to believe that the grooved treads on automobile tires create better grip?

[Brent Hutto]

There is only so much friction that does any good. If the golf ball rotates rather than sliding up the face of the club then the amount of friction is sufficient for maximum spin and any additional friction is unnecessary. That is the basis of the claim in Search for the Perfect Swing. They found that during clean contact (dry face, no grass between club and ball) a normally smooth clubface with no grooves will make the ball rotate instead of slide.

Any foreign material between the club and the ball makes it possible under the right conditions for the ball to slide up the face somewhat. In those cases, grooves will allow the material to squish down away from the club-ball contact patch just like on a car tire displacing water. So for actually playing golf you definitely want grooved clubs (although on a driver it would only matter if you let the ball or clubface get wet or muddy).

As for the undeniable fact that sharp-edged grooves and soft-covered golf balls will result in shaving or scuffing, that is true but has nothing to do with the amount of spin imparted to the ball. The edges of the grooves can damage the ball but the point is that the ball could have been just as firmly planted on the clubface under perfect conditions if the grooves had been duller or not there at all. So the presence of scuff marks do not inform any discussion of whether grooves are required for maximum spin production.

Finally, I suspect the lack of grooves on some modern driver faces have to do with not wanting to weaken a clubface that's been thinned down to within a fraction of a millimeter of breaking.

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